I see Shadetree has done his research while I was posting.
Radio transmitters are not as anonymous as people think they are.
73
Jeff
Radio transmitters are not as anonymous as people think they are.
73
Jeff
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What would be the reaction if Hams used 11m legally using their calls.
- Thread starter KM3F
- Start date
My point is that the authentication doesn't use rise time. I don't intend on paying to read the first link, but the second link talks about adding intentional phase errors. Obviously, if a system is designed with fingerprinting methods in mind, great. But you are not identifying a transmitter on the rise time of the signal alone. And none of it pertains to CB radio.It's a good thing that they cited references.
Improved Radiometric Identification of Wireless Devices Using MIMO Transmission
Authenticating wireless devices based on features of their transmitted waveform has become a topic of considerable interest. Recent work in this arena has shown that examination of features in a modulated waveform can lead to highly precise identification of 802.11 devices. This paper...ieeexplore.ieee.org
Stay Connected, Leave no Trace: Enhancing Security and Privacy in WiFi via Obfuscating Radiometric Fingerprints: Proceedings of the ACM on Measurement and Analysis of Computing Systems: Vol 4, No 3
The intrinsic hardware imperfection of WiFi chipsets manifests itself in the transmitted signal, leading to a unique radiometric fingerprint. This fingerprint can be used as an additional means of authentication to enhance security. In fact, recent works ...dl.acm.org
It depends. Are those hams going to be running type accepted cb radios on 11m? Or whatever ham rig they happen to have?
If hams want to get on 11m with a type accepted radio that is clean not run big power, and trybto show others what can be done, awesome!!
If they want to show up on 11m with a kenwood, running 20+ watts, and lecture me about power, and audio, personally I'll tell them to step off, and then change the channel when they continue. I don't need that kind of shit in my life. I have been finding more and more that I vacate 38lsb for 39-55... mostly I just sit and sandbag. I don't have much to say most days...
If hams want to get on 11m with a type accepted radio that is clean not run big power, and trybto show others what can be done, awesome!!
If they want to show up on 11m with a kenwood, running 20+ watts, and lecture me about power, and audio, personally I'll tell them to step off, and then change the channel when they continue. I don't need that kind of shit in my life. I have been finding more and more that I vacate 38lsb for 39-55... mostly I just sit and sandbag. I don't have much to say most days...
It is absolutely NOT BS ! The information in post number 24 is correct. All radio transmitters do indeed have a telltale signature based not only on 'rise' time, but also on the frequency offset, AC ripple within the transmission, and a number of other detectable parameters.
Now that said, the chances that the FCC or any other countries radio authority is actually tracking people on 11 meters using this technology is very slim. However, if they really want to they can !
They can also DF any station really really fast if they need to. Here in Canada there is a nationwide network of SDR's located on hilltops and mountains operated by ISEDC (Canada's FCC). They can access any one or many of those SDR's instantly from any one of their offices and DF (to within a few hundred feet) a station within minutes.
If they really want to shut you down they sure can..........
Polish FCC technicians told me, that 3 seconds of signal is enough to get fingerprint of transmitter, to trace signal source it's minutes.
They have remote monitoring stations in many places to triangulate signal source. Nice R&S antennas BTW.
"Critical" freq's are monitored 24/7 by them.
Mike
They have remote monitoring stations in many places to triangulate signal source. Nice R&S antennas BTW.
"Critical" freq's are monitored 24/7 by them.
Mike
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As far as enforcement goes here in the US it is apparent that the FCC has very low interest in Ham radio and CB enforcement.
Not that they do no enforcement at all but it's my experience that to get there attention you need to be a total train wreck on the air.
There are many documented cases were ham have complained for months even years before enforcement happens.
Same for CB.
73
Jeff
Not that they do no enforcement at all but it's my experience that to get there attention you need to be a total train wreck on the air.
There are many documented cases were ham have complained for months even years before enforcement happens.
Same for CB.
73
Jeff
I should add that here in Canada the whole process is complaint based. If there's no complaints about your radio operations then there's no problem.
Once somebody complains about interference or whatever it sets the gears in motion for them to come pay a visit to your station............though just like in the U.S. it can take a LOT of complaining before they'll take action.
Once somebody complains about interference or whatever it sets the gears in motion for them to come pay a visit to your station............though just like in the U.S. it can take a LOT of complaining before they'll take action.
I am not disputing that there are characteristics that make a transmitter unique, I am merely stating that rise time, the subject of post 24, is not one of them. I also noted in my post above that it is more likely that they would use spurious emissions as a fingerprint, and what Mike just said supports exactly that. At S3 (-109dBm), most of the spurious emissions that are supposed to be at least 60dB down start to climb out of the noise when the carrier reaches S3.
I also don't dispute that a given radio will have its oscillations upon key down reach a steady state at different times compared to other radios, but even if this is what was meant by "rise time", it still don't work because there is no indication of when the transmission actually began for the timer to start. What happens if the oscillations reach half the max amplitude before they are strong enough for the receiver to detect them? That rise time calculation just got cut in half. Transmitters are undoubtedly unique, but rise time alone is useless and shouldn't have been used to describe fingerprinting
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Ok, I am wrong, but I still don't like their wording. If it were based on the rate of change at a particular instant during the rising period, like the slope of the rise at 75% of whatever the steady state value ends up being, I could see that being a thing. The way it is written suggests its measuring time, not slope, so thats what threw me off. But after thinking about it for a while, it makes sense now.
Sorry I blew up.
Sorry I blew up.
When I had interest in being a ham, there was a club in Las Vegas that held a class at the Air Force Base. Nellis Radio Amateur Club (https://nellisrac.org/). It was a several weeks long and went through the Tech handbook one chapter at a time and explained every aspect of the chapter being studied. Not sure if they're doing that any more.
I don't see any clubs doing that, but the opposite in what are basically cram sessions to get you through the exam, which may be fine, I'm not judging.
I guess they still do have the classes
You searched for class - Nellis Radio Amateur Club
nellisrac.org
Well that raises a question in my "punkin' head".....
When they say "fingerprint"............
are they saying...."this radio is a 1979 Cobra 148 from Taiwan"?????
or are they saying.... "this is the same radio that was transmitting 2 days 3 hours and 42 seconds ago on this frequency"????
It is easier to believe that they could match the "dynamic appearance of the signal" across multiple transmissions.... than to believe that they can tell you the "make, model and serial number" of the radio you are using.
When they say "fingerprint"............
are they saying...."this radio is a 1979 Cobra 148 from Taiwan"?????
or are they saying.... "this is the same radio that was transmitting 2 days 3 hours and 42 seconds ago on this frequency"????
It is easier to believe that they could match the "dynamic appearance of the signal" across multiple transmissions.... than to believe that they can tell you the "make, model and serial number" of the radio you are using.
This is the correct answer. Each radio has a unique 'fingerprint' based on a bunch of technical parameters including, but not limited to, rise time, AC ripple, frequency drift, freq. offset, bandwidth, harmonic content, and others.....
Radios made by the same manufacturer around the same date would certainly have had similar characteristics when new, but as they age, and especially as they are modded and given the golden screwdriver treatment, they acquire very unique 'fingerprints'.
It varies from club to club. One local club here holds sessions similar to what you described, with a couple months theory and regulations and even a CW course, even though it is no longer required. Other clubs are into it for financial gain only and offer cram sessions where you simply ;earn to memorize the correct answers to the questions and end up passing without a clue as how those answers were derived or why.
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