 ar-jedi
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Posted: 8/10/2007 10:31:51 PM
[Last Edit: 1/26/2008 7:32:21 PM by ar-jedi]
amateur radio bandplans www.arrl.org/FandES/field/regulations/bandplan.html www.arrl.org/FandES/field/regulations/bands.html www.arrl.org/FandES/field/regulations/Hambands_color.pdf VHF/UHF: www.icomamerica.com/en/support/kb/Article.aspx?Download=1919 <-- PDF HF: www.icomamerica.com/en/support/kb/Article.aspx?Download=1920 <-- PDF www.dxzone.com/catalog/Ham_Radio/Band_Plans/ |
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ar-jedi
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Posted: 8/11/2007 1:32:04 AM
[Last Edit: 5/4/2011 10:29:47 PM by ar-jedi]
NVIS –– Near Vertical Incident Skywave: a technique for short range HF communications hometown.aol.com/alonestaryank/NVISKIT.html www.tactical-link.com/field_deployed_nvis.htm www.qsl.net/wb5ude/nvis/ www.w0ipl.com/ECom/NVIS/nvis.htm Originally Posted By ThePrepared_com:
There is NVIS info spread through a couple threads so I thought I would try to bring the entire NVIS thing into this thread. I believe NVIS is a highly important part of survival communications. NVIS allows you to reach stations 0-300 miles away that would otherwise be missed in the skip using other methods. In my opinion you are better off being able to communicate with close communities who are able to respond quickly. What is NVIS (Near Vertical Incidence Skywave)? (From TacticalLink.com) NVIS , short for Near Vertical Incidence Skywave, utilizes high-angle skywave paths between stations instead of ground-wave or surface-wave in order to communicate via HF radio. NVIS was originally evaluated by U.S. Army Forces in Thailand during the Vietnam conflict in the mid-1960's It was found that Mobile stations, using whip antennas bent parallel to the ground, could communicate more reliably with their base-stations. Signal strengths would be weaker using high-angle skywave but communications would be more reliable, less subject to fading, and consistent between stations. This was because the intervening terrain was less of an absorber of signals. Terrain obstructions between stations, such as hills, mountainous areas, jungle growth, built-up areas with tall buildings, no longer become path obstructions with stations when NVIS techniques are employed.
NVIS Links NVIS Propagation Conditions hflink.com/propagation/ ARRL Power Point Presentation on NVIS (Great place to start looking for information) www.arrl.org/FandES/ead/materials/NVIS.ppt ARRL Doc File on NVIS Operation arrl-sc.org/Tech%20Presentations/Near%20Vertical%20Incidence%20Sky%20Wave.doc Hi-Q NVIS Antennas www.hiqantennas.com/ Field Deployment of NVIS (Actual setups and tests in the field) www.tactical-link.com/field_deployed_nvis.htm Elpa Antennas (No longer sold new but can be found from surplus resellers. Specifically made for NVIS) www.hflink.com/antenna/elpa/ Originally Posted By Gamma762:
www.athensarc.org/nvis.asp Originally Posted By pcsutton:
I have an IC-7000 with an HI-Q 5/80 vertical on my truck. The antenna has a 102" whip on top. I tie the top of the whip down to my trailer hitch so it doesn't hit stuff and behold.....it works GREAT as an NVIS antenna. If I want to DX...I just untie the bottom of the tether and allow the whip to stand straight up. Just talked to a guy in Jamaica from Ft Worth yesterday. Not bad for a mobile, given the solar cycle. NVIS from Army MARS: NVIS in Depth Quick & Easy NVIS Originally Posted By Gamma762:
http://www.signal.army.mil/ocos/ac/articles/fiedler/dfnjarng.pdf |
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ar-jedi
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Posted: 8/11/2007 2:02:53 AM
[Last Edit: 1/10/2009 1:33:54 PM by ar-jedi]
listening to public service and shortwave freqs using ham equipment Originally Posted By KS_Physicist:
Originally Posted By Nolan1964:
With a 2m mobile like yours jedi, could I listen to (118.000 MHz - 136.975 MHz) the aviation freqs? The first question's answer depends on the radio you're talking about. Most modern radios do have "extended receive" where you could hear aircraft through public service. Some older ones (and perhaps some new ones, I don't know) were restricted to receive on transmit frequency only. This specification (receive range) is prominently displayed, often right in the ads. let me clarify one thing here though. the ability to tune to a given frequency has to be matched by the ability to demodulate the signal you are looking for. in the example case, aviation band frequencies are AM, and not all HT's/mobiles have an AM mode. my Yaesu VX6R does, and thus i can tune in and listen on aviation frequencies using that radio. however this is not the case with the V8000 (my mobile) and the VX170 (one of my HT's). they are spec'd fpr RX from 137MHz to 174MHz, FM mode only. hence, there is no air band RX possible on either rig –– you can't tune there nor can you set AM mode. the Yaesu FT8800 (a popular dual band/dual receive mobile) will do AM across the full RX range, which will allow you to RX commercial aviation traffic as well as listen in on the "milair" frequencies in the 200-400MHz range. ––- Correct me if I'm wrong but I'm thinking this might be useful if SHTF. I know little about them except a buddy of mine had one in school and we never had a party interrupted by unwanted guests (police). I saw some Uniden 100ch and 200ch with very small price difference is 100 channels fine or go for more?
buying a scanner based solely on how many channels it has is roughly equivalent to buying a gun based on how many rounds the magazine holds. IMHO the total number of memories is one of the least important parameters. more important: - trunking capability. (*) - analog vs. digital decoding. (*) - frequency range. - scanning rate. - 12dB SINAD sensitivity. - adjacent channel selectivity. - auto-memory assignment. - PC interface. - power consumption while scanning. (*) before you buy ANY scanner, find out what type of radio system(s) your local municipality uses. ––> www.radioreference.com/modules.php?name=RR the radio system in your town could be an "old fashioned" analog narrowband FM system in the 150MHz range (VHF) or in the 460MHz range (UHF). these are the simplest to monitor; any garden variety scanner should work ok as will almost any 2m/70cm ham radio. but, your local police/ems/fire could be using the latest gear, which may mean P25/APCO-25 digital radios combined with channel trunking. in this case, you need a more expensive, more capable scanner which can interpret the digitial signals and track the trunking channel changes. there is no way to half-ass this –– you will get absolutely nothing without complete capabilities on the scanner. finally, if your local public safey folks have enabled encryption on their digital sets, you are probably SOL unless one of the local brainiacs has either cracked the key (highly unlikely) or it was leaked from the department radio technicians. ––- Originally Posted By aaron_fsp:
An HF ham transceiver usually has a general coverage receiver and can receive SW broadcasts, SW broadcasts/utilities, etc. www.primetimeshortwave.com/america.txt tf.nist.gov/timefreq/general/pdf/1383.pdf tf.nist.gov/timefreq/stations/wwv-wheel.htm ––- Originally Posted By aaron_fsp:
www.mediamax.com/aaron_fsp/Hosted/shack.txt ––- Originally Posted By NUCdt04:
I was looking at a radio like the Yaesu VR-5000 Linkey I like this radio because of the fact that it covers all the way up to almost 2600MHz. I also like the option to use it like a scanner for the surrounding areas. I work in my company intel cell and also help out with comm around here so I can grab a terp real quick if I pick up anything that sounds interesting. The one sold through HRO shows it's only cell blocked (as opposed to other models that require govt authorization- which I may be able to pull off, there is GSM cell coverage in the area). Are there other radios out there that have comperable (or better) coverage and are not cell blocked back in the dawn of mobile phones, the cell networks employed a technology called AMPS: the Analog Mobile Phone System. with a scanner capable of demodulating NB FM signals in the 800-900MHz band, one could listen in on phone conversations carried on AMPS networks. basically, you "snooped" the signal from the cell site to the handset using the scanner; in some cases this only gave you one side of the conversation, depending on how the nearby AMPS cell site was configured (the other side of the conversation was carried on a different frequency). our gov't got involved (what else is new), and made it illegal to offer for sale a receiver that could tune in the cellular band. hence the "hole" in the frequency tuning range of receivers such as the one you linked to above. not too long thereafter, use of digital cellular protocols became prevalent. you may have heard acronyms like CDMA, PCS, GSM, and so on. in these schemes, your voice is digitized (converted to 1's and 0's) in the handset, and sent as data to the cell site. the advantages of doing this are many-fold, including reduced power consumption of the handset (leading to longer battery life), better immunity to multipath and other transmission impairments (no more static), and the ability to subcode other data (like text messages). one other important advantage of a digital signal is that it makes snooping much more difficult –– approaching impossible for "casual eavesdroppers" without significant financial and technical resources. i'm telling you all this because unless you local mobile phone operator is using mid-1980's cellular equipment, you are not going to be listening to any cellular conversations. a CDMA, PCS, or GSM signal sounds like white noise on an FM receiver, and the frequency-hopping nature makes it impossible to follow anyway. summary: today, there is no benefit to having FM-only reception in the cellular bands. Originally Posted By NUCdt04:
We have pretty crappy power here... Ok won't lie the power here sucks. The generators are beat to death from the heat and constant running- plus a high load always on them. There are sometimes brown outs and small surges- I need a way to keep the radio protected from that. Also I'm guessing that I need a seperate power supply- do they have ones rated up to 240V? I have 120 in my room also but have an empty line on the 240 side- would rather use that if possible. like most amateur radios, the VR-5000 operates off of 12Vdc, in this case drawing a scant 0.7A (700mA). if you are concerned with the cleanliness of your power, you can power the radio all day (and then some) with a car battery placed outside your domicile with some wires running though the window. overnight you can attach an small, inexpensive battery charger (BatteryTender Jr, or similar) to replenish the electrons. or you can simply take the battery over to the motor pool (or similar) once a month, and put it on a bigger charger for a day. one benefit of using a battery is that it guarantees that the noise floor of the receiver is at a minimum. Originally Posted By NUCdt04:
Antennas..... I was thinking a horizontal long wire for the HF side because I can run some coax out my sandbagged up window to the roof and across to the roof of a post- what about VHF and up side of the radio? I'm guessing a vertical on the roof also- I can get away with it no problem but I'm trying to keep this in my budget- I can't start going crazy with beam antennas- plus there is no place to put them and I'd get some funny questions. for < 30MHZ, a horizontal wire antenna such as the G5RV is one suggestion. what say all you HF'ers? help this man out! for VHF, see if you can find a local plumber and about 10 feet of copper pipe. we can set you up with a J-pole of some configuration. on the other hand, your situation is RX-only, so almost any vertical element with a good match to your frequencies of interest will work. –– Originally Posted By Wolfcri:
I am not sure if the local police use digital radios or if that even matters... or what else this thing will receive. you have a very useful scanner, suitable for receiving analog FM signals. 1st –– you can get NOAA weather radio on one of 7 local frequencies. you will have to try each to see which is strongest. see the bottom of this link, the frequencies are in a horizontal table, all around 162.5MHz: http://www.nws.noaa.gov/nwr/ 2nd –– you *may* be able to receive the local police/sheriff/fire/ems/etc in either the VHF band (approximately around 155MHZ) or in the UHF band (around 460MHz). as noted above, your local public safety folks may have moved on to a digital system, in which case you are SOL. see http://www.radioreference.com/apps/db/ 3rd –– you can monitor amateur (ham) radio frequencies in the 144-148MHz, and the 440-450MHz range. you can find the frequencies of amateur radio repeaters in your area via http://www.ar15.com/forums/topic.html?b=10&f=22&t=604477#10323243 there are others but that should get you started. |
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ar-jedi
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Posted: 8/11/2007 2:25:25 AM
[Last Edit: 7/21/2008 6:43:41 PM by ar-jedi]
soldering, general and RF connectors
--- for your electrical projects, you will need two types of irons. the reason you need two is the same reason you need different types of guns -- different purposes = different tools. for "electronics" type soldering, meaning kit projects or repairs on relatively delicate equipment or with small dia wire (18 AWG or thinner), you should use a "pencil" type iron. typically the better ones have a base and then a pencil wand. interchangable tips allow you to pick a tip to suit the job. better bases have temperature controls built into them to hold the iron at a suitable temperature. below, in the upper right hand corner, you see my Weller pencil iron, with the thermostat on the base. as you can see, i am working on a somewhat delicate project, which is what this iron is designed for. with this type of iron, you can easily and safely work on both through-hole (TH) and surface mount technology (SMT) electronic components. the pencil iron's attributes are light weight, relatively low power, and carefully controlled tip temperature. losdos.dyndns.org:8080/public/ham/PocketTracker/DSCN1172_sm.jpg losdos.dyndns.org:8080/public/ham/PocketTracker/DSCN1150_sm.jpg the type of iron shown above, however, is not suited for soldering PL259/UHF connectors or similar larger jobs. the PL259/UHF connector requires soldering the coax braid to the connector housing, and the tip mass of the smaller irons is usually insufficient to generate enough heat to properly solder the braid. explanation: the long metallic coax braid and the connector housing conspire to "wick" the heat away from where you are trying to solder, leading to a cold solder joint. you may have experienced the same problem when using a std issue propane torch to solder (sweat) large diameter [1" and above] copper water pipes together -- the heat is transferred away so quickly that you can't get the joint hot enough to get good solder adhesion. note also that BNC, SMA, and N connectors use a different coax attachment scheme and can be reliably soldered with a low power iron. these three connectors do not require soldering the braid to the connector housing; instead, the braid is mechanically clamped by a threaded ferrule. ------------- so what to use for larger jobs, like the PL259/UHF connector, and for larger dia wires (14 AWG and heavier)? this problem can be solved with an iron with more mass at the tip and the ability to supply more heat to the tip. typically this means an old-fashioned pistol grip iron, 100W or so. however, for the past few years i have been using an EXCELLENT butane-powered iron and have found it to be extremely versitile. it will solder PL259/UHF connectors on, and also do relatively delicate work as well. moreover, the soldering tip can be removed and replaced with a hot air attachment for collapsing heat-shrink tubing. i heartily recommend the Weller Portasol, it has proven to be very useful for many projects. for pics of the Portasol. see losdos.dyndns.org:8080/public/weller-portasol/ -- see also this excellent series of tutorials... www.tangentsoft.net/elec/movies/ |
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ar-jedi
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Posted: 8/11/2007 2:45:47 AM
[Last Edit: 9/15/2008 9:32:21 PM by ar-jedi]
ham radio and the interweb -- perfect together
here is a start: APRS: a means for position discovery and distribution using RF and the internet... using a generic GPS attached to your radio, other amateur radio operators can track your movement using a web browser. in addition, data from automated weather stations and such are included as well. en.wikipedia.org/wiki/Automatic_Position_Reporting_System www.aprs.org/ www.openaprs.net/ <--- check it out, APRS data on Google Earth maps www.findu.com/ Packet Radio: TCP/IP over RF, with gateways between RF and the internet... this is infrastructure, not an application itself. it is possible to send SMTP email, for example, using packet radio. en.wikipedia.org/wiki/Packet_radio en.wikipedia.org/wiki/AMPRNet WinLink: send email from anywhere in the world etc using an HF radio... sort of self-explanatory, but note that it is in widespread use by mariners and and government agencies. en.wikipedia.org/wiki/Winlink www.winlink.org/ Echolink: VoIP (voice over IP) for amateur radio operators; interconnects via the internet and RF... using a PC, you can talk to other Echolink-connected hams, and also with Echolink-enabled repeaters. en.wikipedia.org/wiki/Echolink IRLP: internet radio linking project, connects repeaters using internet TCP/IP links... repeaters in distant geographic areas can be dynamically linked to create ad-hoc communities en.wikipedia.org/wiki/Internet_Radio_Linking_Project Hinternet: the implementation of wireless data networks over amateur radio frequencies using commercial off-the-shelf (COTS) hardware such as 802.11 access points and D-Star equipment. en.wikipedia.org/wiki/Hinternet DSTAR: a digital radio standard with features to interconnect with the internet en.wikipedia.org/wiki/D-Star ---
a PC, an internet connection, a microphone, and a speaker. PLUS A VALID CALLSIGN.  |
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ar-jedi
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Posted: 8/11/2007 2:46:42 AM
[Last Edit: 8/14/2007 7:12:59 PM by ar-jedi]
APRS - automated position reporting system
get an older 5W HT. the duty cycle on APRS is low, so the finals won't cook. if you are using a TinyTrak3 you can set it up to ping once every 2mins or 5mins or so. the APRS message is about 1 second in length, so this will not be a problem whatsoever with the HT -- even in a hot car. the other reason you don't want to run more power is that you'll be heard by many relay stations. while this may sound like a good thing, it's not. ps: btw to all... this is the canonical site for APRS info www.ew.usna.edu/~bruninga/aprs.html ar-jedi |
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ar-jedi
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Posted: 8/11/2007 2:55:11 AM
[Last Edit: 11/22/2007 10:37:52 PM by ar-jedi]
using amateur radios for transmitting on commercial or public safety frequencies a.k.a. legalities and related regulatory issues
the above is completely incorrect and is in fact unlawful. your amateur HT is not FCC type-accepted for use on public service frequencies. hence, you can not legally operate an amateur HT outside of amateur frequencies. a quick google will show you a recent case where a firefighter thought it would be "handy" to use an amateur HT on public service freguencies, namely his department's. the FCC was not amused and he and his chief were fined
i hope you are not involved in an incident where folks end up investigating why you were not using your issued duty radio and instead were relying on another piece of gear which was neither designed for the task nor type-certified by the FCC for use on public safety frequencies. ETA: www.qrz.com/download/main/mods.html
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no -- you are still in the wrong. the assumption underlying that question and the corresponding answer is that a modified amateur radio is the only available means of communication in a life or death emergency. that is, the FCC rule is intended to allow the person bleeding out/trapped/lost/freezing/whatever the ability to communicate with rescuers using any means possible. this is not the case if you, as a SAR responder, were issued a radio and you are part of a search and rescue operation. you are not the party in a life an death situtation. while an amateur HT may be used to communicate on amateur frequencies with the party in distress, communicating with your peers on public service frequencies must be with the radio you were issued. --- www.arrl.org/news/enforcement_logs/2002/1019.html
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no. amateur radio rules prohibit intentional encryption of transmissions. there are, however, legal methods of operation which enhance obfuscation. one example, use split mode operation. the TX and RX frequencies are different, and therefore a casual eavesdropper would have a tough time finding and then tracking the conversation. second example, use low TX power and high gain directional antennas. reception off to the sides and to the rear will be difficult. ---
true. very true. the problem with this approach is that it does not afford you any legal opportunity to learn, practice, and hone your skills. it's sort of like saying that the local PD/state police/FBI/ATF won't care who is CCW if SHTF so you should not bother getting a CCW permit, getting some training, learning your strengths and weaknesses, and practicing a million and one skills so when SHTF does happen you won't be carrying your Glock Mexican style ready to blow your nuts off. it's so easy and lazy to say "gov't agency XXXX won't care if YYYY happens, so i'll just worry about ZZZZ then." i, for one, would like to have my skillsets in place prior to SHTF, so i don't have to "learn on the job" while my family and i are in danger. you may choose to disagree. |
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ar-jedi
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Posted: 8/11/2007 3:04:33 AM
[Last Edit: 9/2/2008 11:06:10 PM by ar-jedi]
using commercial, FCC type-accepted radios for transmitting on amateur bands it is perfectly legal to use retuned commercial equipment on amateur radio frequencies. many hams retask surplus Motorola and GE public safety radios into amateur repeaters in the 6m, 2m, and 70cm bands. other folks use rugged Motorola and Vertex/Standard HT's for amateur uses as well. one benefit is that that these radios can continue to be used on public service frequencies -- good for first responders who also happen to be hams. one drawback is that most commerical radios are not front-panel programmable. in other words, a PC, some specialized SW, and an interface cable must be used to program memory locations before use. other commercial/industrial radios can be adopted for amateur use as well. here is one example -- an inexpensive Standard Horizon marine radio that is PC-programmable for amateur frequencies, and comes as a kit with lots of nice accessories that happen to be form/fit/function compatible with the Yaesu VX170. store.marine-radio-store.com/sthohxvhfham1.html
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(1) radio purchase info is one page back, e.g. www.marine-electronics-unlimited.com/Standard+Horizon+HX370.html and more generally www.google.com/products?q=HX370S&btnG=Search+Products (note: you *probably* don't need the more expensive Intrinsically Safe model [HX370SAS] as this model is specifically designed and individually tested to ensure that operation does not ignite nearby flammable vapors) (2) you'll also need to get a programming cable off of Ebay; any Yaesu VX6R/VX170 compatible cable should work. there are two types, one with the older RS232 serial port connector (DB9 type) and the other with a newer USB connector. i suggest that you get the latter type as the RS232 port is becoming less and less common on newer computers (especially on laptops). here is an EXAMPLE USB cable: cgi.ebay.com/USB-Programming-Cable-for-Yaesu-VX-6R-VX-7R-VX-170-VX6R_W0QQitemZ220259583364QQihZ012QQ note: i HAVE NOT used the above USB programming cable OR vendor; i link it merely as an example of what you should be looking for and the approximate cost. also note that some programming cables are generic in the sense that they don't have the *exact* connector needed for interfacing with the radio. this provides the vendor some flexibility since they are not making and stocking radio-specific cables. however, for you, the end user, a short adapter cable is needed to complete things. by way of an EXAMPLE, cgi.ebay.com/USB-Programming-Cable-for-Yaesu-VX-7R-VX-6R-VX-6E_W0QQitemZ360076336620QQihZ023QQ in the case above, the advertised cable does not directly interface to a VX6R etc -- one needs to get another cable, specifically Yaesu's CT-91. this info is noted in the auction text. the connector needed for the HX370S is a threaded, 4 conductor type, same as on the VX170, VX6R, and VX7R. you can see a closeup in this example auction: cgi.ebay.com/USB-program-cable-for-Yaesu-VX-6R-VX-6E-VX-7R-VX-7E-048_W0QQitemZ220264481835QQihZ012QQ  finally, the author of the popular FTBxxxx series of Yaesu programming software recommends, on this page, www.g4hfq.co.uk/links.html the following cable from Ebay vendor KAWAMALL: cgi.ebay.com/USB-Programming-cable-for-Yaesu-Vertex-VX-7R-VX-170-NEW_W0QQitemZ380051955508QQihZ025QQ again, i have no experience with this cable -- but the UK-based author of the Yaesu FTBxxxx series of programming SW definitely knows what he is doing. hope all that helps. |
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ar-jedi
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Posted: 8/11/2007 3:05:26 AM
[Last Edit: 7/21/2008 6:44:15 PM by ar-jedi]
building a sound card interface: radio <--> PC (e.g. for RTTY and PSK31 audio)
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excellent write-up above regarding interfacing the audio path. below, a simple DIY circuit for connecting many Icom and Yaesu radios with a PC's RS232 (serial) port for the purpose of using software (example 1, example 2) to program the radio. this circuit essentially duplicates the OPC478 cable offered (somewhat expensively, i might add) by Icom. this circuit is known to work with the Icom V8000, the Yaesu VX6R, and the Yaesu VX170. it should work with any Icom rig designed to use the OPC478 cable and most modern Yaesu mobiles/HTs(*). pics and schematic: losdos.dyndns.org:8080/public/ham/icom-opc478/ llosdos.dyndns.org:8080/public/ham/icom-opc478/IMG_1626_sm.jpg (*) some Yaesu rigs may require a 10K ohm pull-up resistor to 5V on the TX/RX lead. this biases the single wire net to Vcc, which these rigs evidently do not do internally. |
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ar-jedi
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Posted: 8/11/2007 3:09:43 AM
[Last Edit: 6/29/2008 1:20:14 PM by ar-jedi]
expectations of privacy with amateur radio communications
it depends. for one, the intercepting party must be in the coverage area of at least one of the communicating parties -- in other words, to hear *at least* half of the conversation the intercepting party must receive enough signal for subsequent demodulation. the communicating parties can, in effect, hamper this by (a) minimizing the amount of power they use, (b) employing directional antennas, and (c) employing frequencies which minimize distant propagation. for an example of the last item, there is no way for the intercepting party to hear a 50W 440MHz signal at a range of more than about 100 miles -- the curvature of the earth simply doesn't allow it, and 440MHz (and above) is only minimally subject to atmospheric effects such as tropospheric ducting. for two, the intercepting party must have a radio which can be tuned to the frequency of interest, and a antenna and radio setup, which when combined, have sufficient sensitivity at the frequency of interest to pull the signal out of the noise floor. note that i have skipped right over actually finding the frequency of interest. this can be quite easy (for example, if the intercepting party directly observes the communicating parties using FRS radios), or it can be exceedingly difficult and require the use of an expensive, lab-grade spectrum analyzer and associated antenna(s). for three, the intercepting party must have a radio which uses compatible modulation to the two parties in conversation. by way of example -- if the two parties are communicating using SSB mode, and the intercepting party has only a handheld FM mode rig, the intercepting party is not going to be able to hear the conversation. the same situation occurs if the communicating parties are using a digital mode, like P25, and the intercepting party does not have equipment capable of P25.
amateur radio rules, in an effort to maintain a civil environment that all can enjoy, prohibit the transmission of codes or employing means to obscure the content of the communications.
in the USA, the Federal Communications Commission (FCC) regulates the entirety of the electromagnetic spectrum, including the frequencies assigned to amateur radio. since many amateur radio signals can and do propagate outside the boundaries of our borders, the FCC works with international bodies such as the ITU to help harmonize the use of frequencies worldwide. for example, *eventually* the foreign shortwave stations present at nighttime (USA time) on the 40m band *should* disappear as they are moved elsewhere.
that is simply not possible due foremost to the reasons i enumerated in the first part of my reply, and second because the amount of monitoring required would simply swamp any central body. hence, amateur radio is "self-policing" in the sense that ham operators are expected to govern their own operations, and to (i'm looking for the right term here) provide "guidance" to operators who choose not to abide by FCC rules and good amateur radio operating practices. the worst case is that the offending operator is reported to the FCC, which will then result in the FCC issuing a NAV (Notice of Apparent Violation) to the operator. this may be a result of, for example, maliciously interfering with the everyday operation of a repeater, or perhaps operating on a frequency which your license class does not grant you privileges on. operators receiving a NAV are given a short period to craft a response to the FCC, but if the FCC finds the response wanting, they will issue a NAL (Notice of Apparent Liability) which basically says that the operator is guilty of unlawful amateur radio operation and depending on the severity of the violation advises (a) don't do that again, or (b) pay the noted fine, or (c) surrender your amateur radio license, or (d) all of the above. e.g. www.fcc.gov/eb/FieldNotices/2003/DOC-237767A1.html
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it depends. if i had, say, an unlimited US military size budget, i'd implement a spread spectrum, frequency hopping digital mode encrypted tactical squad/platoon radio system with a satellite uplink using a highly directional high gain dish antenna. from a land-based intercepting party's perspective, even a sensitive lab grade spectrum analyzer shows only a minor, non-descript increase in the ambient noise floor -- in other words, nothing seemingly interesting "pokes up". even if it were detectable, the intercepting party still needs (a) the correct digital demodulation type, (b) the correct decryption algorithm AND (c) the correct decryption key. none of these will be immediately obvious nor even recoverable by anyone but an extremely sophisticated, technically adept, and determined enemy. back to reality, using amateur radio gear for communications (e.g., during SHTF) is certainly less expensive. it does however mean that the level of sophistication, technical aptitude, and so on of a prospective intercepting party is significantly reduced. as an example, there is an entire aspect of amateur radio called "fox hunting" or "hidden transmitter hunting". a amateur radio club member plants a small, low power transmitter somewhere remote, and other members are challenged to discover it's location within a certain timespan. relatively inexpensive means are used to triangulate the location of the emissions. also, as you can see from the FCC example i cited above, this very same approach can be used for law enforcement activities as well. nevertheless, the very same radio procedures advised for military personnel in a combat zone can be used to defer detection of any type of radio communications -- frequent channel changes, keeping transmissions short, using OPSEC when communicating, need-to-know, etc etc etc. that said, if SHTF, i highly doubt that you will see bands of roaming Zombie "fox hunters" with sensitive receivers and small Yagi antennas looking for the source of your signal. note: if this does happen, i would suggest taping down the PTT key on one of your radios, placing it at the base of a tree, and then setting up a spotting scope and an AI AWSM in .338 Lapua about 500yds away. the buzzards will eat good. |
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ar-jedi
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Posted: 8/11/2007 3:18:26 AM
[Last Edit: 10/21/2008 3:11:20 PM by ar-jedi]
ham radio and SHTF: discussion
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tacked: www.ar15.com/forums/topic.html?b=10&f=22&t=612380
for HF, an Icom R75 receiver and an external antenna. for VHF/UHF, you might as well get a decent HT with an external AA pack. the FT60R comes to mind. then if you do need to xmit, you can, and it's portable. finally, by the time you are done you could have simply purchased an Icom 706MkIIG or a Yaesu FT857D/897D -- these are "shack in a box" rigs and will do everything you need to do. see www.ar15.com/forums/topic.html?b=10&f=22&t=614541 ---
here is a handy PDF denoting common HF frequencies used for emergency nets during times of national crisis, severe weather, and similar situations: www.ar15.com/forums/topic.html?b=10&f=22&t=612380 you will have to use an HF radio for regional/national/global news, and a VHF/UHF radio for local news. some radios these days, in fact the examples that i posted above, receive HF/VHF/UHF all in one box. you do need separate antennas for these bands.
there is no such thing new for under $200 unless you want a simple, inexpensive SW radio /or/ you want a VHF/UHF only radio for local communications. used, you may want to look at a HF rig such as the Icom IC735, Kenwood TS50, or Kenwood TS440/TS450. i would not bother getting a used HT as a new 2m HT is around $110, e.g. the Yaesu VX170.
10m-only is a waste of your time -- and at certain sunspot periods, like now, you won't hear much of anything. ---
all of the frequencies on the SHTF PDF frequency card are voice (SSB, AM, or FM).
all of the frequencies on the SHTF PDF frequency card are voice (SSB, AM, or FM).
all of the frequencies on the SHTF PDF frequency card are voice (SSB, AM, or FM).
there is no "one stop shopping" here. you will have to tune around the bands/frequencies listed on the SHTF PDF frequency card and gather intel. there is no "HF-based CNN" that you can simply dial into. if it were that easy, it would be just as easy for someone (even the government) to subvert it, right? summary: there is no one frequency which -- at all times of the day, all times of the sunspot cycle, and for varying distance from the SHTF epicenter -- will provide ALL of the information you are looking for. it ain't that easy. but it's not hard either. as a start, you may want to try the BBC or CBC SW broadcasts, since if our (USA) infrastructure is crippled our closest allies (England and Canada) may have useful information for you. you can also try listening to the time services out of Boulder/Ft Collins, as there are certain times per hour set up for dispersion of information of national importance. you can do the same with your local NOAA (VHF) station. and so on. finally, the control ops on the 14.300 marine maritime net are a great resource. if they don't know what is going on, no one knows what is going on. ALL THIS INFO, AND MORE, IS LISTED ON THE ABOVE LINKED SHTF PDF FREQUENCY CARD. if you have suggestions regarding other frequencies, or other modes, or anything else, please by all means make them known. my email address is on the card if you would rather do so in private. otherwise, print out that card, laminate it, and tape it to the top of your rig. ---
you need at worst two antennas. for HF: something like a long wire, OCF dipole, or G5RV. spending approximately $25 at Home Depot's electrical aisle would be a fantastic start. for VHF: a copper pipe Jpole or TV lead Jpole is about it; the former can be made for $20, the latter for $2. you could also splurge and get a dual band fiberglass antenna, like the $90 Diamond X50 -- and be good to go for the next 20 years. ---
you can do this with a $110 2m HT either simplex or via a repeater -- and also receive -) local NOAA "all-hazard" announcements including weather and amber alerts, -) local police and fire dispatch info if they are still on VHF high band, -) MURS radio transmissions, -) marine radio transmissions, -) and more. the 2m HT will operate on 6 x AA batteries. lithium primary batteries are good for 10 years. this is a good "closet radio" approach. keep a 12Vdc input power adapter as well, that way you can power the radio from your vehicle if/when you have to bug out. augment the 2m radio with a good shortwave radio and you are in business at low cost. |
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ar-jedi
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Posted: 8/11/2007 3:34:34 AM
[Last Edit: 8/14/2008 12:35:51 AM by ar-jedi]
QRP operation (low power/portable)
for on-person carry, you have basically two options: (1) amateur VHF/UHF HT (handy-talkie). this type of radio looks and operates similar to what you see the typical police officer, firefighter, or EMT carrying around. small, lightweight, short antenna, with either an integral or a detachable battery pack, an HT can be hung from your belt, clipped to your molle/etc, or stowed in your backpack. HT's are used to talk in one of three ways: HT to HT (called simplex operation), HT to fixed station/base (also called simplex), or HT to repeater. while the first two scenarios are quite range-limited due to the low power output of the HT (typ 5W) and the small antenna (typ ~4" to 15"), the repeater situation is altogether a different one. utilizing a repeater, an HT can be used to communicate over an area of hundreds of square miles. i explain repeater operation in detail about 3 or 4 posts down in the Ham Radio 101 thread which is permanently tacked to the top of this forum. just to close up on VHF/UHF, depending on where you live there may be from 0 to 10 repeaters reachable using an HT. if you are way out in the sticks, it will likely be 0. if you are near a relatively populated area, it will be more like 5. examples of VHF/UHF HT's are the Yaesu VX170 (2 meter only=VHF) and the dual band Yaesu VX6R (2m and 70cm=VHF/UHF). this class of radios generally cost around US$130->US$250, depending on features. (2) low power amateur HF radio (also called a QRP radio). QRP is a "Q-signal" meaning "reduce your power". in the amateur community, the term "QRP radio" generally describes an HF rig which outputs around 5W, although some models produce up to 10W. a QRP radio also has features which minimize power consumption while receiving. for example, there will be settings to turn off all of the display and key backlights, and so on. and, a QRP rig will work on lower DC input voltages than typical HF radios, which in turn facilitates operation from different types of battery packs. why use a QRP radio? well, for remote operation (either on foot or at a campsite), the amount of available battery power will limit operating time and transmit power. hence, a QRP radio maximizes your overall operating time. with a QRP HF radio, you can talk either about 5000 feet, or about 5000 miles -- depending on band conditions, the quality of your antenna, soil resistivity, quality of your receiver, and your ear. QRP is a real "art form" in amateur radio; you generally have to know what you are doing to make DX (distance) contacts, and this requires practice, dexterity in antenna hanging, familiarity with the quirks of the ionosphere, complete knowledge of advanced features of your radio, and a keen ear for tuning. now the tough part. the primary issue with operating HF while portable is the antenna. HF requires long antennas for efficient transmitting and receiving; a short antenna hurts on both counts. hence, the antenna is the critical factor for remote operation. you can play this two ways: (a) operate while walking with a vertical antenna sticking up out of your pack, or (b) operate while at camp using an antenna you assemble from your pack. option (a) is employed by many folks; you can see some nice pics here (click on the Meet the Moderators jpegs at the bottom): www.hfpack.com/ note that Europeans, especially those in the UK, are especially active in man-portable QRP operation. they dig it. option (b) is employed by many folks as well. you simply bring along a radio, a battery, and a portable antenna, and set it all up on a picnic bench at camp. the antenna can be a roll-up type (google "yo-yo-tenna") or a pre-fab dipole type which assembles like a tent pole (google "buddipole"). typical all-mode radios for QRP operation include the Icom 703+, and the Yaesu FT817ND. the former is popular with the picnic table crowd, and the latter is extremely popular with the manpack crowd. note that these are multi-purpose, all-band, all-mode radios that also double as shortwave (SW) receivers. there are also available some very simple, very power-efficent HF QRP radios that operate CW (morse code) on a single band. these types define the true essence of QRP operation: simple, low power, task-specific radio. any way you do QRP, you'll need an external antenna of some type, a microphone (for voice) or a key (for CW), and ideally as much battery capacity as you can carry. more QRP info/links here: en.wikipedia.org/wiki/QRP_operation also see home.frognet.net/~mcfadden/wd8rif/seorat.htm www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=11136 Icom 703+ in an example pack: (link)  final note: almost every high power (100W) HF rig can be dialed back to output only 5W, or thereabouts. hence, you can "run QRP" with a radio such as the Icom 718. however, current consumption on receive with a non-QRP rig will be much higher than a true, designed-for-QRP radio. this will impact battery life significantly. an example comparison: Icom 706MkIIG HF radio --> ~ 1.5A on receive. Icom 703+ QRP HF radio --> ~ 0.3A on receive. --
ah yes, the perennial ham radio question.
this is called a "QRP" (=low power, typ 5W) radio. like the Icom 703+, it has a defined purpose in mind: man- or field-portable radio.
correct. the 5W is where the trouble starts...
on VHF/UHF, the range is going to be the same as a generic 5W output dual band HT (FT60R/VX6R), assuming you use similar antennas. HF is a different story altogether. on a really good day, 5 watts and a decent antenna will get you 5000 miles. on a bad day it will get you about 5000 feet. on all of the days in the middle, it will be hit or miss. with 5w output, you will likely be able to hear many more stations than you can talk back to. these days, the noise floor of good amateur receivers is below the noise level of the atmosphere. with a good aerial, you'll definitely hear DX stations all over the world. with 5W, it will be tough to get back to them. even 80m, which is a regional band, will present difficulties talking into the next state. so now you are asking, "ar-jedi, you have not painted a very positive picture here. clearly Yaesu had some purpose in mind for the FT817, and hell -- from what i've read -- worldwide Yeasu has sold something on the order of a hundred thousand of these radios, plus over on Eham people seem to love them. so, what's the deal?" the deal is that HF QRP radios fit a defined purpose -- low power portable operation, and you need to understand the limitations of such. you need a good HF antenna -- an efficient antenna is a must. morever, QRP begs for using CW (morse code), and more recently the digital mode PSK31. these are modes uniquely suited to low power operation. all this good stuff (antenna + CW) may add up to squat if the ionosphere is just a little uncooperative though. there are no guarantees with HF operation, ever, no matter how much power you run. with just 5w, there is that much less leeway. the upside is that QRP radios sip electrical power at a rate that embarrasses most all QRO (typ. 100W or higher) rigs. and, QRP radios operate down to far lower voltages than typical QRO rigs. hence they are far lighter as a system, since you don't have to carry such a big battery pack.
this is not optional -- you will HAVE to. google Buddipole, Buddistick, YoYoTenna, and so on. the choice of VHF/UHF antenna is arbitrary. you can use a rubber ducky or something with more gain.
no. i've looked into this extensively for my Icom 703+. the answer is no. stop looking, it is a waste of money to try to do it. folks are going to point you to the Tokyo Hi-Power FT817 companion amp, and you'll stop in your tracks when you see the price tag. put the idea of an external amp out of your mind. you can buy a used FT857 for a tiny bit more than what a used HL-100BDX will cost you. and the import situation is awkward as well.
yes, and no. sucky answer, i know. most experienced hams will steer new hams away from HF QRP radios. their rationale is that there is little margin for error with QRP. if your antenna is poor, if your SWR is high, if your feedline is lossy, and so on, you will have difficulty. if the sunspots are not out, you are going nowhere with 5w. put a 5w bulb in a nightlight, and turn it and only it on at night. you can hardly see the other end of the room. a 100w bulb changes things dramatically, doesn't it? the other argument is that the FT817 makes a poor HT; you can buy a FT60R/VX6R, which is a "proper" HT, and it gets the NOAA weather stations as well (~162.5MHz, where [astonishingly] the Yeasu FT817 will not receive). another point is that more and more HT's are truly waterproof, which makes them more field-portable than the FT817. that said... if you are the patient, thinking type, and you realize that you are not going to QSO with Germany every day on 20m with 5w, and maybe not even once a month -- and you desire a lightweight, power efficient radio and you have the funds and/or the time to buy/build various portable antennas, then a QRP radio might be for you. if you plan on doing a lot more listening than transmitting, a QRP radio might be for you as well. you can get the BBC or listen to statewide rag chews on 80m very easily on the FT817, and it sips power while you are doing it.
get a mobile radio, like the FT857, and a power supply (such as the Samlex 1223). instant fixed station.
yes, you do... keep reading.
talking to folks in "other states" implies needing HF, unless you have a very widespread linked VHF/UHF repeater system nearby. so you need HF. that means you need a big antenna (figure $20-100 for one, depending on what you do) and a tuner (unless it's built into the radio, figure on spending $70-175 for a good one, for example from LDG). ---
see www.ar15.com/forums/topic.html?b=10&f=22&t=593963 the Icom 703+ QRP radio that i use has an integral autotuner. it is actually quite capable, and will match beyond the 3:1 that is advertised on the spec sheet. however, it does have it's limitations -- it will not match an end fed random wire (~3000 ohm feedpoint), for example. so you need a "reasonably resonant" antenna to drive. i've been using two antennas -- first is the commercial Yo-Yo-Tenna Deluxe (link). this a a dipole type which you extend as needed to the band of interest. next, i use a homebuilt UnUn to drive a end-fed sloper antenna. you'll need to buy/build such a device and then you'll need 2 pcs of 28AWG wire about 50 feet long. i throw one wire over a tree branch (i cleverly have an old 1/2" copper elbow soldered on the end for weight) and then you extend the other wire (the counterpoise) along the ground underneath the former wire. here is the design i copied: (link). also see (link).
here is the problem: with a 100W output (QRO) radio everything gets bigger: the tuner, the battery, etc. -- all of this contributes to a bigger and heavier box. non-QRP radios are not really designed for (1) really low current consumption on receive, nor (2) operation from voltages lower than about 11.7Vdc (that's 13.8Vdc - 15%). hence, you don't get nearly as much mileage out of your battery capacity with a non-QRP rig. of course, the limitation is that you get fewer watts out the RF connector... if you decide to go with a 100W radio might i suggest looking at the Yaesu FT450AT? it's relatively small, has an integral autotuner, has IF DSP, and right now it's priced very attractively ((link). this radio has gotten it's fair share of good reviews over on Eham (link). since you have dual band VHF/UHF on the FT8000 already, you just need an HF rig. the internal autotuner on the FT450 will save you a lot of space, and save you the space needed to link the rig with the tuner via coax. in the end i decided that the difference between 10W and 100W was not worth the added weight and reduced operating time. in fact, in my view one would mostly be *listening* during SHTF/TEOTWAWKI, not transmitting. at ~300mA, QRP radios sip power on receive. yes, you'll need to get the wire up up higher and such to get the same reach on transmit as a 100W radio. but i don't plan to need to bust pileups during SHTF. |
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ar-jedi
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Posted: 8/14/2007 12:20:45 AM
[Last Edit: 1/26/2008 12:01:03 PM by ar-jedi]
HF antennas, a work in progress a dipole antenna, graphic courtesy of Scottman:  a fan dipole, graphic courtesy of Scottman:  ---
+1M on the G5RV. here is the one to get: ebay link reviews and more info: www.eham.net/reviews/detail/2202 i have this antenna strung up between two trees, only about 20' high, and it works great. it is extraordinarily constructed, top quality heavy duty parts everywhere right down to the silver/teflon PL259 connector. --
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ar-jedi
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Posted: 8/14/2007 12:22:11 AM
[Last Edit: 1/10/2009 1:32:04 PM by ar-jedi]
The UPS guy delivered your first HF radio –– Now what? PHASE 1: (0) Erect an antenna of some sort. It could be a commercial product or a simple wire dipole. Longer, better. Higher, better. (1) Forget about transmitting –– for at least 7 days. Learn to receive first! This isn't VHF/UHF FM –– most SSB signals are not just going to jump out at you. At times, QSO's may be going on nearly on top of each other, and how you tune and use your radio's various features will determine how well you can hear. Moreover, there is no "squelch" function in SSB-land; you can't just set the radio to scan for active frequencies. (2) Tune for beacons located in the USA; for frequencies see mega list of beacons. (3) Tune for WWV (USA) / CHU (Canda) time stations: 2.5MHz, 5Mhz, 10MHz, 15MHz, 20Mhz / 3.330MHz, 7.335Mhz, 14.670MHz. (All are AM mode. You will hear a once-per-second click, and then a voice announcing what the time in UTC will be "at the tone"). (4) Tune for active QSO's in the phone and CW areas of 80m, 40m, and 20m bands. These *should* be fairly easy to find. Don't forget to switch modes (CW, LSB, USB) as you tune around the bands. Learn to recognize the "Donald Duck" quack sound of being a little off of a strong SSB signal, and which way to tune based on the sound. (5) Copy down some call signs from the QSO's you've heard, and look up those calls in the upper left hand corner here. Then click the "Details" link, which will give you a page similar to this. (6) Note the locations of the beacons and stations you are hearing. This information gives you a good idea which way your optimum paths are and what the propagation situation is currently like. Compare this data with beacons and stations heard at different times of the day. (7) Look up the "DX windows" for the 160m, 80m, and 40m bands. Listen for "CQ DX" calls from US amateurs. See if you can hear both ends of the ensuing QSO's. (BTW, if you are a US station, do not answer CQ DX calls from a US station! –– Instant LID status will result). (8) Read your manual and understand the benefits and side-effects of the receive mode features of your radio –– for example, DSP noise reduction and so forth. Employ these features to help resolve weak stations and/or cut down on hiss and band noise (QRM). a few things you will note: –– the top (phone area) of 40m is shared with foreign AM broadcast stations. you will hear these at night, a lot. –– google for an online list of shortwave (SW) radio stations, like the BBC World News or Radio Free Europe. their prime transmitting times don't always coincide with your chosen listening times, but you'll find some interesting stuff in the SW bands. –– from a DX standpoint, 10m through 15m is pretty poor right now due to where we are in the sunspot cycle. these bands will pick up over the next few years. PHASE 2: Listen... tune... and listen more. And listen to some well known/well run HF nets: www.14300.net/ www.smeter.net/stations/hf-amateur-radio-nets.php www.smeter.net/stations/hf-stations.php www.ecars7255.com/ More time stations: www.smeter.net/stations/hf-time-frequency.php –– Originally Posted By R-32:
Originally Posted By Jamess67:
I have the 857d,,,, Now I just have to figure out how to use it. switch over to 40M band, start spinning the funny looking knob... keep in mind that the 40m band is currently shared with international shortwave stations; at nighttime (in the USA) you will get tons of interference on 40m. if you want to listen to Croatian music or Radio Netherlands, simply wait until it's dark, switch your rig to AM, and tune around the 40m band. my advice for breaking a new HF radio/user is to try 20m/40m during the day –– but at night 80m is likely a more usable band unless you can find a quiet hole on 40m to sit in. at least that's the way it is here on the east coast. –– en.wikipedia.org/wiki/20_meters The 20 meter amateur radio band is a portion of the shortwave radio spectrum, comprising frequencies stretching from 14.000 MHz to 14.350 MHz.[1] The 20 meter band was first made available to amateurs in the United States by the Third National Radio Conference[2] on October 10th, 1924.
The 20 meter band is widely considered among the best for DXing, and is one of the most popular (and crowded) during contests.[3] Several factors contribute to this, including the band's large size, the relatively small size of antennas tuned to it (especially as compared to antennas for 40 or 80 meters) and its good potential for daytime DX operation even in unfavorable propagation conditions. en.wikipedia.org/wiki/40_meters The 40 meters or 7 MHz band is a core amateur radio frequency band, spanning 7000 to 7300 kilohertz, allocated to radio amateurs in all countries worldwide. The 40 meter band was made available to amateurs in the United States by the Third National Radio Conference on October 10th, 1924. 40 meters is considered the most reliable all-season DX band, most useful for inter-continental communication at night. It is extremely useful for short to medium distance contacts from local contacts out to a range of 500–1500 km, depending on conditions, during the day. In higher latitudes, daytime inter-continental communication is also possible in winter, for example a good path often opens between Japan and northern Europe in the hours leading up to European midday from late November until late January, with a long path opening to the west coast of the United States and Canada after midday.
For many years the portion of the band from 7100-7300 kilohertz has been allocated to short wave broadcasters outside the Americas and not available to radio amateurs outside ITU Region 2. At the World Radio Conference WRC-03 in 2003 it was agreed that the broadcast stations would move out of the section 7100-7200 kiloherz on 29 March 2009 and that portion would become a worldwide exclusive amateur allocation afterwards. Discussions on releasing the remaining 100 kHz of the band to amateurs at a later date will continue in future conferences. Several European countries have now allowed amateur communication in the 7100-7200 kilohertz section on a shared non-interference basis as an interim measure. Due to the 24 hour nature of the band, the wide variety of ranges that can be spanned with it, and its shared nature, it tends to be extremely crowded, and interference from other amateurs and broadcasters can be a serious limiting factor. In addition, amateurs in east and south-east Asia have suffered severe interference from illegal users in recent years. en.wikipedia.org/wiki/80_meters The 80 meter or 3.5 MHz band is a core amateur radio frequency band, allocated frequencies from 3.5 to 4.0 MHz in IARU Region 2, and generally 3.5 to 3.8 or 3.9 MHz in Regions 1 and 3 respectively. The portion of the band used for voice communications is sometimes referred to as "75 meters". The 80 meter band was made available to amateurs in the United States by the Third National Radio Conference on October 10th, 1924. 80 meters is the most popular band for regional communications networks through the late afternoon and night time hours. It is usually reliable for short to medium distance contacts, with average distances ranging from local contacts within 200 miles/300 km out to a distance of 1,000 miles/1,600 km or more, depending on atmospheric and ionospheric conditions.
–– Originally Posted By jagchaser:
I stopped in a radio store yesterday and bought a icom ic-706mkIIG and a 80/40/20/15/10 meter parallel dipole antenna. Anybody on now that I could try to listen in on? tons of people! you just have to find them... here is a reference card that will be handy: http://www.ar15.com/forums/topic.html?b=10&f=22&t=612380 remember though, that you need to have AT LEAST two things – that is not a problem whatsoever. let's play a bit... first some easy stuff... note that in no case should you transmit below! you can simply disconnect the microphone for now. your 706 receives VHF FM. so, connect your big HF antenna (temporarily!) to the VHF RF connector. tune around 162.55MHz FM. hear NOAA announcing the weather on several nearby frequencies? very good. you'll note that the exact frequencies for the NOAA stations are documented on the card above. there are seven frequencies –– one will be strongest in your area. with the big antenna still connected to the VHF connector, tune around 121MHz but switch the mode to AM. rolling around there, you *should* be able to pick up some aircraft transmissions, although this may be a no-go if you are far from a metro area or well off the air routes. keeping the antenna on the VHF connector, tune around 144-148MHz FM –– this is the 2m ham band. a little bit of research in the Ham 101 thread (page 1, about halfway down) will point you towards an online reference for finding local repeaters. you should be able to hear conversations on the repeaters, or perhaps just the repeater key up every 10 minutes and ID itself (may be in voice or morse code). now switch the antenna back over to the HF input. tune to 10MHz AM. you may be able to hear the tick-tick-ticking of the WWV time station coming from Ft Collins Colorado. after the 50th second of every minute, an automated voice will announce, "at the tone, the time will be XX:YY". now tune to 5MHz AM , and then to 20MHz AM. all of these signals come from the same place, but how well you can hear them is a function of the ionosphere and your antenna system. again, these frequencies are illustrated on the card linked above. since it's dark now, your best bet for hearing ham QSO's (clever name for conversations) is to tune around the 75/80m band –– 3.500 to 4.000MHz. near the bottom of the band you will have to switch to CW mode, and you'll hear folks sending morse code. north of 3.600MHz, switch to LSB and slowly tune for voice amateur radio traffic. tuning in HF-land requires a bit of acquired ear –– don't get frustrated at first. during the day, 40m band traffic will pick up as well –– and without the interference caused by the shared use of the top of the 40m band by international SW broadcasters. 40m is CW at the bottom (below 7125), LSB at the top. on any day after about noon eastern, there is almost no way you will not be able to hear traffic on 14.300MHz USB (20m ham band). the marine maritime net has been running there for 30+ years. net control stations will announce themselves and solicit check-ins. you may not be able to hear both sides of these conversations –– this is always an issue with long distance radio communications. finally, a note about your radio controls. the RF gain dial and preamp button need the most consideration. initially, leave the preamp off and put the RF gain control at about the 12 o'clock position. when you tune in a station, try to back the RF gain down until the background noise is minimized but you can still hear everyone. using the preamp is sometimes a necessary evil for pulling in weak stations, but it does have the side effect of raising the noise floor somewhat as well. soon afterward you'll learn that a modest amount of DSP NR (set it to 2, 3, or 4 initally) will make tuning and listening more pleasant by cutting out a lot of background noise. –– Originally Posted By jagchaser:
Maybe this is what has lost me. There are 2 ports for the antenna and they just say ant 1 and ant2. I dont see anywhere to hook it up to VHF. look on the side of the 706mkII chassis adjacent to the connectors. click here: http://losdos.dyndns.org:8080/public/ham/icom-706mkIIg/pics/DSCN3863.JPG the top one says "ANT 1 HF/50" <–– that is for HF and 6meters the bottom one says "ANT 2 144/430" <–– that is for VHF (2m) and UHF (70cm). –– Originally Posted By jagchaser:
I can get a few stations with morse code in the 3600-4000 LSB but I am not hearing any conversations yet. I wonder if I need a tuner for this thing? a tuner is not required to receive. Originally Posted By jagchaser:
There I found something at 3.720 I cant really make out what they are talking about but there are 2 guys discussing something. if the audio sounds distorted it is because you are off frequency a bit. tune up or down a bit and see if it improves either way. tomorrow try out 20m and 40m, the latter you should get some activity on and there won't be the interfering noise from europe. listening to WWV on several frequencies (2.5, 5, 10, 20) will aid in determining propagation in that direction. also see the canadian time station equivalents (note that one of the CHU frequencies has changed effective 01 JAN 2009, and the SHTF card does not reflect that yet). |
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ar-jedi
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Posted: 8/14/2007 12:22:51 AM
[Last Edit: 1/22/2008 9:42:35 AM by ar-jedi]
using an external autotuner
i don't have an 857 or Z100, but... generally when you press the Tune button on a modern rig OR do the same via an external tuner which is umbilical'd to a modern rig, the radio switches to CW mode, injects a 2KHz carrier to the audio path, and turns on the transmitter at about 5W. the directional coupler at the RF TX egress point measures the reflected power, and then the radio (if equipped w/ an internal tuner) or external tuner (like yours) starts a binary search of L and C values to find the correct match for the load. a few seconds later, the tuner will have found a match and transmitting will be halted. the radio mode will be auto-returned to its previous setting (e.g. USB), so no further manual action should need to be taken by you. at this point you are ready to go on with transmitting. note that most tuners (internal and external) have features to remember prior search results. that is, they store the transmit frequency and the discovered L/C combination in a lookup table. later, if you re-initiate a tune near that frequency, the radio uses the remembered L/C values as a starting point. this effectively reduces the time to tune.
the radio, upon getting a "tune now" signal from the tuner, should temporarily switch to CW as noted above. when tuning is complete, the tuner will negate the "tune now" signal and the radio will swap back to your original settings. btw, you can't tune up in SSB without some audio input -- keep reading...
completely normal. in SSB mode the radio transmits essentially no RF power when there is no audio input. you'll note that if you whistle or speak when TX'ing, the power meter will (should) indicate higher RF output. this is the basis of SSB (suppressed carrier) modulation: no audio input, no RF output. contrast with FM, where there is ALWAYS 100% RF output regardless of audio input. ps: initially, you will have to play with your microphone gain and speech compressor settings a little bit to get your audio (as received at the other end) "peaked". this is dependent on your voice characteristics, how loud you speak into the mic, how far it is from your mouth, etc -- your best bet is to find a local ham, and talk to him on SSB to give you some feedback on your voice quality. beware if you crank up the mic gain and/or speech compressor settings too much, it will sound like crap. first, use the default settings from your manual, and work from there in gradual steps. --- |
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ar-jedi
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Posted: 1/22/2008 9:35:37 AM
[Last Edit: 7/20/2008 12:16:16 PM by ar-jedi]
HF baluns explained
for what frequency? you can make a balun for HF quite easily. you can't make a balun for UHF easily. there is a great ARRL text on this subject, "Understanding, Building and Using Baluns and Ununs" www.arrl.org/catalog/images/8982.jpg you can order it from the ARRL website, about 90% of the way down the page here. ps: to everyone wondering what a balun is: en.wikipedia.org/wiki/Balun
BALUN is a concatenation of "BALANCED-UNBALANCED" and generally refers to a device which takes a balanced signal and converts it to an unbalanced signal, or vice versa. now then, what's that mean? in a balanced transmission line, there are two conductors which carry equal but opposite signals. (you could also say that the second signal is phase-shifted 180deg from the first). there is no "ground" per se in this mode. 300ohm TV lead, and 450ohm ladder line are examples of cables that carry balanced signals. (aside to EE's: balanced can be looked at as differential signaling). in an unbalanced transmission line, there is one conductor which carries the signal and the other conductor is a reference, generally "ground". (aside to EE's: unbalanced can be looked at as single ended signaling). one method or the other is not a better way to carry RF, in other words both unbalanced and balanced transmission lines can work equally well. so why do we care? for two reasons: 1) the output of a amateur radio transceiver is typically unbalanced. however, a great many antenna designs (for example, a true dipole) really want to be driven by a balanced source. enter the BALUN, which uses a transformer or a matching section of some sort to convert the signal from one type to the other. 2) the use of ladder line is cumbersome due to the fact that nearby any metal changes the characteristic impedance. for example, if you tie wrap ladder line to a tall tower, you may discover the impedance of that section has wandered way off from what you'd expect. coaxial cable does not suffer from this problem, as the signal-carrying conductor is completely and equally surrounded by the braid and/or foil shield which is the reference. so we are kinda stuck here -- it's more practical to carry RF signals on coaxial cable, but lots of antenna types want a balanced signal as input. and that's why BALUNs exist, to meld the two together.
not quite. the ideal reference antenna is a dipole. let's use 2M FM as an example -- there is a 1/4wavelength radiator up, and a 1/4wavelength radiator down. the overall height therefore is 1/2wavelength, or about 1 meter. the "counterpoise" is the element on the bottom. is is a necessary, essential part of the dipole and can not be ignored nor done away with. it does not reflect anything either; it is a radiating/receiving element, just as the top part of the dipole is. however, it is possible to substitute a real metallic ground plane, or perhaps a "virtual ground plane" using short downward sloping elements. this is typically referred to as a 1/4wavelength ground plane antenna. the lower half of the ideal dipole is mimicked by the ground plane. (incidentally from above it should now be apparent to you that a dipole antenna really wants a balanced signal fed to it, that is one with one signal 180degrees out of phase from the other. if a dipole is fed with coax cable, RF currents can be found on the shield of the cable and this will distort the raditation pattern.) n.b. some antennas have non-driven elements parallel to the radiating element; the elements behind the driven element are called reflectors. a three element yagi, for example, consists of a driven element (it's really just a regular dipole antenna), a reflector behind it, and a director in front of it. compared to the dipole on the middle, the reflector is marginally longer, and the director is marginally shorter. |
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ar-jedi
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Posted: 1/22/2008 9:35:49 AM
[Last Edit: 10/7/2008 9:38:06 PM by ar-jedi]
programming cables and SW for VHF/UHF radios
i have a VX6R and an FT8800. regarding programming... you only need one cable, and an adapter (which you can make yourself if handy, see the following thread): archive.ar15.com/forums/topic.html?b=10&f=22&t=610833 you need two pieces of software: www.kc8unj.com/vx6.html <-- donation-ware www.g4hfq.co.uk/ftb8800.htm <-- US$18.50 the latter can import from the former. so, manually enter all of your frequencies into VX6R Commander; program your VX6R; import the data file into FTB8800; program your FT8800 -- effectively, the two radios are now cloned, and all of your channel numbers/names/etc will be the same. --
as noted above, get FTB8800.
yes.
the electrical layer protocol for the VX6R and FT8800 are exactly the same. all you need to do to use a VX6R cable with the FT8800 is make a short (passive) "converter" cable to adopt the 1/8" plug to a DIN connector. the easiest way to go is to find an old PS2-style mouse or keyboard, and snip the DIN connector off, leaving about a 6" tail on it. at radio shack or equivalent, obtain a 1/8" stereo (3 conductor) jack (not plug). the jack can then be soldered onto the end of the stub you just cut off, and you are in business. insert the VX6R programming plug into the jack, and insert the DIN connector into the back of the radio. if you want to go this way let me know and i will provide the correct connections (a whopping 2) for the adapter cable. i made a similar adapter myself to use with my FT8800. you don't need 90% of what you see in the pics below -- just a 6" end piece of old keyboard/mouse cable, a 1/8" jack, and a hot soldering iron. losdos.dyndns.org:8080/public/ham/yaesu-ft8800r/pics/DSCN3170_sm.jpg losdos.dyndns.org:8080/public/ham/yaesu-ft8800r/pics/DSCN3172_sm.jpg --
i rec'd an IM requesting "how"... on the DIN connector (and therefore the back of the FT8800), PIN 2 is ground. PIN 3 is data. here is the view AS SEEN ON THE RADIO JACK (the female side = sockets):  here is the view AS SEEN ON THE CABLE END (the male side = pins):  also see www.burtonsys.com/PS2_keyboard_and_mouse_mini-DIN-6_connector_pinouts.html and losdos.dyndns.org:8080/public/ham/yaesu-ft8800r/pics/DSCN3172_sm.jpg to program your VX6R, you have either a CT91 "Y" adapter, or some kind of special cable that has a 4 conductor plug on the end. i'll assume first you have a CT91...   on the VX6R's "stereo" 3.5mm connector, there are three connections: tip, ring, and ground. the tip, well, is self-explanatory. the ring is set just behind the tip and insulated from it. the ground is the rest of the metallic part of the connector, and is sometimes called the sleeve. the ground (sleeve) is ground. the ring is data  hence, configure your NEW FT8800 adapter cable to connect DIN PIN 2 to ground (sleeve), and DIN PIN 3 to ring. this allows use of the VX5/6/7's CT91 "Y" adapter with the FT8800. if your cable has that special (stupid?) 4 conductor screw-in plug on it, the same connection scheme is used. in this case, there are two rings, one closer to the tip and another behind it. the one closer to the tip is the data. the ground (sleeve) is the same.   n.b. there is a ton of info on the cables/pinouts/etc at www.kc8unj.com/ click on " Interface Cables " in the left panel. --
the problem sounds suspiciously like you don't have the ground wire connected up correctly. the usual symptom for this is that the reads are corrupt. check your cable's ground wiring. did you buzz out your DIN connector? or said another way, how did you determine what wire goes where in the DIN connector that you cut off the mouse or keyboard? --
--
i take paypal.  the above just-get-the-right-connector approach works for ANY Yaesu radio (base, mobile, or HT) and also works for ANY CI-V equipped Icom radio (base, mobile, or HT). i use the same level converter assembly (shown above) with the following radios:
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ar-jedi
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Posted: 1/22/2008 9:35:59 AM
[Last Edit: 10/19/2008 11:13:08 AM by ar-jedi]
example HF station, KISS-style (KISS = keep it simple, stupid!) new HF/ham folks, shown below is an EXAMPLE of a HF/VHF/UHF "all mode" fixed station. this minimalist station consists of a radio, an automatic antenna tuner, and a power supply. not shown are the two (2) antennas (one for HF, another for VHF/UHF) which are located outside the house at the end of the two coax cables shown disconnected. the radio (box in the middle with the most dials and big display) is an Icom IC706MkIIg, which is a so-called "shack-in-a-box" rig. it covers all bands from 160m up through 70cm, all modes across AM/FM/SSB/CW, and of course has a wideband general coverage receiver as well (meaning, you can listen to shortwave stations, the local police, etc). this radio, like many of it's direct competitors, outputs 100W of RF on the HF bands, and about half that on the VHF/UHF bands. the 706MkIIg is small enough to be used mobile, but many folks use them for fixed station use. the control faceplate is removable and can be remotely mounted from the larger RF unit. the attached microphone allows FM and SSB (phone) voice modes; a key or paddle would be required in order to send CW (morse code). the automatic antenna tuner (box marked "LDG AT-7000" with no controls) is needed to help match the HF antenna's characteristic impedance at a given frequency to the radio's output impedance (nominally 50ohms). operation without the tuner is certainly possible, but it places more stringent considerations on the antenna employed and in most cases will limit the bands which can be used. this particular auto-tuner is controlled via a pushbutton switch on the radio itself; depressing the switch momentarily initiates a tuning cycle, during which the tuner spends a few seconds autonomously searching for a good match between the radio and antenna. when the tuning cycle is complete, the radio is ready to go for communications. (note: other types of antenna tuners are available; for example, some require observing a meter while manually manipulating of a set of dials to match the antenna to the radio at the desired frequency). the power supply (box marked "SEC 1223" with the power switch) simply takes 120Vac from the wall socket and converts it to DC at approximately 13.8Vdc. most all amateur radios are designed to accept 12Vdc nominal. the radio it powers requires about 20A DC input for full RF output; the power supply shown has an output rating of 23A, so there is approximately 10% headroom here. with a fixed station setup such as this, one can communicate locally using VHF/UHF, and nationally/globally using HF. i can't stress enough though that 7/8ths of the performance of this type of station is due to the antennas outside, and not the equipment on the desktop. the most expensive radio in the world is a paperweight without a good antenna system. note that similar setups can be constructed using Yaesu and Kenwood equipment. directly comparable to the Icom 706MkIIg shown is the Yaesu FT857D. in the case of some radios -- the Yaesu FT450, Kenwood TS2000, and Icom 746Pro come to mind -- the antenna tuner is incorporated into the radio itself. this saves some desk space, and in some cases may simplify operation to some extent. as you can see from one of the pictures, the HF output of the radio (upper RF connector) is umbilical'd to the antenna tuner via a short coax jumper, and the antenna itself would be connected to the tuner. in other words, the antenna tuner sits between the radio and the HF antenna. the VHF/UHF output of the radio (lower RF connector) would be directly attached to the outside VHF/UHF dual band antenna. there is a short, lightweight interconnecting cable between the radio and the antenna tuner that carries control signals. and finally, there is a heavy gauge cable that carries 13.8Vdc at high current from the power supply to the radio. while shown as a fixed station, this setup can be easily transported in a hard sided case. an enclosure with internal dimensions of approximately 8"H x 8"W x 12"D would be needed. the total weight of the three components shown in the pictures is approximately 10 pounds.         |
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ar-jedi
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Posted: 7/20/2008 12:16:56 PM
[Last Edit: 11/2/2008 9:20:35 PM by ar-jedi]
What is an Azimuthal Map and why do I need one? Originally Posted By A_Free_Man: We all know that conventional flat maps give a distorted view of theworld, especially as you get further north. It is difficult tounderstand why a flight from NY to London would pass over Greenland, ora flight from the US to Tokyo going over Alaska. The "Great Circle" andall that.
An "Azmuthal Map" places YOU, yes YOU at the center of your ownlittle universe where you properly belong. It redraws the map of theworld with your location at the center. You can more easily figure outthe proper heading for signals from you to whereever, how to aim yourantenna, and other nifty information. AR-Jedi can jump in here and tellus more about propagation, and how all this fits together so you canget that QSL card from that some little country most of us have neverheard of. So, where do I get one of these nifty maps? Here's one I found, afreeware, with a short Google search. It's called AZMap and you canread about it here: http://www.geocities.com/aa6z@sbcglobal.net/AZMapWeb.html Once you have it installed you'll have to find it in C:>ProgramFiles. It won't be listed in the menu. It will be in a folder calledAZMap. To get the program to open you'll have to double click on thefile AZMAP2.exe. I dragged it over to the start menu and made ashortcut there to add it to the menu. OK, start it up with a double click. Well, first thing you noticeis you are not the center of this universe. We can fix that. Go to QRZ.com and enter your call sign. When yout get to your page,click on Detailed Info. Now, write down your coordinates, Latitude andLongitude. Now back to AZMap... Look in that AZMap folder. You will find twofiles, Atlas1.txt and Locations.txt. Open them. These are simple textfiles, and you can add (put it in alphabetical order) your town, callsign prefix, and coordinates. If the first numbers (Latitude) ispositive, it is North, so use an N in the next column, then theLatitude rounded off to two decimal places. If the second number(Longitude) was +, you will enter E for east, and if negative, as itwill be for the US, enter w for West. Add a zero in front to makeLongitude a three digit number if necessary. Line up your columns withthe ones above and below. You can paste the same line you typed inAtlas1.txt into Locations.txt. You can also add friends towns andlocation info. Close and save. Now, go to File and open AZMap. Click File, Create New Map, andclick "Select from a List". Chose your location from the list and clickOK. You should now see a neat map with your location dead center. Seethe darker area? That is where the sun don't shine... no, not thatplace... places where it is after sundown. If you don't see it, in theMap Display Control Panel check "Show Terminator". This would be goodto know if you want to do try some "gray line" propagation. Over on the right in the Map Display Control Panel you can selectfrom a list. If you had entered your friends' locations in those filesI told you about earlier, you'd find them there. Or you can enter anyother Latitude and Longitude. Note the time display, click the Set TimeTo Now button, and time will be in UTC time, Zulu time, Greenwich MeanTime, or whatever is the flavor of the day. Over in the Map DisplayControl Panel check Auto-Update Time. Every so often you will see themap flash. That is the terminator line (sunrise, sunset) being redrawn. And when you enter your friends location in the Map Display ControlPanel you get a nice red line drawn from your place to theirs, and alittle arrow on the edge of the map showing you the heading. Anyway, a neat little program to add to your toolbox. |
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ar-jedi
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Posted: 7/20/2008 12:17:08 PM
[Last Edit: 1/8/2010 3:14:25 PM by ar-jedi]
I want a cheap, easy to use radio with long range... what do each of the following items have in common? –– unicorns. –– lower taxes. –– honest politicians. –– cheap, unlicensed, easy to use radios with long range. answer: none of them exist. so, if you are about to start a thread along the lines of the following... Originally Posted By xyz:
I am looking for suggestions on capable, 2 way communications that would be used primarily if the SHTF given that cell towers are not working, or just for use when traveling outside of cell coverage. I know from experience that the FRS and GFRS radios are complete crap. I am setting my budget at around $100 to $130 a radio. I want something with at least 10 mile (real miles, not line of sight) capability (if at all possible), handheld configuration (compatible with a base station add on later on), uses standard batteries (AA, C, whatever), and "somewhat" secure(in that Joe Blow cant walk into wally world, pick up a blister pack radio, and hear my communications) Originally Posted By xyz:
I was thinking at work to day if TSHTF How would people communicate? I have 2 radios from work so I would plan on giving one to my friend or fiance, but regular walkie talkies are good for what 100-500 yards on a clear day? I have tried the ones that say they are good for 3 miles and they don't work within a half a mile. Originally Posted By xyz:
I am not into cb radios or talking on ham radios. I really don't like to talk unless face to face. but i do know that i do need to be able to communicate or hear what is going on in the world and surrounding areas during shtf situations. so what are my options to cover this? Originally Posted By xyz:
I want a radio that doesnt require any license, gets 40-50 mile range in any terrain, and oh yeah, it has to be really cheap too. Originally Posted By xyz:
I wanna have more range than these junky little handheld radios you get at cabelas and dicks sporting goods for use when hunting or any situation where i might be further apart from someone i need to communicate with like a hunting buddy or whatever Originally Posted By xyz:
Looking for some suggestions on reliable, good walkie talkie type radios that could be found fairly cheap for SHTF type scenario. Just something the local like minded people could buy now and be able to talk in that kind of scenario. Like for a scouting party. Multiple radios on the same frequency or multi frequency radios. Older, used, whatever...as long as they work. Something I can find on Ebay? Originally Posted By xyz:
A few of us locals are taking steps to be ready if and when internet and cell phone comms go out. Can anyone recommend a good portable 2-way radio with a 20-mile range? Not looking for the Ham radio or anything with a huge antenna. Looking for something fairly reliable for mainly sporadic reports of things happening in our AO and to possibly arrange rally or bug-out points. ... the answer is "it's not straightforward." your options are, in approximate order of increasing cost, complexity, and performance:
Originally Posted By JBlitzen:
Depends on your budget, and on what sorts of communication are utilized in your area. Here are some good, and scattershot, rules of thumb to get you started: A good dual band ham radio can usually be modded to pick up, let's say, 80% - 90% of local communications, and transmit back on maybe 20% - 75%. Of course, your local police station may be in that last 10%, with a digital trunking system or something. You really have to know what's around you. A good scanner can usually pick up 90% - 100% of local communications, though it can't transmit at all. A mobile radio with a good antenna will always transmit better than a handheld, even if the handheld has a good antenna, because mobile radios usually support much higher power output. A mobile radio and a handheld radio, both attached to antennas of identical specs and positions, will usually receive equally well, since reception isn't really power based. As a corrolary of those two points, if you want to transmit rather than just receive, even (or especially) just in emergencies, then you want to focus on mobile or base radios, rather than handheld radios. The advantage over handhelds is at least an order of magnitude. The cheap Icom mobile in my truck maxes out at 55 watts, my yaesu handhelds max out at 5 watts. AM/FM broadcast bands are difficult to both tune into with any one ham radio, as they're so far apart on the RF spectrum. A good $10 am/fm radio will fill that hole in your listening needs. Local communications are usually VHF or UHF, which are, basically, line of sight, and work like FM broadcast radio. If you can see the antenna tower, you can hear the station. If there's a building in the way, you probably can't. Dual band usually refers to support for the 2 meter and 70 cm ham radio bands. 2 meter (144-148 mhz) is in the VHF range, and 70 cm (420-450 mhz) is in the UHF range, though it's not correct to say that 2 meter IS vhf or that 70 cm IS uhf, as the VHF and UHF ranges include a whole lot more than just those two ham bands. Thus, "dual band" isn't the same as "vhf/uhf". But, it's kinda close, and a lot of radio activity occurs within 50 mhz of one of those two bands. 800mhz has some public safety stuff (and a lot of the trunking public safety stuff), 200 mhz has a tiny bit of unencrypted military stuff, but most of what you'd actually want to listen to, except trunking public safety, will be within range of a dual band radio. Triband usually includes those two bands as well as 1.25 meters, which is kind of an odd, small, and low power band, which isn't used for a whole lot, and which isn't surrounded by much of anything interesting. Kinda, not much point. Quad band usually includes the same bands as a triband (2m, 1.25m, and 70cm), as well as 6 meter, which is an interesting band right on the edge of VHF, almost to HF. It's possible, under ideal conditions, to make long distance transmissions on the 6 meter band. Doesn't happen much, but it's very cool when it does. You certainly can't count on it for emergency use, though. There's some more interesting stuff around the 6 meter band than around the 1.25 meter band, but not a lot. Really kind of a niche band. One nice advantage is that quad band radios will sometimes support AM broadcast reception, and will often support FM broadcast reception. FM is around 100 mhz (when you tune in to 101.3 Warm Black Dude's Voice Cat Lady Radio, you're tuning to 101.3 mhz), which is usually out of reach of dual or triband radios as it's significantly lower than the designed 144.0 mhz lower limit. AM is around, seriously, 1 mhz. When you tune into 1180 WHAM Rush Beck News Radio, you're tuning in to 1.180 mhz. Note the decimal place. That's why you seldom find both of those bands on the same radio. The AM antenna has to be shoehorned in around all the other complicated shit, somehow without it being interfered with, and the FM broadcast band is in an engineering dead zone smack between the intended reception and transmit bands. Long distance communications are usually HF, which is weak enough that it can bounce off of our ionosphere and return to earth, rather than penetrating the ionosphere. That works like AM radio (which is actually medium frequency, lower even than HF, though there is a ham band there) (160 meters), where you can often hear stations at night that are not just counties but states or even countries away from you. And yes, standard HF ham radios can transmit at the same distances, although usually with lower power. One problem is that HF requires... patient... antennas. Which is to say, large antennas. Another problem is that HF requires a lot of power, since you're sending that signal way the hell up into lower earth orbit, bouncing it off of energy, and then sending it way the hell back down again, 1500 miles away. Bit more difficult than sending a cell phone signal to a cell tower 3 miles away. Thus, you never really see any portable HF radios. They're all mobile (designed to run off of high capacity vehicle batteries) or base (designed to run off of dedicated battery banks or AC power). Shortwave, AM, and HF, all work almost identically. CB is in that group, too, although CB equipment is legally so limited in power and capability as to be irrelevant, unless you happen to be trying to talk to someone with a CB, in which case it's the only way to fly. So, to fill out your communication niche, to listen to just about all communications, and transmit back on as many as possible, you'd want a mobile or base HF radio, a mobile or base VHF/UHF radio (possibly combined), a dedicated scanner or a very wideband VHF/UHF ham radio, and a simple AM/FM pocket radio for thsoe bands. To give you an idea of what that would cover: All ham frequencies All shortwave frequencies (listen only, with emergency transmit) All CB frequencies (listen only, with emergency transmit of dubious success) Aviation band AM broadcast band FM broadcast band Analog TV band NOAA/All Hazards frequencies FRS/GMRS frequencies All unencrypted public safety frequencies and bands Most unencrypted government frequencies and bands Most unencrypted military frequencies and bands (not satellite or ELF or stuff, of course) Most unencrypted private frequencies and bands (again, not satellite or whatever) Ambulances Police Fire Snowplows Stormchasers/Skywarn/RACES storm spotting Taxi services Buses Tow trucks Unencrypted 900mhz cordless phones Space shuttle International Space Station Amateur radio satellites Unencrypted federal agencies Unencrypted Air Force One Railroad Marine (boats n stuff) Coast guard Limited CB Things you wouldn't get: Military and commercial satellite frequencies and bands Encrypted communications Cell phones A couple other odds and ends. A special note about the Skywarn line in the above list of capabilities: many if not most tornado warnings originate from unencrypted ham radio transmissions from qualified storm spotters. If you have any interest in, or concern about, local tornadoes, hurricanes, or other severe weather, it is essential that you have the capability to monitor these transmissions, usually somewhere in the 2 meter band (144-148mhz). You will receive information about developing storms several minutes before the weather guy on TV does. Now, if you only had one radio per car, and you wanted to be able to get in touch with your wife, I would recommend a mobile radio with a good antenna for each. Handhelds are radically less effective than base or mobile radios, though of course are the only real option when outside of vehicles and away from a base station. If you can get mobile radios that support crossband repeat, that enhances your capabilities a little, by extending the utility of your mobile radios to a line of sight perimeter around the vehicles. A member of this forum was able to use that capability, after a hunting accident, to call for help while outside of cell phone calling area. He transmitted from his handheld radio, which relayed/repeated through his distant vehicle's mobile radio, which was able to reach someone who was able to alert the authorities and convey his location and status. If you can get mobile radios that support HF, that's really cool, and really fun, but adds nothing to your local capabilities, while compelling you to use a more complicated antenna system on the vehicles. On the other hand, *some* dual band VHF/UHF handheld ham radios make decent little scanners on their own. They can't track trunking conversations, but they can get pretty close, and can pick up most everything else. I like my FT-60R's for that purpose, though quad band radios have wider receive and transmit capabilities. Unfortunately, I'm not aware of any quad band radios that can run on high power from internal alkaline or lithium batteries. Additionally, the extra spectrum access really doesn't cover much of anything, except a small public safety band that isn't often used, and one or two other little things. My setup is an FT-60R handheld dual band as a portable radio/scanner, with an IC-208H mobile dual band VHF/UHF in my truck, and an IC-706MKIIG mobile HF/VHF/UHF as a base station usually packed in a pelican case. I started with the mobile radio, and I'm glad I did. I've never tested the range on it, but I can hit repeaters from 15 miles away in a city with no signal loss whatsoever. It can also pick up nearly all of the local public safety frequencies. As you can see, all of this kinda flies in the face of affordability. My starting radio was about $300, I think. And it doesn't support crossband repeat. A crossband repeat capable mobile radio would run somewhere around $400. A suitable antenna would be $50 to $75. Appropriate cable would be another couple bucks. Installing it is a chore, but you can do it yourself. Not much more difficult than installing a new car stereo and speakers and stuff. Almost any car audio installer will be happy to install ham equipment for a couple bucks. The Yaesu FT-8800R would probably be ideal for that purpose. If you want to go cheaper, and are only interested in communication with your spouse, and listening to other people, but never, ever, even if your spouse is on fire, being able to communicate to people you hear, then you could go with a single band mobile radio in each car, like an FT-1900R ($140 at universal radio) or an IC-2200H ($160), again with $40-$60 antennas each, for about $200 - $250 each car. Then get a portable trunking scanner for a little under $200, like a radio shack or uniden or something, to give you that listening capability. If you want to go even cheaper, then you can do handheld radios, like FRS/GMRS blister packs, but they tend to universally suck. They're okay if you're in a car following your spouse, but if the two cars get separated, because one gets lost, then you might easily wind up fucked. Unfortunately, handheld ham radios don't fare a whole lot better. There are unavoidable limitations when you compress a power supply and antenna into a device you can clip on to your belt. While it's true that you can plug handheld amateur radios into vehicle mounted antennas designed for handhelds (assuming the appropriate impedence; you probably can't pull that trick off with a cable and antenna designed for a mobile radio, since I believe they're 75 ohm, rather than 50 ohm that handhelds expect), you're still only transmitting at 5 watts max, and that's going to give you trouble. But, an FRS/GMRS blister pack set can be a good way to start feeling your way into radio communications. They're also usually much easier to use than ham equipment, because their capabilities are so very limited. That can make them more appealling to disinterested spouses. To give you an idea of what ham radios are capable of, if the above doesn't suggest it, consider these examples: 1. Severe storms are approaching your area. You set your portable ham radio to scan between the skywarn RACES repeater frequencies of three different counties; yours and two upwind of you. You listen to the storm spotters and the national weather service talk to each other about what they're seeing in person and on radar. You hear about a tornado sighting when it's five miles away. Two minutes later, the guy on the TV in front of you finally mentions that there's a tornado warning, but you already had that information, and had called your kids in from the yard. 2. You're out hunting, and you fall from your treestand and break your leg. You're unable to walk, three miles from your vehicle, twenty miles from town, and you can't get cell phone reception, so you request help via your portable ham radio, through your vehicle's powerful crossband repeat radio, to an area ham radio operator, who calls an ambulance for you. This, as mentioned elsewhere in this post, is basically what happened to a forum member here. 3. I go to a river lock for fun. Boats approach the lock. I take out my FT-60R, set it to smart search the marine band, and put it back on my belt. Two minutes later, I take it out again, and flip through the three results it found. One's a beacon, I can't figure out what the second one is due to there being no current traffic, but the third is the marine frequency that the lock uses to communicate with boats. I leave the radio on that, and listen in as the boats go through the lock cycle. If I had any reason to, I could press the transmit button and speak to both the boats and to the lock operator. Doing so would violate FCC rules, as the radio is not certified to transmit in the marine band. However, FCC rules also state that, in an emergency, I can use any damned means necessary to obtain help, which means that, if I fell down and broke my leg behind a bush, and I couldn't get cell reception and nobody responded to shouts, I would be legally permitted to hit that transmit button. Mundane, but a good example of the technical capabilities. 4. You swerve to miss a deer on the road. You end up running off the road into a tree, receiving light wounds in the process. The road isn't used much, it's six miles to a road that is, and you have no cell reception. Calling for help on your mobile radio obtains no answer from the local repeaters or the simplex emergency frequency. You scan through some public safety bands and immediately come across a state trooper communicating to his dispatcher about a traffic stop a couple miles away. You hit the transmit button and the dispatcher hears you. You inform them that you're a licensed amateur radio operator in a serious emergency. Maybe they yell at you, but they also send help. One last thing: it's important to remember that this is a broad overview. The capabilities and limitations of different radios within the same class, even if made by the same manufacturer, even if in the very same model series by that manufacturer, can and do differ *WIDELY*. On the universal radio site, in the mobile amateur transceivers category (we call radios like these ham radios "transceivers", as they can both "TRANSmit" and "reCEIVE", as opposed to your bedside alarm clock radio, or a shortwave radio, or a scanner, all of which only receive), I can see maybe four or five out of the 20 or 30 models that would be appropriate for casual and emergency use. For instance, digital radio is almost completely useless for your purposes, and that's what the more expensive radios usually are for. Also, the ability to modify a radio to receive, and, particularly, to transmit, outside of its intended capabilities, is vital. There are some very good radios around that simply can't be modified to have extended capabilities. That means that you're sitting there, listening to a car accident victim's screams, and listening, over the radio, to two police officers chatting on their intercar frequency at, whatever, 162.5 mhz, but you cannot talk to them because your radio only transmits between 144.0 and 148.0 mhz, and you can't raise any amateur radio operators in that band. When you see some of the Icom and Yaesu radios get mentioned, like the FT-60R, the VX-7R, the VX-6R, my IC-706, and some others, those can be modded very extensively. My 706 can essentially transmit on pretty much any frequency between 1.6 mhz and 54 mhz. Forget bands, it'll give me its best shot on literally any frequency in that range, with just a few patches for phase problems or whatever. Of course, power output and signal quality will degrade as you wander away from the designed specs, but it's a hell of a lot better than a "no tx" warning on the attempt. VHF/UHF are usually more restricted in capability due to engineering problems, but you can still open those radios up quite a bit, if they're designed for it. Other variations can be signal quality, reception quality, scanning capabilities (the Yaesu radios have a smart search capability that's breathtaking in its utility), power supplies (the FT-60R can run maxed out on humble AA's, while the VX-7R monster can only do so on internal rechargeable batteries with their logistical complexities, or on complicated external battery cases and straps; mobile and base radios are much thirstier for power, and require serious thought to their power needs, using RC, golf cart, or car, batteries), design ruggedness, interface complexity, cooling requirements, antenna connectors, mic/earphone connectors, etc. You definitely don't want to buy a radio just because the price is right, or because it looks cool. You really need to carefully review the specifications and accessories, research available mods, and read the reviews of that radio at http://www.eham.net/. Then, because those eham guys have their own interests, you'd want to come here or to a forum like zombie squad, where we're more conscious of the specific problems related to emergency use, and check with us. ps: Originally Posted By GlockTiger:
Stop looking for the quick fix, easy way out. This board is about preparedness. Actually preparing for something usually involves a little time up front. There's no quick fix in building a BOB or BOV or gardening or canning or investing or defensive training –– why must there be one for communications? You showed foresight by recognizing the need to communicate. Now that you have some direction on the subject, don't give up because you might have to invest some thought into it to achieve your objectives. We have an excellent learning environment for the topic of communications from a preps perspective –– don't shortchange us or yourself by throwing in the towel because you're intimidated by a topic that is new to you. |
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ar-jedi
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Posted: 7/20/2008 12:17:22 PM
[Last Edit: 2/6/2013 12:00:03 AM by ar-jedi]
Amateur radio for preppers... contribution from pilotman: Q. I'm looking for a solution for emergency communications from a preparedness standpoint. Is Amateur Radio the solution? A. Possibly. If you're willing to take some time to learn and experiment, you will probably find amateur radio a welcome addition to your preparedness plan. Q. That doesn't sound terrible. What do I need to buy in order to communicate with (whoever I want to communicate with)? A. If you're expecting a one size fits all "emergency communications kit, just add people you want to talk to" package, you are out of luck. What you need depends on many, many variables. Part of the process here is to be able to create a system that works best for you, how to set it up, and how to use it. Yes, you get to engineer your own system for your particular needs. If you're looking at this with preparedness in mind, this knowledge is invaluable. Q. OK, I'm still interested. How much? A. The answer here depends on what exactly you want to do. However, I would say a minimum of $200 is required. On the other end of the scale, you can be well equipped for $1500-$2000 if you do your research and purchase carefully. Q. That doesn't sound too bad. Can I just buy everything and stash it away? A. To be very blunt, if you're not willing to accept amateur radio as at least a part time hobby, I would say that it's not for you. Most amateur equipment is not "plug and play", and getting everything to work correctly requires a bit of study, practice and experimentation. To use an analogy, it's not like buying a fully assembled computer, rather it's more like figuring out what components will work for your desired application and putting everything together yourself. Neither are extremely difficult, however both require something of a commitment to learning. Q. Ok, so how much involvement? A. As with anything else preparedness related, familiarity with your equipment and supplies is essential. Regardless of what the advertisements and specs say, the only way to know how your communications system will work in real life is to use it. Getting on the air and making contacts lets you know exactly what your equipment will do. Things like building and setting up your own antennas let you see and experience the theory behind everything. I personally became involved as a way to expand my knowledge of electronics, and I've enjoyed that along with other facets of the hobby. The people you will meet and talk to have very diverse reasons for their involvement (spoiler: many hams are preparedness minded) -- something that comes as a surprise to many entering what is largely seen by the public as a "nerd" hobby. Q. I want to be able to communicate securely. What about encryption? A. The short answer: The FCC prohibits encrypted communications using the amateur spectrum. |
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ar-jedi
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Posted: 11/6/2008 8:56:50 PM
[Last Edit: 9/9/2011 6:23:15 PM by ar-jedi]
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ar-jedi
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Posted: 10/15/2009 10:33:31 PM
[Last Edit: 9/8/2011 11:21:45 PM by Paul]
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ar-jedi
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Posted: 8/5/2011 5:41:16 PM
[Last Edit: 9/9/2011 6:22:35 PM by ar-jedi]
PLEASE DON'T POST REPLIES IN THIS THREAD!!! folks, if you have a specific question or concern about the FAQ just IM me, or start a thread in the Ham Radio forum. thanks much. ar-jedi |
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