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Link Posted: 7/29/2006 4:12:27 PM EST

Originally Posted By jblachly:
What are the relative advantages and disadvantages of SSB ?

Why do radio stations use AM and FM rather than SSB?  Why do HAMs use SSB?

This may be more of a General question, even though I am studying for Technician I was very curious about this.

Thank you.


Gen or Tech aside, it's a great question and worth knowing regardless of class. SSB is common in the 6m and 2m bands (Techs have access). Here is some text slightly adapted from an email to an Arfcommer who asked a similar question:

When you get on HF airwaves you'll find that
G> AM is a poor mode for ham. It totally devours bandwidth, and we have a hard
G> enough time finding a quiet spot on 40m (because of foreign SW broadcasts at
G> night) and 80m (just always congested with ragchewers) -- if we were to move
G> to AM we would crap all over everyone else's QSO's -- where you need to leave about
G> 2-3 khz of space on each side of an ongoing SSB chat, AM kills more like 10-15khz. I know this because many foreign broadcast stations share the 40m band and their signals are all over the phone portion of the band at night.

G> Plus AM is highly inefficient, and most rigs max out about 40 watts on AM
G> (vs. 100 watts on any other mode). Remember it uses a carrier (useless power
G> expended, carries no intelligence) and 2 sidebands (upper and lower). Single
G> sideband uses a THIRD of that space. When transmitting AM, the reason the
G> max power is so low is much of it is wasted emitting all three components
G> vs. focusing the power on just one single sideband (upper or lower) or a
G> continuous wave (CW) signal.

Why do radio stations use AM & FM? Well, here's my best shot (I'm stretching my knowledge). Keep in mind SSB is sometimes referred to as "suppressed carrier," so the transmitter is actually starting with an AM signal and suppressing the carrier and one of the sidebands. You'll see the suppression stats in the specs listing for the transmitter. So I think AM is actually simpler to design in TX and RX -- you have to have more specialized equipment to receive it for sure. To buy a Shortwave receiver that is SSB capable, you spend almost as many hundreds of bucks as you would on a full featured Ham transceiver.

Other guys please fill or correct any inaccuracies in my synopsis.
Link Posted: 7/29/2006 6:03:42 PM EST
Good answer on the AM question.  I got the same IM...

ssb (and CW) are called "weak signal" modes.  Not because the signals leaving your rig are weak, but because a lot more people can hear you with a lot weaker sig at the recieving end.  

You've noticed, I'm sure, the phenomenon in FM listening where you can hear your favorite station as you're driving, but you hit a certain distance and it rapidly drops off, or another station comes in and out between your original station.  This is because FM works on what is called the "Capture Effect."  The signal strong enough to "capture" the receiver wins, and when you get out to the fringe, it drops off.

With SSB and CW, your signal goes out there and the receivers will hear it at much lower strength.  Also, with SSB, there is no "Capture Effect" and if two people happen to talk at the same time, instead of a winner, or totally unintelligible mixing, you can hear them both.

FM is also pretty wide.

In my opinion, brodcasters use AM and FM because they've never innovated.  FM has a nice audio quality for music, and AM has always been there.  Stereo AM actually gives FM a run for the money...  Not that I think commercial radio should go to ssb....


fwiw
Scott
Link Posted: 7/29/2006 6:24:18 PM EST

Originally Posted By speedracer422:
Ok, I've resaerched this as well as most people here and am still confused and overwhelmed w/ the amount of info. Add to that I just can't afford another expensive, addictive time consuming hobby, sooo....

Is it possible and practical and purchase a ham radio for ~$300-$400 w/o any expensive upgrades (i'm thinking a portable model) and actually talk to people reliably 100 to 200 miles away w/o the use of repeaters? How much better are hams than gmrs in woods and urban settings?

i.e.; can I really use ham radio as practical form of comms in an all out emergency?



These are the questions I myself really need answered and I'm sure others here do to.


FWIW, I've tried GMRS radios around town in my AO and found them (8 mile cobras and cheapo cina mart unidens) to be lacking. My 8 mile cobras won't even go more than 12 blocks (no building over 3 stories in between us either).


Speed


If you get your general or extra license so that you can use HF frequencies, you can buy off-the-shelf radios that will give you hundreds to thousands of miles of range with no additional technical work on your part.  

Jim
Link Posted: 7/30/2006 12:45:35 AM EST
[Last Edit: 7/30/2006 1:05:41 AM EST by FrankSymptoms]

In my opinion, brodcasters use AM and FM because they've never innovated. FM has a nice audio quality for music, and AM has always been there. Stereo AM actually gives FM a run for the money... Not that I think commercial radio should go to ssb....


fwiw
Scott


Great answers in your original post, Scott.

The only thing I'd add is,  the reason broadcasters still use FM and AM is more because there are many millions of receivers out there, and replacing them will have a major economic impact.

They ARE replacing the TV bands with digital TV in a few years; the electronic manufacturers are gearing up for digital TV, as well as converters for the existing TV receivers. The existing TV bands are bandwidth hogs; Channel 2 for example takes 2 or 3 MEGAHERTZ of bandwidth! So it is high time to make the switch.
Link Posted: 7/30/2006 12:54:27 AM EST

Originally Posted By Scottman:

Originally Posted By FrankSymptoms:

[dumb blush for stupid mistake]  For the distances you are talking about, 10 or 15  40 or 80 meters would be the band of choice.  [/dumb blush for stupid mistake]


I disagree completely.  You are right, I've corrected it.



BUT REMEMBER: When using the HF bands, the weather conditons rule. Sometimes it is possible to talk hundreds or even thousands of miles on a particular band, with very little power; other times it is difficult to get outside of your county. Weather conditions rule the (air)waves! I intend to write a short discourse about this sometime.


I've not heard that in over 20 years as a ham radio operator...  I can't wait to hear your discourse.

BTW, What is your experience frank?  


?? I am referring to the sunspot cycle, while trying to keep it on an elementary level for the sake of the newcomers. My experience includes all the pre-WARC HF bands above 160 meters, plus 2 m and 440 MHz.

My own favorite story involves overhearing a QSO from New York City, on 10 meters; the ham with the faintest signal said he was using 5 watts with a converted CB rig. (I was not able to contact him to let him know he was getting into California.) This was during the peak of the sunspot cycle, of  course; it was about the only thing that could have explained this feat.
Link Posted: 7/30/2006 3:36:03 AM EST
Check out this thread. Scottman is offering a Tech ham radio license course online!

ar15.com/forums/topic.html?b=1&f=123&t=485957
Link Posted: 7/30/2006 11:44:30 AM EST
alrighty then guys...when i read the thread topic and i got all excited!, was smashed into an insecure puddle of WTF. so now i ask, instead of HAM for dummies, which seemed to go ubertechie, especially for a guy who thinks in terms of nuts , bolts and a welder.  how about HAM for the ultra retard. yes, ME!   so, then before quoting ionispere, bouncing bettys and all this. why not....START HERE>  hey retard, buy THIS RADIO>  it is a great way to get started...then how to power it up, without burning it out.  yes, it sounds lame, but lets get back to the basic principal...not the best way to tune a antenna.  i dont know what radio to buy let alone where to plug it in , or build an antenna. hell i'd be happy to receive some static first!  shit, it would be like alexander bell, the first time he heard whats his face say " come in here "  if i picked up a signal, i might wet myself.       {kidding}  

  lets start with a dummie friendly list of radios, perhaps starting in the good radio at a good price geared towards better radios that are worth paying more for and WHY!...a list of shit to stay away from... kinda like the list of ammo,...the best being M193. the worst being olympic and then, EVERYTHING in between.

   please help me get going guys.   i think that i'd rather get a radio going then buy perhaps another shooter.    
Link Posted: 7/30/2006 11:52:42 AM EST

Originally Posted By FrankSymptoms:
They ARE replacing the TV bands with digital TV in a few years; the electronic manufacturers are gearing up for digital TV, as well as converters for the existing TV receivers. The existing TV bands are bandwidth hogs; Channel 2 for example takes 2 or 3 MEGAHERTZ of bandwidth! So it is high time to make the switch.


Yeah, so the gov't can sell the bandwidth!  lol....

And I agree on the millions of receivers too...

Scott
Link Posted: 7/30/2006 11:54:15 AM EST

Originally Posted By FrankSymptoms:

?? I am referring to the sunspot cycle, while trying to keep it on an elementary level for the sake of the newcomers.



Ok, I'm with ya there.  That's just not what I think of when ya say "Weather," but Ok, I get ya now.

Scott
Link Posted: 7/30/2006 12:22:30 PM EST

Originally Posted By nirvana:
alrighty then guys...when i read the thread topic and i got all excited!, was smashed into an insecure puddle of WTF.

lets start with a dummie friendly list of radios, perhaps starting in the good radio at a good price geared towards better radios that are worth paying more for and WHY!...a list of shit to stay away from... kinda like the list of ammo,...the best being M193. the worst being olympic and then, EVERYTHING in between.

   please help me get going guys.   i think that i'd rather get a radio going then buy perhaps another shooter.    


Please resist the temptation to just buy a radio. Instead of getting frustrated with those responding to questions on this board, please go buy The ARRL Ham Radio License Manual. This is the updated book (used to be called Now You're Talking for years). This will present the information in a logical way that a 6 year old can understand.

I learned everything I needed to both pass the Tech exam AND feel confident in my first radio purchase by checking out a copy of Now You're Talking and Ham Radio for Dummies from my library. Yep, free as the breeze and laid out better than any of us can by just responding to sporadic questions on these threads. If you're semi-serious, buy/rent this study guide and hopefully it'll get you fired up like it did me.

I have a buddy who went out and bought FOUR HT's, all different models and capabilities, before ever studying a lick for the exam. This resulted in frustration because he had 4 radios to learn and had no idea where to start. Just learn the basics from one of these published works and you will feel more confident.

Then when you're ready to shop (when you've passed your exam and waiting anxiously for that callsign to arrive), you can call up Gigaparts, Ham Radio Outlet, or other retailer and let their on-staff hams consult with you for your needs. I know HRO has very helpful folks for this. Even better, find someone from a local club to help. The best way to go is ONE ON ONE so you're not barraged from all sides like you're feeling here.

We ARFCOM hams can do a lot to help you, especially help you tailor your comms for a PREPS mindset (and not the hobby end of things), but you need to seek solid instruction if you're feeling this overwhelmed. ARRL materials are top notch, and there are others out there too.

That said, here are some handheld radios that seem to be prevalent here with ARFCOM'ers:
Yaesu VX-150
VX-170
FT-60R
VX-6R (what I have and love)
Yep, this list is all Yaesu. Yep, there are great offerings from Kenwood, Icom, and Alinco. Nope, I'm not going to list them cause I still believe shopping for radios now is putting the cart before the horse.
Link Posted: 7/30/2006 1:04:30 PM EST
[Last Edit: 7/30/2006 1:08:18 PM EST by Scottman]

Originally Posted By nirvana:
alrighty then guys...when i read the thread topic and i got all excited!, was smashed into an insecure puddle of WTF.


Sorry `bout that.  It's a big subject.

To just get your feet wet, get your Technician Class license, and buy one of these:

Yaesu FT-60R:


Yaesu VX-150


Kenwood TH-K2AT:


Icom IC-T2H:


ICOM IC-V8:


Or similar.  These are very basic, siomple rigs that cover the 2m band or the 2m and 70cm bands.  These are the most active VHF and UHF bands where you will get a taste for what you can do with your handheld.

If you want a more advanced, feature packed HT, look at these:

Yaesu VX-7R:


Kenwood TH-F6A:


Icom IC-T90:


These have vastly expanded recieve capabilities, I believe they can all cover from .5 Mhz (below AM broadcast) up to around 1 or 1.2 Gigahertz.  That is listening only.  They only transmit on 2M, 70cm, 1.25M (TH-F6A, low power on the VX-7R), and/or 6M (VX-7R and T-90A).

These are handheld radios that transmit in the bands that have a maximum range of about 20 miles under the very best conditions, so keep that in mind.

Now...
If you want something in the same frequency range, but higher power that can be used as a base-station or mobile, look at the mobile radios by each of those manufacturers.

Furthermore...
If you want to talk over long distances, you will need to get a General Class license.  With this license you can use portions of all the bands available to Hams.  Those bands do different things at different times, so you want a rig that covers all of them.

Some rigs cover all the HF bands, plus 2M and 70cm (the bands the above HT's cover).  These are nice all-purpose rigs.

The Yaesu FT-897:


Yaesu FT-857:


Yaesu FT-817:

(5watts only)

Icom IC-706MkIIG:


These radios are good enough to put on your desk as your base rig, or they can be taken mobile/portable.  With the exception of the FT-817, they're 100Watt rigs.  They are also "general coverage receivers," which means you can tune continuously from the bottom to the top and get the ham bands, as well as shortwave, military, etc.

With these radios, a simple wire antenna, and an antenna tuner, you can cover a lot of ground on HF.  You will need a seperate antenna for the VHF/UHF operation, but you can get one antenna to do both.

Here is my antenna feedpoint:


The top section, above the wire you see coming off the cross, is my helical antenna for 2M and 70cm.

The wire coming off the cross is the feedpoint for my 400 foot loop for HF.


Here is my base station gear:


On the left is the Yaesu FT-897.  It covers all HF bands, 6M, 2M, and 70cm.
On the right is my antenna tuner, which "matches" the antenna to the radio for best efficiency.

And here I am at the operating position:


Notice the TH-F6A on the shelf, next to the monitor.

In addition to that stuff, I have the predicessor to this rig riding in my van:


Mine does 60 Watts on 2Meter only.


Hope this is helpful
But study and get your license first!
Scott
Link Posted: 7/30/2006 1:07:52 PM EST
I would like to roll my earlier thread here for reference.
basics
Thanks a ton.
Link Posted: 7/30/2006 3:04:53 PM EST
[Last Edit: 7/30/2006 3:06:05 PM EST by KG5S]
Ok there seems to be alot of confusion on this HAM thing.............let me tell all the non ham guys that  .00000001% of hams know everything about this hobby and when we got into this hobby we knew about the same as you guys do right now but we still wanted to play so most of us went into to it blind, not knowing anything and the more we read and learned from others the more fun we had and you will to !

Good Luck

KG5S

users.ipa.net/~kg5s/
Link Posted: 7/30/2006 3:53:11 PM EST
[Last Edit: 7/30/2006 3:56:49 PM EST by Scottman]

Originally Posted By KG5S:
users.ipa.net/~kg5s/



daaaaaaaaaaaaaaaaaaaaaaaaa­aaaaammmmmmmmmmmmmmmm!

Nice shack!  Sheeit!

Well, there are the ends of the spectrum, folks!  lol.  a multi-tool shack and a shack that has lots of nice, specialized equipment, antennas, etc.

Damn Drew....gotta clean the drool off my desk!

Scott
Link Posted: 7/30/2006 7:35:34 PM EST
[Last Edit: 7/30/2006 8:00:23 PM EST by JaxShooter]

Originally Posted By Scottman:
The Yaesu ht's with 6 meters and an aftermarket antenna might clear that mountain.  If you have any local hams around that might be able to do some testing, that would shed some valuable light on the matter.

just a thought.


I don't know about this. Everything I've read is that the 6M sucks. I know it's not full power. It's either 1 or 1.5W instead of the 5W you get on 2M/440.

nirvana, I just went through the HT selection process and ended up with the Yaesu FT-60R. I compared it with the -6R and -7R but opted for it for several reasons. The primary driver was, admittedly, price. While I think it would be nice at times, I don't think I'll be in the environment enough that I need the radio to be submersible. If I'm out in the rain I'm hoping I'll have a poncho or something so the radio won't be getting soaked.

I also decided based on the reviews that the 6M option as I mentioned above wasn't compelling enough to purchase. I also didn't need features like the barometric sensor. There were things I would have liked, though, like the wider receive spectrum and the dual-band receive of the -7R.

HTH.

TheOtherDave, not sure why the QRZ site says Feb 06 for the test pool for Technician since the new pool started 7/1, but it does look like the new pool. fwiw:
You have passed the test with a score of 100.0 percent.

Other sites I'd recommend are www.radioexam.org and www.aa9pw.com. Unfortunately eHam.net hasn't updated to the new pool yet. Of course, you can download the entire question pool in various formats directly from ARRL.
Link Posted: 7/30/2006 8:11:26 PM EST

Originally Posted By JaxShooter:

Originally Posted By Scottman:
The Yaesu ht's with 6 meters and an aftermarket antenna might clear that mountain.  If you have any local hams around that might be able to do some testing, that would shed some valuable light on the matter.

just a thought.


I don't know about this. Everything I've read is that the 6M sucks. I know it's not full power. It's either 1 or 1.5W instead of the 5W you get on 2M/440.


Well...
Utilizing a reliable FET power amplifier circuit, the VX-7R provides a full 5 Watts of power output on the 50, 144, and 430 MHz Amateur bands, with bonus coverage of the 222 MHz band at 300 mW (USA version only).
Yaesu site.

But I still don't know how well it would do.  Would be interesting to test tho...

Scott
Link Posted: 7/30/2006 9:04:54 PM EST
I'm sorry. I meant the 220 on the -6R, not the 6M on the -7R. It's the 220 that was getting a bum rap.
Link Posted: 7/30/2006 11:44:53 PM EST

Originally Posted By Scottman:

Originally Posted By FrankSymptoms:
They ARE replacing the TV bands with digital TV in a few years; the electronic manufacturers are gearing up for digital TV, as well as converters for the existing TV receivers. The existing TV bands are bandwidth hogs; Channel 2 for example takes 2 or 3 MEGAHERTZ of bandwidth! So it is high time to make the switch.


Yeah, so the gov't can sell the bandwidth!  lol....

And I agree on the millions of receivers too...

Scott


My info says the bandwidth is already assigned... mostly to the cell phone companies, for digital TV/etc usage. Hard to believe it's ALL gone that way though.

Link Posted: 7/31/2006 12:38:50 AM EST
Do any of you have Cb's or HAM radios in your rides?
If so whats a good setup?
suggestions, and pics are cool

I don't really want to buy one till I know whats the different with the bands, whats most popular, I saw the ones listed above.  but I don't know enough to figure out what to get to start. Let me just say I have a truck, I would like to use it in a boat, and able to hike it if needed.  If I get a handheld, can I make a setup in my truck to boost the signal, and hook it to a mounted antenna, make a docking station for it? oh, and I already have a threaded mount for an antenna on the top of the truck rear of the roof rack.
If that was my plan what of the band/ combination of bands below should I get?
For that scenario would a mobil station be better than a handheld?

sorry if its to much info or not enough, I'm just getting into it.


1.25M RADIOS
2M RADIOS
70CM RADIOS
HF/6M/VHF/UHF
1.2GHZ RADIOS
6M RADIOS
HF/6M RADIOS
VHF/UHF RADIOS
Link Posted: 7/31/2006 1:53:07 AM EST
height=8
Originally Posted By GlockTiger:

That said, here are some handheld radios that seem to be prevalent here with ARFCOM'ers:
Yaesu VX-150
VX-170
FT-60R
VX-6R (what I have and love)
Yep, this list is all Yaesu. Yep, there are great offerings from Kenwood, Icom, and Alinco. Nope, I'm not going to list them cause I still believe shopping for radios now is putting the cart before the horse.


OK, but I still don't know what the hell with the difference between
HIGH-SPEC 5-WATT 144 MHZ
2M Band
2M/70cm Band Handheld Radio
2M/70cm Band
Link Posted: 7/31/2006 5:06:52 AM EST

Originally Posted By Nolan1964:

Originally Posted By GlockTiger:

That said, here are some handheld radios that seem to be prevalent here with ARFCOM'ers:
Yaesu VX-150
VX-170
FT-60R
VX-6R (what I have and love)
Yep, this list is all Yaesu. Yep, there are great offerings from Kenwood, Icom, and Alinco. Nope, I'm not going to list them cause I still believe shopping for radios now is putting the cart before the horse.


OK, but I still don't know what the hell with the difference between
HIGH-SPEC 5-WATT 144 MHZ
2M Band
2M/70cm Band Handheld Radio
2M/70cm Band


"High Spec 5 watt 144 mhz" refers to a radio, probably a handheld, that operates in the 2 meter (144-148 mhz) band.

The 2m (2 meter) band is the common name for the most popular frequency range for handheld/mobile local communications, which spans from 144 to 148 mhz.

70cm (70 centimeters, or 0.7 meters) is the common name for another frequency range commonly used for local handheld/mobile communications, which spans from 420-450 mhz.

The bands, which you can see in more detail here at ARRL, are generally internationally agreed upon limits for amateur operations.  Not all nations or regions use exactly the same band limits, but they are fairly similar.

Jim
Link Posted: 7/31/2006 5:57:15 AM EST
New guys -- please check out the linked thread MOS2111 posted above. Then click the links Vector_Joe posted on that thread.

That might help prevent reinventing the wheel a bit here. I went back through some of those posts and lots of good stuff.

For one thing, Vector_Joe's Comms Primer PDF explains a little about the amateur bands (and how they're expressed in either frequencies -- like 144 Mhz, or wavelength -- like 2 meters).
Link Posted: 7/31/2006 7:51:54 AM EST
I found a nice, informative ham-related site this morning:

Athens Amateur Radio Club.
Link Posted: 7/31/2006 9:03:01 AM EST
My local club that I started !
www.ncaars.org/
Link Posted: 7/31/2006 10:21:58 PM EST
obligatory ar-jedi portable comms/equipment pictures...


icom 703+ HF/50MHz QRP rig (10W) with roll up dipole and 12V/12AH AGM battery:




icom 24AT dual band (2m/70cm) HT (circa 1991) shown with AA battery pack removed:




TinyTrak3 APRS and GPS receiver mounted in small enclosure:




my RACES portable comms box, incls 2M and HF/50MHz radios with 24AH of battery capacity AND integral AC->DC power supply:







full RACES box construction details are here: (older pics though, HF/50MHz radio was added later)
losdos.dyndns.org:8080/public/ham/RACES-box.html


daily work bag includes Yaesu VX6R and two antennas, one OEM duck and one micro duck:






bug-out-box for truck includes Icom 24AT, lithium AA batteries, alkaline AA batteries, 12V cig lighter adapter, and several antennas:








73,
ar-jedi

Link Posted: 7/31/2006 11:22:52 PM EST
thats what I'm talking about... f*ing cool setups!
Link Posted: 8/1/2006 7:18:08 AM EST
Antenna height is important, especially for VHF and UHF.  You don't need a gigantic tower but getting your radiator up in the air really improves your ability to communicate with people further away.  Doing so gets the antenna above a lot of things that will block your signal.

Case in point:  When I got my ticket last year I was able to hit a 2M repeater about 13 miles away from inside my house, using a Yaesu VX-5 on 5W, with a J-Pole made from some Romex.  After a few months I'd be able to hear that repeater but it couldn't hear me.  I still couldn't hit the repeater with a mag mount antenna sitting on my wife's car in the driveway, using my Yaesu FT-7800R at 20W.  Something must've gone up in between us and was blocking my transmissions.

The day before yesterday I was able to (after much waiting) mount a Comet GP-3 antenna on a 5' mast up on my roof.  The tip of the antenna is probably about 30' above ground level.  Last night I was able to get on the same repeater and was heard clearly using the FT-7800R at 20W.

I'm tempted to add another 5' section of mast to get me a little more range but I'll see what I can do with my existing setup.
Link Posted: 8/1/2006 11:15:07 AM EST

Originally Posted By GlockTiger:


That said, here are some handheld radios that seem to be prevalent here with ARFCOM'ers:
Yaesu VX-150


+ 1
Link Posted: 8/1/2006 12:45:18 PM EST
[Last Edit: 8/1/2006 12:56:31 PM EST by JaxShooter]
Thx for the pix jedi. How long does that battery last? Have you been using APRS long? Just heard a cool story about it. A guy's vehicle was stolen but apparently he had the radio and GPS on. He went online and found his vehicle and called the cops. They didn't believe him that he knew exactly where it was, but he explained how and the dispatcher called for any units in the area he specified. Sure enough there was a car matching his description and the thief was arrested. How cool is that? Yet another reason for a radio!

Man, I just skimmed your page and it's awesome! Can't wait to get home and read it in detail. Thanks for sharing!
Link Posted: 8/1/2006 5:09:59 PM EST
Hey, AR-Jedi, what GPS receiver is that?  I've been looking for one to do the same project, I'll use a tiny trak, a small discrete GPS receiver, and a used 2m mobile or even handheld to put APRS in my car.

Jim
Link Posted: 8/1/2006 5:20:42 PM EST
[Last Edit: 8/1/2006 5:22:29 PM EST by ar-jedi]

Originally Posted By KS_Physicist:
Hey, AR-Jedi, what GPS receiver is that?  I've been looking for one to do the same project, I'll use a tiny trak, a small discrete GPS receiver, and a used 2m mobile or even handheld to put APRS in my car.

Jim


jim,
it's a single board OEM GPS called an Axiom Sandpiper II that i bought off ebay more than a year ago.  it outputs NEMA sentences at 4800 baud 8N1 with RS232 levels and is therefore a direct, no-glue interface with the TinyTrak.  note: antenna not included.

here is my bookmark with all of the tech info:
www.allsurplus.net/Axiom/

here is a current ebay sale:
mega long ebay link
(if the ebay link expires, go to here, scroll down in the left side panel, and click on "Purchase".

hope that helps.  my usual setup is a TT3, this GPS + a 5Vdc regulator (it's mounted to a metal strip in the pic i linked to above, a GPS antenna that i had laying around, and a Yaesu VX170 2M HT.  

ar-jedi


Link Posted: 8/1/2006 5:27:45 PM EST
[Last Edit: 8/1/2006 5:31:11 PM EST by ar-jedi]

Originally Posted By Surf:

Originally Posted By GlockTiger:
That said, here are some handheld radios that seem to be prevalent here with ARFCOM'ers:
Yaesu VX-150

+ 1


the VX170 is a better HT, in several respects, IMHO.  it's well worth the extra $30.

+ submersible
+ 700 mW of audio
+ 1400 mAh battery
+ preprogrammed weather frequencies with severe weather alert.

ar-jedi

Link Posted: 8/1/2006 6:04:09 PM EST

Originally Posted By Nolan1964:
Do any of you have Cb's or HAM radios in your rides?
If so whats a good setup?
suggestions, and pics are cool

I don't really want to buy one till I know whats the different with the bands, whats most popular, I saw the ones listed above.  but I don't know enough to figure out what to get to start. Let me just say I have a truck, I would like to use it in a boat, and able to hike it if needed.  If I get a handheld, can I make a setup in my truck to boost the signal, and hook it to a mounted antenna, make a docking station for it? oh, and I already have a threaded mount for an antenna on the top of the truck rear of the roof rack.
If that was my plan what of the band/ combination of bands below should I get?
For that scenario would a mobil station be better than a handheld?

sorry if its to much info or not enough, I'm just getting into it.


1.25M RADIOS
2M RADIOS
70CM RADIOS
HF/6M/VHF/UHF
1.2GHZ RADIOS
6M RADIOS
HF/6M RADIOS
VHF/UHF RADIOS


Good place to start with the next 'factoid of the day.'

Sometimes you will hear hams talking about the 40 meter band... sometimes they will talk about the 7 MHz band. The first term is the WAVELENGTH, and the second term is the FREQUENCY.  These are two different ways of talking about the exact same thing!   Usually, like 99.9999 percent of the time, when you are talking about the wavelength, you are talking about the band, which is a range of frequencies; when you are talking about the fequency, you refer to the specific frequency within a band. So a ham will talk about "I met so-and-so on the 40 meter band, on 7.125 MHz."

So where did the different usages come from? "Back in the days" when radio was in its infancy, operators DID use the wavelength to describe the frequency! So here's where it comes from:

If you transmit on any fixed frequency, the radio wave you transmit actually has a physical length in space! So a 7.5 MHz wave is exactly 40 meters long. This comes from the mathematical equation [300 / wavelength] = (frequency in MHz).

The actual usage of the "XX meter band" is rather archaic, but it is a part of the history of ham radio, and it's here to stay!
Link Posted: 8/1/2006 6:39:25 PM EST

Originally Posted By Nolan1964:
Do any of you have Cb's or HAM radios in your rides?
If so whats a good setup?
suggestions, and pics are cool


Icom V8000 2M in my Tacoma.  antenna is NMO mount Comet 2m/70cm.  

ar-jedi












Link Posted: 8/1/2006 8:21:09 PM EST

Originally Posted By ar-jedi:

Originally Posted By KS_Physicist:
Hey, AR-Jedi, what GPS receiver is that?  I've been looking for one to do the same project, I'll use a tiny trak, a small discrete GPS receiver, and a used 2m mobile or even handheld to put APRS in my car.

Jim


jim,
it's a single board OEM GPS called an Axiom Sandpiper II that i bought off ebay more than a year ago.  it outputs NEMA sentences at 4800 baud 8N1 with RS232 levels and is therefore a direct, no-glue interface with the TinyTrak.  note: antenna not included.

here is my bookmark with all of the tech info:
www.allsurplus.net/Axiom/

here is a current ebay sale:
mega long ebay link
(if the ebay link expires, go to here, scroll down in the left side panel, and click on "Purchase".

hope that helps.  my usual setup is a TT3, this GPS + a 5Vdc regulator (it's mounted to a metal strip in the pic i linked to above, a GPS antenna that i had laying around, and a Yaesu VX170 2M HT.  

ar-jedi




Wow, that is perfect.  The specs call for an active antenna; I have a Vaisala radiosonde with gps unit; the GPS unit is not useable (doesn't do calculations, just transmits offsets) but the part of the board that IS useable is the preamp and the quadrifiliar antenna.  

Jim
Link Posted: 8/1/2006 8:54:13 PM EST

Originally Posted By KS_Physicist:
The specs call for an active antenna; I have a Vaisala radiosonde with gps unit; the GPS unit is not useable (doesn't do calculations, just transmits offsets) but the part of the board that IS useable is the preamp and the quadrifiliar antenna.  


yes, any GPS antenna with an integral preamp should work,  note that there is an option on the board for strapping the phantom power for the preamp to either +3Vdc or 5Vdc.  the "older" active antennas use 5Vdc, the newer ones typically use 3V.  

the above linked unit has performed very well.  i will advise one thing...  as you may be aware, some aspects of the satelite ephemeris data are transient; that is, they are lost when the unit is powered down and new raw data must be received and then reprocessed at next power up.  this is a major contributor to "cold start" time.  however, there is a "hot start" which requires that the satelite ephemeris data be retained during power down.  by connecting a large cap (think "supercap", the 0.5F to 1F 5V variety) between pin 3 of the GPS (Vbat) and ground, the static RAM that holds the satelite ephemeris data will be held over for a long time (many hours).  this will enable very rapid starts (< 8 seconds) after which time GPS position data is fully valid.

good luck with your project.

ar-jedi

Link Posted: 8/1/2006 9:20:01 PM EST
[Last Edit: 8/1/2006 10:15:43 PM EST by CaptSchofield]
Originally Posted By Nolan1964:
Do any of you have Cb's or HAM radios in your rides?
If so whats a good setup?
suggestions, and pics are cool

Yaesu FT7800 dual (2M & 440) band. Face mounted in 2005 Chevy Trailblazer. Actual radio is under front seat. Velcro works great for hanging microphone, leaves no holes. External speaker is mounted at the back of the console



and a electric up/down antenna from Comet/Maldol mounted to roof rack. Antenna is a Jetstream 5/8 wave center fed


Link Posted: 8/2/2006 2:44:40 AM EST
height=8
Originally Posted By ar-jedi:
height=8
Originally Posted By Nolan1964:
Do any of you have Cb's or HAM radios in your rides?
If so whats a good setup?
suggestions, and pics are cool


Icom V8000 2M in my Tacoma.  antenna is NMO mount Comet 2m/70cm.  

ar-jedi

losdos.dyndns.org:8080/public/ham/tacoma-icom-v8000/DSCN1592_sm.jpg

losdos.dyndns.org:8080/public/ham/tacoma-icom-v8000/DSCN1597-annotated_sm.jpg

losdos.dyndns.org:8080/public/ham/tacoma-icom-v8000/DSCN1581_sm.jpg

losdos.dyndns.org:8080/public/ham/tacoma-icom-v8000/DSCN1588_sm.jpg

losdos.dyndns.org:8080/public/ham/tacoma-icom-v8000/DSCN1608_sm.jpg




About how much was all that? Whats the range with the antenna?
Where did you buy it from?

thanks
Link Posted: 8/2/2006 2:57:10 AM EST
height=8
Originally Posted By CaptSchofield:
Originally Posted By Nolan1964:
Do any of you have Cb's or HAM radios in your rides?
If so whats a good setup?
suggestions, and pics are cool

Yaesu FT7800 dual (2M & 440) band. Face mounted in 2005 Chevy Trailblazer. Actual radio is under front seat. Velcro works great for hanging microphone, leaves no holes. External speaker is mounted at the back of the console

i1.tinypic.com/21o1pgl.jpg
i4.tinypic.com/21o0od5.jpg
and a electric up/down antenna from Comet/Maldol mounted to roof rack. Antenna is a Jetstream 5/8 wave center fed
i5.tinypic.com/21o0x76.jpg

i1.tinypic.com/21o107b.jpg


so whats the difference between the antennas freq ranges and radio freq ranges?
Icom V8000 2M in my Tacoma. antenna is NMO mount Comet 2m/70cm.
and what you have...
Yaesu FT7800 dual (2M & 440) band
Antenna is a Jetstream 5/8 wave center fed

thanks guys

Link Posted: 8/2/2006 7:09:50 AM EST
[Last Edit: 8/2/2006 7:18:19 AM EST by ar-jedi]

Originally Posted By Nolan1964:

Originally Posted By ar-jedi:

Originally Posted By Nolan1964:
Do any of you have Cb's or HAM radios in your rides?
If so whats a good setup?
suggestions, and pics are cool

Icom V8000 2M in my Tacoma.  antenna is NMO mount Comet 2m/70cm.  


About how much was all that?
Whats the range with the antenna?
Where did you buy it from?

thanks


first, please read the entirety of the four or five posts below,
and also read
cynthion.com/survival_communications_primer.pdf
especially pages 4, 5, and 6 which relate to VHF frequencies, radios, and repeaters.

the radio shown in my pics above is a 2M VHF FM rig (TX from 144-148MHz), with 75W output on the max setting.  you can use it "simplex" (my radio to your radio direct) or you can use it in conjuntion with a repeater (my radio to repeater to your radio).  the antenna shown is a ~19" high 1/4wave.  it is an "average" antenna from a gain perspective.  there are larger "better" antennas, and there are shorter "worse" antennas.  there is no "free lunch" in antennas, size is everythiing.  one other aspect is directionality, i.e. using a beam type antenna to focus the RF in the direction of interest.  however, this is not practical for a mobile application, you need to use a unidirectional antenna.

with this setup, simplex range is highly dependent on terrain (flatter=better, higher=better), but i've done 30-40 miles many times before to VHF bases.  with a repeater, range can be much farther.  i can hit the Carmel, NY repeater from my home on the coast of NJ, and talk into NH on this system.  generally, though, i am using a 5W setting on the radio to talk into my local repeaters and chat with folks there, or using the 10W setting and talking into our county RACES repeater.  

ar-jedi


Link Posted: 8/2/2006 7:11:07 AM EST
here is a start at a soup to nuts ham primer:

i'll take a shot at this, and provide some links as well since my fingers would fall off before i could type everything you might want to know.

the usable-for-communications electromagnetic spectrum spans a frequency range from about 100KHz to 100GHz. (aside, only a portion of that is usable by inexpensive equipment). in the USA, the federal communications commission (FCC) is responsible for administering the spectrum for US users; however, the FCC works closely on this with international bodies, for reasons which will soon become clear. the "administering" that the FCC performs includes dictating what frequency bands are to be used for what purposes, and also specifying operational requirements for those bands (e.g. TX power output, ERP, modulation type, etc).

since examples are worth thousands of words, i'll provide a few. 1) the FCC has decided that broadcast FM stations are to exist in the 88MHz to 108MHz range. there are certainly power limits however i've no idea at hand what they are. 2) the FCC has decided that CB exists at around 27MHz, and that the maximum TX power output is 4W. 3) the FCC has decided that FRS exists around 462/467MHz, with a maximum ERP specified. and for the last example, 4) ham (amateur radio) has a number of bands allocated, each with associated limitations on power/modulation etc. i could go on and on with cell phones, marine radios, garage door openers, keyfobs, microwave towers, etc etc etc. basically, if the device is what is referred to by the FCC as an "intentional radiator", they have an assigned slot (band) for it and constraints on it's operation.

why the constraints? well, one reason is for your physiological protection. high RF power can cause burns, blindness, and other problems. (the "invention" of the microwave oven was an accident -- technicians working on early radar antennas were developing burns when the units were powered). another reason for the constraints is public safety. the last thing a 747 pilot on emergency approach into Kennedy airport needs is crosstalk with taxi dispatchers in NYC. hence the wide berth the FCC gives around police, fire, and EMS frequencies.

now then, we see that the FCC regulates intentional radiator use by dividing the frequency spectrum into bands, and then sets characteristics for each of those bands that users must obey by.

a common question is, "is one frequency band 'better' than another"? the answer is "sometimes". for certain applications (more on this in a moment), a given frequency band may provide better range, fidelity, immunity to interference, and so forth. these factors, and others, that make a frequency usable for a given application were taken into consideration when the spectrum was allocated.

it is important to note here that transmitter power output is one of many, many factors that influence the range at which you can communicate over a given transmission path. while important, transmitter power output plays only one role in a multi-faceted problem. antenna gain, antenna polarization, modulation type, receiver sensitivity, background noise level, path loss, and a dozen other issues factor into the equation. show me a well designed 2W transmitter and i will show you a way to communicate ~6.5 billion miles. NASA does this every day with their Voyager 1 & 2 probes -- they are now twice as far away as Pluto.

you wanted to talk about ham radio, so now that you understand a little of the background we can move on.

to simplify things, amateur radio communication can be thought of in two segments: HF and VHF/UHF.

first, i hate to break this to you, but THE EARTH IS ROUND. no, i'm not kidding -- it really is spherical despite what they told you in school or at church. ok, now that you are past that, you should visualize in your head that radio waves travel in a straight line. since the earth curves, it is not possible to talk over distances of over about 20 miles without "help". this "help" can come in a multitude of ways, and is somewhat dependent on the height of the transmitter and receiver, the gain of their respective antennae, the frequency of transmission, the weather and other atmospheric conditions, the sun cycle, hams around you erecting things called repeaters, and a few dozen other things. nevertheless, the key point here is that the further you are away from each other, the more likely it is that the curvature of the earth is going to be the limiting factor. always remember that without "help", radio communications are "line of sight".

HF, or high frequency (roughly defined as everything below about 30MHz [10 meters wavelength]) signals can bounce off of a charged belt (called the ionosphere) which completely envelopes the earth. HF thus can communicate over long distances by using one or more "bounces" -- you may have heard the CB term "skip". with just a few dozen watts, and a proper antenna, it's possible for you to talk (or more likely communicate using morse) with a station 2000 miles away. interestingly, it is sometimes difficult to talk to nearby stations that are "under the skip", that is they are too close to you to hear the reflected wave. one primary disadvantage of HF communications is that the antenna has to be physically long. nevertheless, HF can be a valuable asset in emergency commications -- like it was during hurricane katrina when everything else was tits up. in general, when you think of HF you should think of long distance comms. with some exceptions, most HF rigs are designed for desktop use and the supporting equipment (power supplies, antenna tuner, etc) is heavy and not so portable. but there is a class of mobile and low power HF rigs which allow you to talk over great distances with just a few pounds of equipment.

aside: there is an entire "sub-culture" within ham radio of people dedicated to QRP, or long distance very low power communications. hundreds or thousands of miles on 5W, 1W, or even 0.5W is their goal. antenna selection and a good idea of what the ionosphere is doing are prerequisites.

VHF/UHF, or very/ultra high frequency (roughly defined as everything above about 50MHz [6 meters wavelength]) signals do not bounce off of the ionosphere. hence, VHF/UHF is pretty much "line of sight" except for some atmospheric effects which occasionally allow communications to take place out to a few hundred miles. these effects can not be "scheduled" though, mother nature has her own clock. in other words you can not depend on these phenomena for reliable communications. when you think of VHF/UHF you should think of short distance comms. amateur radios in the 6M (50MHz), 2M, (146MHz), 1.25M (220MHz), and 70cm (440MHz) bands are examples of VHF/UHF equipment. hand held radios in these bands are knowns as "HT's", or handy talkies. of course there are mobile and base versions as well that sport more output power or additional capabilities.

continuing on, FRS (UHF, ~462/467MHZ) and GMRS (UHF, same) are examples of inexpensive general purpose you-don't-need-a-ham-license radios. most commercial radios (tow trucks, florists, plumbers, Amtrak, mall ninjas, etc) operate in the 150MHz VHF band. and until somewhat recently, most public safety (police, fire, first aid) were in the 150MHz and 450MHz bands as well. however, within the last 5 years many have migrated to the 900MHz band using what are called trunked radio systems. long story there but trunking allows a lot of flexibility for the system. you'll note that VHF/UHF radios are cheap, small, have short antennas, and long battery life. moreover, amateur VHF/UHF radios double as scanners for the public service and other frequencies as well. the most popular VHF/UHF "band" is 2M, or about 146MHz. there is a reason for this... read on...

Link Posted: 8/2/2006 7:11:38 AM EST
as noted above, the primary limitation of VHF/UHF is the short range imposed by the curvature of the earth combined with the fact that VHF/UHF signals do not bounce off of the ionosphere (in case you were wondering, they pass right through it). of course it helps greatly with VHF/UHF to be up as high as possible, as this gives more "line of sight" distance -- the same way you can see much farther when atop a tall building. but that's not always practical. e.g., i live right at sea level -- no kidding. how can i, the low lying ham, communicate with any distance using VHF or UHF? am i stuck trying to use HF for comms more than a few miles?

enter the "repeater". simply put, a repeater is an unattended radio advantageously located on a hill or with the antenna high up on a tower. the purpose of the repeater is to retransmit your signal in real time. it does this by listening on one frequency, called the input, and simultaneously transmitting the input audio on a second frequency, called the output. accordingly, my radio would be set to transmit on the repeater's input frequency, and listen on the repeater's output frequency. (the difference is known as the "offset".) all that is required from a radio implementation standpoint is a little bit of frequency agility -- when you press the transmit button, your radio tunes it's transmitter to the required new frequency. when you unkey, it changes back. all this happens in milliseconds and without your involvement save for some initial settings. the beauty of this set up is that with a low power HT (typ, 0.5W to 5W) you can talk for perhaps hundreds of miles! the repeater provides the "help" for VHF and UHF, just like the ionosphere provided the "help" for HF.

ham radio clubs set up, operate, and maintain repeaters. there are likely several repeaters reachable from where ever you are reading this from. from my home i can reach about 8 repeaters, of course i do live near a metro area with a high population density. note that there are published books of public amateur repeaters, which denote their location and characteristics (e.g., output frequency and offset). the reason that 2M/146MHz radios are so popular and inexpensive is simply due to the fact that there are more repeaters on 2M than any other frequency. don't think that repeater technology is something specific to hams -- it's not. police departments and the like use repeaters for the same reasons that hams do. in fact, this created a big problem on sept 11, 2001 as several of the NYPD and FDNY repeaters were located atop the WTC.

the disadvantage of repeaters is simple: in order for the repeater to work, you need power and the antenna has to be upright. these are not likely conditions in areas overcome by, for example, a category 4 or 5 hurricane. while tons of lead acid batteries may delay the inevitable, there is a finite amount of no-AC-power operation time for any repeater unless expensive measures have been taken (e.g. a diesel genset and good sized fuel tank, as you would find mounted behind a police station). nevertheless, hams are resourceful people and generally fixing the repeaters is an immediate priority in diaster areas. moreover, all the equipment necessary for a repeater can be carried in the back of a Tacoma, with room to spare. so if a makeshift antenna can be erected on the mountainside, a substitute repeater can be up and running in a few hours to replace the one crushed by the flying oak tree.

one way to look at a ham repeater is as an analog of a cell site. having many cell sites make it possible for your low power cellphone to communicate anywhere the global phone network reaches. similarly, hams link repeaters using point-to-point RF, the phone network, or these days using the internet. all of these methods allow greater "reach" from your low power HT. with the exception of point-to-point RF, the other methods require public infrastructure that may or may not be available when the SHTF.

speaking of the 'net, i've discussed above mainly voice communications. hwoever, hams also have packet radio technology at their disposal. so email and traffic nets can be set up without relying on the Internet -- instead of wire and fiber, RF is substituted. think of it as a wireless LAN, capable being accessed by anyone in an area of a few dozen miles in diameter.

in short, ham radio is not a singular thing; it is a wide, expansive hobby with many aspects to it -- you simply choose the parts that you enjoy. it's no different than with trucks, some like lifting and then offroading their Tacos and others make lowrider bling-bling trucks out of them. similarly, hams do HF, VHF, UHF, microwave, CW, packet, APRS, DXCC, contesting, SSTV, fox hunting, RACES/ARES(*), and so on and so forth.

ps:
useful/interesting sites:
http://www.qrz.com/i/howtoham.html <<<***
http://www.qrz.com/p/testing.pl <<< ***

http://wireless.fcc.gov/services/amateur/
http://wireless.fcc.gov/services/am...sing/index.html

http://www.arrl.org
http://www.qrz.com
http://www.eham.net
http://www.ew.usna.edu/~bruninga/aprs.html

(*) RACES/ARES
http://www.races.net/
http://www.races.net/links.html
http://www.ares.org/
Link Posted: 8/2/2006 7:12:11 AM EST

for mobile to mobile communications, such as would occur when off-roading, you can use "simplex" (direct) communcations in the VHF 2 meter band. no repeater needed, you are talking directly to each other. a common frequency for initiating this is 146.52MHz, the national simplex calling frequency. once you have contact made you can move up a few hundred kilohertz and use any of the designated simplex frequencies to carry on.

using an HT (handie-talkie) running 1 to 5W, you can expect up to about 10 miles of range. it depends highly on the terrain (flatter better) and what sort of antenna you have connected.

using a mobile rig running about 50W into a roof or bracket mounted antenna will net you anywhere from 10-50 miles of range. generally the curvature of the earth will cause problems, so it is better to be up on a hill of you are trying to reach out past 20 miles or so.

a 2M-only HT is about $130-150.
a 2M-only mobile is about $140-180.

many HT's and mobiles are "dual-band" in that they operate on both 2M (~146MHz) and 70cm (~440MHz). this gives more flexibility for operating. note however there are far far far more repeaters on 2M, so there is no significant downside to getting a 2M-only rig.

popular HTs and mobiles come from the Big Three: Icom, Yaesu, and Kenwood all make fine radios with marginal differences. mostly it's individual preference, unless one feature is striking you just right.

the Icom V8000 is a very nice 2M-only 75W mobile rig. i happen to own two of them. as for HT's, there are also many types; i own a Yaesu VX6R -- tri-band (incls 220MHz) super small and completely waterproof. i also own an Icom 24AT, a rugged dual-bander which i have had since 1991. it has never let me down and i've worked through a few Nor'Easters and hurricanes with it.

http://www.yaesu.com/
http://www.icomamerica.com/
http://www.kenwood.net/

one thing i just realized, i never really explained what modulation is. simply put modulation describes the technique used to put the audio input to the radio (i.e. your voice) onto the RF carrier. there are many ways to do this, each with advantages and disadvantages. moreover, not only can it be done in the analog domain, but it can be done digitally as well. i'll only discuss the former as there are very few consumer digital radios to be had.

the most common analog modes are CW (continuous wave), AM (amplitude modulation), FM (frequency modulation), and SSB (single sideband [suppressed carrier]) modulation.

CW is used for morse code and is very efficient for long range comms. CW is not really a modulation method per se, but nevertheless we treat it as such.

AM, as you may be aware, is used for broadcast radio stations (hence the "AM band" name) and for shortwave stations (like Voice of America and Radio Free Europe). because of the low fidelity of AM, and it's susceptability to interference, AM radio has been relegated mainly to talk and newscasts. note that CB uses AM as well.

FM, as you are also aware, is used for broadcast radio stations and also is the mainstay for VHF/UHF communications. above 50MHz (6M), 99% of ham, all of FRS/GMRS, marine, and all public service/safety use frequency modulation. FM provides far greater fidelity (accuracy of the receiving radio's output to the transmitting radio's input) than any other modulation type. therefore, FM is very useful for music transmission. and similarly, FM makes 2 way radio communications crystal clear. most folks who have only used a CB are incredulous at what a 2M ham rig sounds like. the difference is due to the use of FM -- and not power or anything else.

SSB is the most complicated of all of the noted modulation techniques. simply put, SSB is an adaptation of AM with a little math (a Hilbert transform) thrown in. the result is a VERY efficient way to transmit speech over long distances. SSB is the primary modulation method used by hams when operating below 50MHz (6M). there are actually two types of SSB (USB and LSB) and in order to communicate both parties need to use the same type. nevertheless, SSB is one reason you can talk a few thousand miles on a couple of watts.

Link Posted: 8/2/2006 7:12:58 AM EST
since someone is bound to ask... what does 2M mean? why is it seemingly used interchangably with 146MHz?

hams simultaneously use one of two terms to describe the band they are discussing: frequency or wavelength. the two are related by a constant known as C, the speed of light. it turns out that after you crunch the numbers, you can easily convert between the two terms using the following rule of thumb...

300/freq in MHz = wavelength in meters
or the same rule but turned around,
300/wavelength in meters = freq in MHz

hence:
300/146MHz ~= 2 meters

and now you see why 146MHz and 2M are used interchangably.

simlarly, some wavelength to frequency conversions for other popular HF and VHF/UHF ham bands...
40M --> 300/40 ~=7.5MHz
20M --> 300/20 ~= 15MHz
10M --> 300/10 ~= 30MHz
6M --> 300/6 ~= 50MHz
1.25M --> 300/1.25 ~= 220MHz
70cm --> 300/0.70 ~=440MHz

other cool/random radio-related links...

wiki stuff of interest:
http://en.wikipedia.org/wiki/Amateur_radio

http://en.wikipedia.org/wiki/High_frequency
http://en.wikipedia.org/wiki/20_meters

http://en.wikipedia.org/wiki/Very_high_frequency
http://en.wikipedia.org/wiki/2_meters

ham radio bandplan:
http://www.arrl.org/FandES/field/regulations/bandplan.html

Link Posted: 8/2/2006 7:15:10 AM EST



I think one major concept that just isn't clicking with me is how HF exists at 30Mhz and below, VHF/UHF exists at 50Mhz and above, yet CB radios work off of 27 MHz.


yes, CB exists within the "HF" frequency range (~1MHz to 30MHz), as does amateur radio. CB is allocated, as you already know, a band right near 27MHz (~26.965 to ~27.405), and the amateur 10meter band is just slightly higher at around 28.0 - 29.7 MHz. all things being equal, CB and ham would have approximately the same range since they are both affected the same way by the ionosphere. but clearly there is something else different, something that gives one an advantage over the other... keep reading...



This is difficult enough for me to explain, but I'm hoping you'll realize what I'm getting at. How does a CB work off of 27MHz, when an HF radio uses nearly the same frequency, but is able to communicate exponentially farther? Is this because radio frequency has really no correlation with power, and it just so happens that at 10M, a frequency has the ability to reach and skip off the ionosphere?


power is one aspect of range, an important one -- but not the only one. as i discussed in the third or fourth post in my "ham 101" thread, the way the audio is modulated onto the RF carrier is extremely influential on how easy or difficult it is to recover the audio at the other end. AM is one of the worst possible ways to transmit voice, and that's the type of modulation CB uses. AM, combined with only 4 watts output, is just not going to make it as far as a superior modulation method combined with more power. in contrast with AM, SSB is much much much (i can't emphasize this enough!) more efficient in terms of using the available power to greatest effect. ergo, SSB, combined with the higher power available on ham rigs, allows for far greater communication distance at very nearly the same frequency as CB. so as you can see, it's not just about power.

(i would also like to point out here that the receiver section on a typical ham radio is miles ahead of the receiver section on a typical CB radio. you need to cut some corners in order to make a CB that sells for $50. a ham rig, on the other hand, is at a price point that allows for better components (oscillators, filters etc) and additional circuitry (especially DSP [digital signal processing]). so if you look at the entire communications path from strictly a power perspective, there are two factors: how powerful the transmitter is and how sensitive the receiver is. hence, you can improve range by increasing transmitter power and/or increasing receiver sensitivity. if you do both, you get a lot more range. this is the case with the higher power output and excellent receivers on ham radios. and we haven't even plugged in the benefit of using SSB modulation yet! remember, IT'S NOT JUST ABOUT POWER. lots of hams use less than 10W to talk around the world. the art here is understanding propogation conditions, using the right modulation mode, driving a proper antenna, and having a good quiet (low noise floor) receiver.



I guess I just don't understand how such a low frequency would have that ability (10M), and a 2M wouldn't.


the ionosphere does not reflect frequencies above about 30MHz. above that, they just keep on going, off towards Mars. so, unless under very infrequent conditions, 2M (~146MHz) can not be used for long distance comms as it will not bounce back down to earth. (aside: there is a aspect of ham radio which consists of bouncing 2M signals off of the moon. this is called "EME", or "earth-moon-earth" communications. in this manner you can use 2M/144MHz to talk to the other side of the earth. warning: you need a lot of power and a big ass beam antenna to pull this off. moreover, the antenna must be able to track the moon as it crosses the sky, guided either by optical means or by using ephemeris data)



I think that, after reading your "101" post, a mobile 2M radio would best suit my needs. I noticed you have a mobile 2M in your truck. Do you use the 146.52MHz much like you would channel 19, to scan for others? Are there a lot of drivers and truckers that use this also?


you can use the "national simplex frequency", 146.52 sort of like CB channel 19. my 2M radio is set up to scan it in one of the memory banks. often i will hear someone call on it, and answer back. sometimes they are just trying a new radio out, other times they are from out of town and looking for popular local repeater frequencies, and other times it's just to say "hi" and so forth. generally you can "meet up" on .52 and then move off slightly to allow others to use the calling frequency. or you can simply chat on .52, allowing a little extra time between alternating transmissions -- then if someone wants in, they will interject with just their callsign. at that point you will "recognize them" by repeating their call back and saying "go ahead" (in effect, handing them the baton for the moment), and thus allowing them the opportunity to either join your conversation or to call for another station that they may have had a prearranged hook-up time for. this is actually all very simple and the first time you hear it happen live it will be very clear to you how to do it yourself in the future. the operating procedures in place on ham radio make it a much more enjoyable environment for everyone.



Now, as far as licenses go. I know I should just go ahead and get the tech license, but I want to understand this first. The tech license states that it is for communicating over 50MHz.


that is correct. pass the Technician class written test (no morse code test required) and will you have full operating privileges over 50MHz (6 meters). your FCC callsign will arrive in the mail in about a week, and you are a ham. borrow/buy a 2M radio, and you can chat with the nearby hams on 146.52 and of course use the local repeaters as well. for any new ham i would suggest listening to conversations (called "QSO's") on the repeaters for a bit to get the operating procedure down. again, it's VERY simple but you should listen first to see how it's done before jumping in with both feet.



Does this mean you don't need a license to operate an HF radio?


you absolutely need a license to operate HF, and the catch is that (currently) you need to pass a 5 words-per-minute morse code listening test (in addition to a written test) in order to get a license to operate HF. this morse code requirement is actually expected to go away shortly (perhaps within the next 4-6 months) as the ITU (International Telecommunications Union, sort of like a "global FCC") and many countries have already done away with it. the USA is one of the few to still have a morse code requirement for HF bands. this is a ideological and philosophical issue more than anything, it has nothing to do with technical issues. long before SSB and FM were used, CW (morse code) was the predominant mode and it was a requirement to know it. these days, not even US Coast Guard radio operators are trained on morse code. so the FCC is catching up a little bit, and i expect that there will be a morse code-less HF license class well before this year is out.



In your "101" post, you stated that 462/467MHz radios were general purpose (no license required) radios. I don't understand that part if it lies above the 50MHz mark.


oh, maybe you have a basic misunderstanding about something -- hams don't own ALL the spectrum above 50MHz!!! hams have been allocated tiny little chunks, that's all. other chunks are used for hundreds of other purposes, including police, EMS, fire, military, coast guard/marine, national park service, business band radios, taxis, aircraft, cellphones, NASA, and so on. even your garage door opener has it's own band, as does the 802.11 wireless router you probably have at home. things you don't even think about, like the little RFID tags used to prevent shoplifting, have their own bands.

along those lines, the FRS (family radio services) and GMRS (general mobile radio services) have bands allocated in the 462/467MHz range. these are "the new CB's" -- walkie talkies sold in pairs EVERYWHERE (walmart, sears, you name it) and seen at amusement parks, ballgames, and soccer fields, etc so kids can stay in touch with their parents, hunters in a group can talk to each other, and so on. power limited and with fixed antenna sizes, they are channelized like a CB to keep operation simple. "mom, i'll be on channel 2, mmm-kay?" is all it takes. FRS, no license required. GMRS, you just need to send the FCC a filled out form and $50(?) to get a 5 year "family license" or something like that.

due to power limitations, there is no such thing as an FRS mobile radio, so you are limited to the little walkie talkies and about 2 miles range (approx). no FRS repeaters either to help things. so an FRS radio is not a substitute for a ham radio in all cases. you can't get the same range simplex nor can you utilize repeaters for even more range. on the other hand, FRS radios are dirt cheap, and if you are in a caravan of cars they sure are handy to use to talk between them.

Link Posted: 8/2/2006 8:46:35 AM EST
[Last Edit: 8/2/2006 9:10:44 AM EST by scoutmaster]
ar-jedi
Good post:
I think your fingers must be an inch shorter after that Piece .

Well covered.
The only thing I  possibly  think of adding is.
On VHF with as you put it (With Just A Little Help) you can communicate 40 to 50 miles or further consistently.

The short distance label (definition of short distance) definition is different with everyone.

SM
Link Posted: 8/2/2006 9:13:15 AM EST
ar-jedi:
Excellent series of posts!!
Keep up the good work.

FN
Link Posted: 8/2/2006 10:53:21 AM EST
[Last Edit: 8/2/2006 12:55:26 PM EST by CaptSchofield]
ar-jedi--like wow, all I can say is --- yea what he said---

very excellent response.

Nolan1964-- It really much simpler than you would imagine, it is just very complicated to explain, in writing, because of the varibles. And of couse, here on Arfcom one must be very careful when trying to explain anything. ar-jedi did a exemplary job!
Link Posted: 8/2/2006 1:58:26 PM EST
First of all...AWESOME THREAD!  Thank you to all of you that are helping us learn!  I've got two pages of notes written down, and every website referenced bookmarked.  I see many hours ahead of learning, and I think aiming for getting a license is one of the things I'd like to aim for.

I'm prepared really well for most SHTF incidents I can think of, except for communications to "the outside world" (meaning outside my local area of course).  I would like to get something immediately, so I can receive information if something were to occur really soon.

While I'm learning this "new to me" technology, what would be a good handheld unit to get in meantime?  Thinking of SHTF scenarios that can affect my area (tornado, earthquake, etc), I've tried to find a handheld that would give me the following features:

1.  Ability to transmit (or more preferably, hear) a decent distance (50 miles preferred, but at least 10 miles from somebody else.

2.  Somewhat weather resistant to rain/water/humidity

3.  Can take AA or AAA batteries, since electrical charging may not be possible

4.  Price under $250

On the recommendations on this thread so far, I tried to research the Yaesu FT-60R and VX-150.  They both fit under the price, but I can't tell if either are capable of the first three features I listed.  Am I in the right ball park on models, or should I be looking for something else?

Also, to boost range, do any of these models allow for removal of their attached antenna, and allow for connection to an external, larger antenna through a cable?  And, a question I haven't seen before here:  How long do the batteries on handhelds last, when left in a standby mode?  I'd like to be able to hear what others are saying, as this would be a great resource for news.  Not sure if we are talking 2 hours per charge, or 20 or more.

I'm very slowly learning here, and plan to educate myself much more in-depth.  I would just like to get something now in case something happens in the meantime, and I can look at upgrading later once I learn more about the abilities/features of different radios as I become better educated.

By the way, I'm in Indiana...mostly cornfields, some woods, and a lot of subdivisions located in my part of the state.

Thanks for your help!
Link Posted: 8/2/2006 2:34:32 PM EST
If you read into ar-jedi's posts, which in MHO are right on, you will come to understand the flat lands in general offer the best range for VHF/UHF. (aside from open ocean, mountain top to mountain top or to low earth orbiting satellites) Most of which few of us can lay claim upon.
If you're in the mountains of VA or CO then you have a limited area of VHF radio operation.
What works for one individual WILL NOT work for all & this, my friends, is where the knowledge of radio propagation comes into play...figureing out just WHAT will work for you under the given circumstances of YOUR location & YOUR needs.
Is it  simple??...NO
Can it be done?...YES
There are way too many variables to say that one size fits all...be it a particular radio or antenna ... or their combination ... back to understanding propagation.
Can it be learned?? ...Of course!
It just takes a little time & commitment on the part of the "student" to read & understand what's being presented. Then apply it to YOUR situation.
Read what the ham ops like scott, frank, ar-jedi & others are saying then coin your questions based on what they offer.
It's real easy for the newcomer to get totally overwhelmed with info & just say to heck with it. FULL STOP.. Ask if ya don't understand.. quote as necessary.. We'll help ya get thru it.
Best to all

FN
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