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Posted: 4/13/2014 12:06:31 PM EDT
[#1]
One reason I've always been a fan of the older Nextel phones. You could switch them to a local mode that didn't require a signal.
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Posted: 4/13/2014 12:43:42 PM EDT
[#2]
Quote HistoryQuoted:
One reason I've always been a fan of the older Nextel phones. You could switch them to a local mode that didn't require a signal. How much distance you gonna get out of a milliwatt transmitter on a nextel? |
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Posted: 4/13/2014 1:23:12 PM EDT
[#3]
I would suspect the feds could shut off or jamb any type of wireless communication if they wanted to.
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Posted: 4/13/2014 1:44:22 PM EDT
[#4]
Quote HistoryQuoted:
I would suspect the feds could shut off or jamb any type of wireless communication if they wanted to. Use a 2m go box repeater, they jam it switch to 440. They jam that go to HF NVIS. |
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Posted: 4/13/2014 2:50:24 PM EDT
[#5]
radio free redoubt (y'all have to search yourselves, I'm mobile) had some stuff happening this weekend, Their "show" will air online tonight and be posted as a podcast right after....think he'll do an AAR of event (comms related)
Posted Via AR15.Com Mobile |
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Posted: 4/13/2014 3:11:22 PM EDT
[#6]
Quote HistoryQuoted:
Use a 2m go box repeater, they jam it switch to 440. They jam that go to HF NVIS. Quote HistoryQuoted:
Quoted:
I would suspect the feds could shut off or jamb any type of wireless communication if they wanted to. Use a 2m go box repeater, they jam it switch to 440. They jam that go to HF NVIS. Once you decide to throw away the rule books, just switch to the input frequencies of the law enforcement repeaters, use different PL tones and run simplex. |
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Posted: 4/13/2014 3:17:53 PM EDT
[#7]
Quote HistoryQuoted:
Once you decide to throw away the rule books, just switch to the input frequencies of the law enforcement repeaters, use different PL tones and run simplex. Quote HistoryQuoted:
Quoted:
Quoted:
I would suspect the feds could shut off or jamb any type of wireless communication if they wanted to. Use a 2m go box repeater, they jam it switch to 440. They jam that go to HF NVIS. Once you decide to throw away the rule books, just switch to the input frequencies of the law enforcement repeaters, use different PL tones and run simplex. I like the way you think. This is where data modes get interesting. A lot of info can be passed very fast. |
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Posted: 4/13/2014 3:27:02 PM EDT
[#8]
Quote HistoryQuoted:
Once you decide to throw away the rule books, just switch to the input frequencies of the law enforcement repeaters, use different PL tones and run simplex. Quote HistoryQuoted:
Quoted:
Quoted:
I would suspect the feds could shut off or jamb any type of wireless communication if they wanted to. Use a 2m go box repeater, they jam it switch to 440. They jam that go to HF NVIS. Once you decide to throw away the rule books, just switch to the input frequencies of the law enforcement repeaters, use different PL tones and run simplex. If you're throwing away the rule books couldn't the Ham guys jam the .gov guys' radios too? |
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Posted: 4/13/2014 3:42:41 PM EDT
[#9]
Quote HistoryQuoted:
If you're throwing away the rule books couldn't the Ham guys jam the .gov guys' radios too? In many cases, yes but it would not last too long unless a LOT of it happened at once and tied up their RDF units. |
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Posted: 4/13/2014 4:06:44 PM EDT
[#10]
Quote HistoryQuoted:
How much distance you gonna get out of a milliwatt transmitter on a nextel? Quote HistoryQuoted:
Quoted:
One reason I've always been a fan of the older Nextel phones. You could switch them to a local mode that didn't require a signal. How much distance you gonna get out of a milliwatt transmitter on a nextel? The same band and tech is used in the Motorola 900 MHz DTR radios. It's about a mile, two tops. They don't have removable antennas, but if they did, with parabolic grids, you could do a point-to-point link of about 30 miles. The other plus here is the radios are pretty jam resistant. Nextel uses a fixed table if I recall correctly, but the DTRs you can actually program the frequency set used for hopping, making jamming real difficult. (They'd have to kill the entire ISM band with enough energy to overcome the narrowband signal. I don't even think current .mil jammers can do this at an reasonable distance.) |
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Posted: 4/13/2014 4:08:55 PM EDT
[#11]
Quote HistoryQuoted:
Once you decide to throw away the rule books, just switch to the input frequencies of the law enforcement repeaters, use different PL tones and run simplex. Quote HistoryQuoted:
Quoted:
Quoted:
I would suspect the feds could shut off or jamb any type of wireless communication if they wanted to. Use a 2m go box repeater, they jam it switch to 440. They jam that go to HF NVIS. Once you decide to throw away the rule books, just switch to the input frequencies of the law enforcement repeaters, use different PL tones and run simplex. That's a great idea if they're operating near ham bands you have frequency-agile equipment on. A lot of fed activity is now on 800 MHz trunked systems, so it probably won't work for conventional 2M and 440 gear, even if it's frequency-agile. A while ago there were a handful of encrypted channels around 160 MHz but I don't think they see much use anymore. |
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Posted: 4/13/2014 4:16:49 PM EDT
[#12]
sub'd
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Posted: 4/13/2014 4:48:07 PM EDT
[#13]
I was listening to one of the IRLP repeaters near there. I could hear the cowboys were staging and getting ready to ride up over a hill and down to where the cows where. At least something was working. |
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Posted: 4/13/2014 6:06:21 PM EDT
[#14]
So the question is, will the FCC grant an Itinerate license if the needs statement says something like Coordination of militia field personnel. Almost worth the 250 bucks to see if the license would go through.
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Posted: 4/13/2014 6:18:54 PM EDT
[#15]
Quote HistoryQuoted:
So the question is, will the FCC grant an Itinerate license if the needs statement says something like Coordination of militia field personnel. Almost worth the 250 bucks to see if the license would go through. I'm thinking an FCC license is gonna be the least of your worries. |
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Posted: 4/13/2014 6:31:35 PM EDT
[#16]
Quote HistoryQuoted:
So the question is, will the FCC grant an Itinerate license if the needs statement says something like Coordination of militia field personnel. Almost worth the 250 bucks to see if the license would go through. "security services" "surveying operations" Don't think I've ever seen an Itinerant application not go through. They don't have to "jam" cell services, they just have the cell sites shut down for normal traffic. Their LE & gov traffic still goes through as does (I think) 911 calls. |
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Posted: 4/13/2014 6:43:52 PM EDT
[#17]
Quote HistoryQuoted:
How much distance you gonna get out of a milliwatt transmitter on a nextel? Quote HistoryQuoted:
Quoted:
One reason I've always been a fan of the older Nextel phones. You could switch them to a local mode that didn't require a signal. How much distance you gonna get out of a milliwatt transmitter on a nextel? I think those are 1 Watt on the direct mode, that's the limit on 900mhz. |
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Posted: 4/13/2014 7:23:54 PM EDT
[#18]
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Posted: 4/13/2014 8:11:51 PM EDT
[#19]
Quote HistoryQuoted:
here is some info that...ah well "my" place where i work we have this priority for say
tinfoil I had GETS/WPS in my last job. It puts you in the front of the line when the towers are overloaded. If the towers are shut down, you're still out of luck. |
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Posted: 4/13/2014 9:20:22 PM EDT
[#20]
Quote HistoryQuoted: That's a great idea if they're operating near ham bands you have frequency-agile equipment on. A lot of fed activity is now on 800 MHz trunked systems, so it probably won't work for conventional 2M and 440 gear, even if it's frequency-agile. A while ago there were a handful of encrypted channels around 160 MHz but I don't think they see much use anymore. Quote HistoryQuoted: Quoted: Quoted: Quoted: I would suspect the feds could shut off or jamb any type of wireless communication if they wanted to. Use a 2m go box repeater, they jam it switch to 440. They jam that go to HF NVIS. Once you decide to throw away the rule books, just switch to the input frequencies of the law enforcement repeaters, use different PL tones and run simplex. That's a great idea if they're operating near ham bands you have frequency-agile equipment on. A lot of fed activity is now on 800 MHz trunked systems, so it probably won't work for conventional 2M and 440 gear, even if it's frequency-agile. A while ago there were a handful of encrypted channels around 160 MHz but I don't think they see much use anymore. |
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Posted: 4/14/2014 6:05:35 AM EDT
[#21]
DC-to-Daylight rigs, with FLDigi, and rotate digital modes and frequencies. It'd be tough for anyone to track down the whole conversation. Just takes a lot of planning beforehand.
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Posted: 4/14/2014 6:07:27 AM EDT
[#22]
Quote HistoryQuoted: No, they are still on VHF not 800 Mhz. Only in the large east coast areas is 800 being used. Fed use P25/ AES encryption thats why you dont hear them except for the occasional guy you doesn't turn on his secure mode. |
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Posted: 4/14/2014 6:19:00 AM EDT
[#23]
Quote HistoryQuoted:
Ontario County, NY is switching to 700mhz. Already having tons of issues with coverage in our mostly-rural and really hilly county. Finger Lakes area was carved out by glaciers, not a lot of line-of-sight unless you're on top of the hills. Quote HistoryQuoted:
Quoted:
No, they are still on VHF not 800 Mhz. Only in the large east coast areas is 800 being used. Fed use P25/ AES encryption thats why you dont hear them except for the occasional guy you doesn't turn on his secure mode. I use a 700 MHz P25 handheld w/AES encryption at work. Hate the thing. The vocoder does a really bad job of filtering out background noise. Very often the listener at the other end states that I sound like I'm talking in a tin can or sound like a '90s era dial up modem. Give me back my VHF! |
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Posted: 4/14/2014 6:22:29 AM EDT
[#24]
Quote HistoryQuoted: I use a 700 MHz P25 handheld w/AES encryption at work. Hate the thing. The vocoder does a really bad job of filtering out background noise. Very often the listener at the other end states that I sound like I'm talking in a tin can or sound like a '90s era dial up modem. Give me back my VHF! Quote HistoryQuoted: Quoted: Ontario County, NY is switching to 700mhz. Already having tons of issues with coverage in our mostly-rural and really hilly county. Finger Lakes area was carved out by glaciers, not a lot of line-of-sight unless you're on top of the hills. I use a 700 MHz P25 handheld w/AES encryption at work. Hate the thing. The vocoder does a really bad job of filtering out background noise. Very often the listener at the other end states that I sound like I'm talking in a tin can or sound like a '90s era dial up modem. Give me back my VHF!  Only radio I use at work is an HT on 144.950, connected to a TNC, which digipeats thru the radio/tnc in my Jeep to get me out of the building. |
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Posted: 4/14/2014 6:39:46 AM EDT
[#25]
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Posted: 4/14/2014 12:23:08 PM EDT
[#26]
Obtain some UHF or 900 MHz trunking radios…then have fun. Nothing that says you can't trunk in the ham bands. Also, nothing that says you can't trunk on GMRS. Nothing that says you can't trunk between the two services if you're licensed…
If you're wanting to use government repeaters with different tones…it won't work unless you're talking trunked repeaters setup for multiple trunk groups. Playing on the inputs would, but you could also play on the outputs (playing on the outputs would drive the busy channel indicators insane and would effectively jam the repeater). |
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Posted: 4/14/2014 12:51:57 PM EDT
[#27]
Quote HistoryQuoted:
Obtain some UHF or 900 MHz trunking radios…then have fun. Nothing that says you can't trunk in the ham bands. Also, nothing that says you can't trunk on GMRS. Nothing that says you can't trunk between the two services if you're licensed… That would be a cool project, but I see the old timers stroking out over it. |
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Posted: 4/14/2014 3:28:33 PM EDT
[#28]
With the growth of mototrbo/DMR in the ham community, one could buy used Mototrbo radios and use them on the ham bands unencrypted. License an itinerate repeater pair, turn on the encryption and have a licensed portable repeater WITH 40 bit encryption for when stuff really happens.
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Posted: 4/14/2014 4:18:31 PM EDT
[#29]
Quote HistoryQuoted:
With the growth of mototrbo/DMR in the ham community, one could buy used Mototrbo radios and use them on the ham bands unencrypted. License an itinerate repeater pair, turn on the encryption and have a licensed portable repeater WITH 40 bit encryption for when stuff really happens. That still doesn't solve the jamming issue. So they can't do collections on you, oh well they will make it so you can't talk. [hypothetical] This is truly where digital stuff shines. A raspberry pi can be set up as a store and forward server on any freq or number of freqs with multiple radios. Data could be encrypted with gpg and sent to the server or between users using modes like PSK500r. Pictures could be the same thing. Honestly with a raspberry pi and the lcd display you could make a phone like device capable of "texting" encrypted messages. There are other things to consider but none of it matters because we can't play around with encryption. [/hypothetical] |
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Posted: 4/14/2014 5:06:21 PM EDT
[#30]
I'd like to see someone try to jam the ham bands... even if it is our crazy uncle. That'd be a nightmare. It's easier to hide in plain sight too.
Get some 12-10m handheld radios, and go for it. Obscure frequencies are your friend in that kind of case. When they start jamming, move frequencies. With the kind of propagation you get on 12-10m, you'd wind up with a lot of really angry people who'd want to come help. These guys I've heard are pretty useful in those situations. |
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Posted: 4/14/2014 5:07:43 PM EDT
[#31]
Quote HistoryQuoted:
That still doesn't solve the jamming issue. So they can't do collections on you, oh well they will make it so you can't talk. [hypothetical] This is truly where digital stuff shines. A raspberry pi can be set up as a store and forward server on any freq or number of freqs with multiple radios. Data could be encrypted with gpg and sent to the server or between users using modes like PSK500r. Pictures could be the same thing. Honestly with a raspberry pi and the lcd display you could make a phone like device capable of "texting" encrypted messages. There are other things to consider but none of it matters because we can't play around with encryption. [/hypothetical] Quote HistoryQuoted:
Quoted:
With the growth of mototrbo/DMR in the ham community, one could buy used Mototrbo radios and use them on the ham bands unencrypted. License an itinerate repeater pair, turn on the encryption and have a licensed portable repeater WITH 40 bit encryption for when stuff really happens. That still doesn't solve the jamming issue. So they can't do collections on you, oh well they will make it so you can't talk. [hypothetical] This is truly where digital stuff shines. A raspberry pi can be set up as a store and forward server on any freq or number of freqs with multiple radios. Data could be encrypted with gpg and sent to the server or between users using modes like PSK500r. Pictures could be the same thing. Honestly with a raspberry pi and the lcd display you could make a phone like device capable of "texting" encrypted messages. There are other things to consider but none of it matters because we can't play around with encryption. [/hypothetical] we need to sit down over beers someday
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Posted: 4/14/2014 6:49:53 PM EDT
[#32]
"trunking" implies a LOT of infrastructure, this is not practical within the confines of this discussion. Odd freqs are your friend.
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Posted: 4/14/2014 6:53:26 PM EDT
[#33]
Quote HistoryQuoted:
I'd like to see someone try to jam the ham bands... even if it is our crazy uncle. That'd be a nightmare. It's easier to hide in plain sight too. Get some 12-10m handheld radios, and go for it. Obscure frequencies are your friend in that kind of case. When they start jamming, move frequencies. With the kind of propagation you get on 12-10m, you'd wind up with a lot of really angry people who'd want to come help. These guys I've heard are pretty useful in those situations. Those guys have interesting gear, but a little pricey. |
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Posted: 4/14/2014 6:59:09 PM EDT
[#34]
Quote HistoryQuoted:
"trunking" implies a LOT of infrastructure, this is not practical within the confines of this discussion. Odd freqs are your friend. Darn, it's discontinued. It'd have been perfect! This radio was described on these pages a year ago by DanishM1Garand as "an HT for the Ham who wants to talk to no one."
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Posted: 4/14/2014 7:08:09 PM EDT
[#35]
I think digital would be the way to go for anything less than 100% tactical gotta happen now
communications. Also... a small tablet and a FT-817 running some lower power mode would be kind of amusing to find/jam. 2.5W on 17M running JT-whatever or even PSK-31 to someone running a semi-LOS relay 15 miles away on a hill, man, how'd you even find that to stop it? Now I've got to play with that miracle whip and the '817 to see is NVIS can happen with that lame of a setup... |
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Posted: 4/14/2014 7:35:33 PM EDT
[#36]
Quote HistoryQuoted:
I think digital would be the way to go for anything less than 100% tactical gotta happen now communications. Also... a small tablet and a FT-817 running some lower power mode would be kind of amusing to find/jam. 2.5W on 17M running JT-whatever or even PSK-31 to someone running a semi-LOS relay 15 miles away on a hill, man, how'd you even find that to stop it? Now I've got to play with that miracle whip and the '817 to see is NVIS can happen with that lame of a setup... JT65 and PSK31 are pretty slow modes the key is you want to be TX for the minimum amount of time possible I was playing around with this stuff a bit ago - this was a pretty big chunk of some posts: 
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Posted: 4/14/2014 7:53:49 PM EDT
[#37]
Quote HistoryQuoted:
If you're throwing away the rule books couldn't the Ham guys jam the .gov guys' radios too? Quote HistoryQuoted:
Quoted:
Quoted:
Quoted:
I would suspect the feds could shut off or jamb any type of wireless communication if they wanted to. Use a 2m go box repeater, they jam it switch to 440. They jam that go to HF NVIS. Once you decide to throw away the rule books, just switch to the input frequencies of the law enforcement repeaters, use different PL tones and run simplex. If you're throwing away the rule books couldn't the Ham guys jam the .gov guys' radios too? Ever hear of frequency hopping? |
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Posted: 4/14/2014 8:24:50 PM EDT
[#38]
Quote HistoryQuoted:
That still doesn't solve the jamming issue. So they can't do collections on you, oh well they will make it so you can't talk. [hypothetical] This is truly where digital stuff shines. A raspberry pi can be set up as a store and forward server on any freq or number of freqs with multiple radios. Data could be encrypted with gpg and sent to the server or between users using modes like PSK500r. Pictures could be the same thing. Honestly with a raspberry pi and the lcd display you could make a phone like device capable of "texting" encrypted messages. There are other things to consider but none of it matters because we can't play around with encryption. [/hypothetical] Quote HistoryQuoted:
Quoted:
With the growth of mototrbo/DMR in the ham community, one could buy used Mototrbo radios and use them on the ham bands unencrypted. License an itinerate repeater pair, turn on the encryption and have a licensed portable repeater WITH 40 bit encryption for when stuff really happens. That still doesn't solve the jamming issue. So they can't do collections on you, oh well they will make it so you can't talk. [hypothetical] This is truly where digital stuff shines. A raspberry pi can be set up as a store and forward server on any freq or number of freqs with multiple radios. Data could be encrypted with gpg and sent to the server or between users using modes like PSK500r. Pictures could be the same thing. Honestly with a raspberry pi and the lcd display you could make a phone like device capable of "texting" encrypted messages. There are other things to consider but none of it matters because we can't play around with encryption. [/hypothetical] hmmm... been looking for a project... |
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Posted: 4/14/2014 9:16:57 PM EDT
[#39]
Quote HistoryQuoted:
"trunking" implies a LOT of infrastructure, this is not practical within the confines of this discussion. Odd freqs are your friend. You can trunk on simplex. A trunk is a group of frequencies or repeaters that randomly selects the frequencies defined by the trunk group. Also known as frequency hopping. Add that on top of some of the "dual-band" trunking rigs Kenwood has made…you can literally randomly hop frequencies/repeaters on 25+ MHz of band width. Makes it extremely hard to jam everything. |
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Posted: 4/14/2014 9:19:05 PM EDT
[#40]
Quote HistoryQuoted:
hmmm... been looking for a project... Quote HistoryQuoted:
Quoted:
Quoted:
With the growth of mototrbo/DMR in the ham community, one could buy used Mototrbo radios and use them on the ham bands unencrypted. License an itinerate repeater pair, turn on the encryption and have a licensed portable repeater WITH 40 bit encryption for when stuff really happens. That still doesn't solve the jamming issue. So they can't do collections on you, oh well they will make it so you can't talk. [hypothetical] This is truly where digital stuff shines. A raspberry pi can be set up as a store and forward server on any freq or number of freqs with multiple radios. Data could be encrypted with gpg and sent to the server or between users using modes like PSK500r. Pictures could be the same thing. Honestly with a raspberry pi and the lcd display you could make a phone like device capable of "texting" encrypted messages. There are other things to consider but none of it matters because we can't play around with encryption. [/hypothetical] hmmm... been looking for a project... Why buy used? Connect Systems is making a MotoTRBO compatible HT for under $200. They have a TRBO/D*Star version in the works for the guys interested in digital comms. |
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Posted: 4/15/2014 4:55:09 AM EDT
[#41]
---------- Forwarded message ----------
From: <[email protected]> Date: Tuesday, April 8, 2014 Subject: [CS7000] CS7000 Final Hardware Design To: [email protected] After going back and forth between design concepts I have finally came to a decision. The decision was based on the outrageous policy of DVSI in relationship to licensing their technology verses buying their AMBE 3000 chip. First the decision and the reasoning. Because of available space, the only way I could get both DMR and D-STAR in the same CS700 chassis with the features I want is to have the Vocoder in firmware. So the first thing I did was contact DVSI and asked for a quote for licensing the vocoder to do both DMR and D-STAR which is a subset of the AMBE 3000 chip. The response I received from DVSI is as follows: =========================================================== The D-STAR and DMR software solutions are custom implementations designed to meet the specific requirements of a particular program. So they are not compatible/interoperable with one another and you would need to license two separate software libraries - one for DMR and one for D-STAR. The license costs for an off-the-shelf (e.g. TI C55x), object code implementation for DMR would include an up-front fee of US$145k, plus royalties starting at US$7.25. Please note that there is an option to extend the DMR-only license to a general LMR license that would allow use in DMR + dPMR + NXDN. There would be an additional up-front license fee of US$30k for the general LMR license and the royalties would start a bit higher at $7.75. The license costs for an off-the-shelf D-STAR implementation (object code) would involve an up-front license fee in the range of $165k-$170K, plus royalties of $7.75. Other terms and conditions contained in the standard DVSI software license agreement. And the AMBE-3000 chips utilize our latest AMBE+2 vocoder technology which offers some significant improvements (like noise suppression) over the earlier gen AMBE-20x0 chips, so the voice quality should be better with devices using the latest vocoder technology. ============================================================ So basically what they are saying is if I buy the AMBE 3000 chip it will cost be as low as $15 in quantities of 10,000 pieces over a six month period but if I license the firmware it will cost be $15.50 per radio and $345,000 up front. It does not take a mathematical genius to know which decision I should make. It is my opinion that the DVSI policy is in violation of the Sherman Anti Trust Laws in that their policy puts a significant disadvantage to the small company who cannot afford their outrageous upfront fees. Any lawyers out there have an opinion? With that decision out of the way I decided it is best to develop two separate radios. The first radio would be a D-STAR only radio selling for less the $200 and the second radio would be a D-STAR + DMR radio selling for about $249. The D-STAR only radio will have an optional WiFi module, space permitting, selling for about $40. If I do GPS it will be part of an optional Speaker Mike. Because of limited real estate inside the radio, it was decided to do the D-STAR modem using firmware instead of the MX589A. With the D-STAR only radio, I will consider having a version using CODEC2. This will cost about $15 to $20 less per radio because I do not need the AMBE 3000 chip. With this version I would not be surprised if some people figure how to get the AMBE 3000 firmware inside that hardware configuration and make a D-STAR compatible radio. However as a manufacturer I cannot support the pirated the software. My next task is to do the detailed design of the D-STAR radio hardware configuration. I expect to have that completed within a week. Jerry Wanger President Connect Systems Inc. I'll leave this here. |
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Posted: 4/16/2014 6:20:27 PM EDT
[#42]
Quote HistoryQuoted:
hmmm... been looking for a project... Quote HistoryQuoted:
Quoted:
Quoted:
With the growth of mototrbo/DMR in the ham community, one could buy used Mototrbo radios and use them on the ham bands unencrypted. License an itinerate repeater pair, turn on the encryption and have a licensed portable repeater WITH 40 bit encryption for when stuff really happens. That still doesn't solve the jamming issue. So they can't do collections on you, oh well they will make it so you can't talk. [hypothetical] This is truly where digital stuff shines. A raspberry pi can be set up as a store and forward server on any freq or number of freqs with multiple radios. Data could be encrypted with gpg and sent to the server or between users using modes like PSK500r. Pictures could be the same thing. Honestly with a raspberry pi and the lcd display you could make a phone like device capable of "texting" encrypted messages. There are other things to consider but none of it matters because we can't play around with encryption. [/hypothetical] hmmm... been looking for a project... Technically its not encrypted if you publicly post the key and its a known protocol... Just sayin... |
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Posted: 4/18/2014 11:06:36 PM EDT
[#43]
Here's a (possibly dumb) question out of left field.....
Does an HF radio that is transmitting have an on-air "fingerprint"? Kinda like a persons voice? Example: If twelve guys are working digital mode on HF, and one of them was mobile and got DF'ed but was gone when they got to the area.... Are there unique characteristics that would identify the radio of the one being looked for when it is heard later? Stated another way: Could a State level actor positively isolate and identify a particular transmitter just by it's transmission characteristics, and then recognize it when it is heard later? |
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Posted: 4/19/2014 1:45:10 AM EDT
[#44]
Quote HistoryQuoted: "trunking" implies a LOT of infrastructure, this is not practical within the confines of this discussion. Odd freqs are your friend. When I have the money I may try out the DMR/MOTOTRBO stuff. The huge linked areas and multiple time slots are kinda neat sounding. I guess you could think of that as a (locally)single-channel world-wide trunked system
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Posted: 4/19/2014 4:27:17 AM EDT
[#45]
our work radios are MOTOTRBO and they work pretty nicely - decent range on them for a marginal repeater location.
some of the typical digital issues are there (no fringe reception) but it's also nice most scanners don't scan for it. and that the radios can beat someone in a pinch 
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Posted: 4/19/2014 8:12:52 AM EDT
[#46]
The Connect systems radio is nice but the encryption is not compatible with Motorola. The radios will talk fine in the clear.
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Posted: 4/19/2014 8:15:02 AM EDT
[#47]
Big Full Page Ad in QST this mo for Connect Systems...advertising HT's for $180 I think
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Posted: 4/19/2014 10:53:02 AM EDT
[#48]
Quote HistoryQuoted:
Here's a (possibly dumb) question out of left field..... Does an HF radio that is transmitting have an on-air "fingerprint"? Kinda like a persons voice? Example: If twelve guys are working digital mode on HF, and one of them was mobile and got DF'ed but was gone when they got to the area.... Are there unique characteristics that would identify the radio of the one being looked for when it is heard later? Stated another way: Could a State level actor positively isolate and identify a particular transmitter just by it's transmission characteristics, and then recognize it when it is heard later? It depends on the radios. I know on VHF most radios have a distinguisable fingerprint, but they're running continuous carrier modes. If I recall correctly, the "fingerprint" is the start-up of the transmission, rise times, ringing etc on the waveform. I know there were a couple manufacturers that couldn't be fingerprinted and who they were was never discussed publically, but I think it was Alinco that never transmitted the same start-up waveform twice. On HF, you don't get the same startup sequence since it's not continuous carrier unless you're running AM. Add in atmospheric issues, and unless you're being heard via groundwave, I don't think its possible. They could ID you via other methods (software used, etc.) but that could be changed up pretty easily. It's worth noting also that virtually all the government RFQs I've seen spec DF equipment for 30 MHz and higher. Drones with DF, for example, can't DF a 40 meter signal. I'd be inclined to use SSB CB if possible, fairly hard to DF still, and no license violations for failure to ID, but a complete crapload of competing signals that would surely mess with any interception/DF activities. |
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Posted: 4/19/2014 11:51:43 AM EDT
[#49]
Quote HistoryQuoted:
It depends on the radios. I know on VHF most radios have a distinguisable fingerprint, but they're running continuous carrier modes. If I recall correctly, the "fingerprint" is the start-up of the transmission, rise times, ringing etc on the waveform. I know there were a couple manufacturers that couldn't be fingerprinted and who they were was never discussed publically, but I think it was Alinco that never transmitted the same start-up waveform twice. Quote HistoryQuoted:
Quoted:
Here's a (possibly dumb) question out of left field..... Does an HF radio that is transmitting have an on-air "fingerprint"? Kinda like a persons voice? Example: If twelve guys are working digital mode on HF, and one of them was mobile and got DF'ed but was gone when they got to the area.... Are there unique characteristics that would identify the radio of the one being looked for when it is heard later? Stated another way: Could a State level actor positively isolate and identify a particular transmitter just by it's transmission characteristics, and then recognize it when it is heard later? It depends on the radios. I know on VHF most radios have a distinguisable fingerprint, but they're running continuous carrier modes. If I recall correctly, the "fingerprint" is the start-up of the transmission, rise times, ringing etc on the waveform. I know there were a couple manufacturers that couldn't be fingerprinted and who they were was never discussed publically, but I think it was Alinco that never transmitted the same start-up waveform twice. I had to look at who was posting this. After I saw it was seek I might have to do some research or call a local guy that is into that kind of stuff. |
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Posted: 4/19/2014 12:43:10 PM EDT
[#50]
A few more details, my memory got jogged:
Here's one Ham paper on fingerprinting Scholarly paper using phase Fancier bayesian detection method In the early 90s the go-to fingerprint stuff for hams was Motron's TxID. It's mentioned in this RDF FAQ near the bottom. Nearly everything I've found is focused on start-up transients and assumes a full-power carrier signal, so using SSB with a delay before modulation to allow everything to lock up is going to help a lot. There's probably some frequency transients related to power loading that could be fingerprinted, but it's safe to say SSB (and SSB HF) is going to be a LOT harder to fingerprint than a 2M radio. The other solution if this were a big concern and it was just local comms would be to use something cheap and just dump the radios into ebay or into electronics recycling when done. The presumption here is you're operating legally, since otherwise they'd just arrest you and have the radio via that, so if the concern is being monitored after a legal protest, dumping the radios probably makes the most sense, along with other normal OPSEC stuff like never using a cell phone in the area. In this instance either the 900 MHz hoppers (which would be pretty secure, though since TriSquare seems to no longer making the XRS stuff, you're forced into the moto radios at $250 a pop) or CB might make the most sense. Maybe $50 AM CB man-packs with 7AH SLAs would work just as well. Really just depends on what the range and goals are. |
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