Radio fingerprinting software

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SCPD

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Does anyone know of a good source for transmitter fingerprinting software? We, our ham radio community, have an occasional jammer on one of our 2 meter repeaters and would like to identify the offender. I need something that will be able to record, and catalog, the transmissions. There was software out there years ago that worked on DOS, what I would like is software that will work on either Windows or Linux. RDF has been considered but it would better to positively ID the user for legal purposes. If anyone has a good source or a better way to fix our problem I welcome any input.
 

prcguy

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The software could never be used to positively ID a transmitter for legal purposes. The systems I've seen measure a transmitters key up characteristics which are somewhat unique but can also change slightly depending on frequency changes, etc.

You also need to have a radio available with raw discriminator audio out for the interface and you have to be able to monitor the offending radio on the repeater input. RDF takes some time and effort but has the best chance of catching a jammer, especially with the newer low cost RDF equipment.

While driving around with the RDF equipment (RDF box, receiver, antennas, laptop and GPS) you take several readings which will overlay a compass heading from your location in the direction of the transmitter of interest onto a Google earth map on the laptop. With just a few readings you can narrow down to a neighborhood then concentrate there.

The RDF I have was introduced at last years Dayton Hamvention and info can be found here:http://www.kn2c.us/
prcguy
 
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kb2vxa

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To begin with Win XP can emulate DOS among other things so all is not lost if you can dig up that old software someplace. Once upon a time there was a hardware board just for the purpose you have in mind but I have serious doubts of finding one like a certain repeater club used but I'll tell you the story of a lovely lady who was bring up three very lovely girls...

Oh, sorry, I got sidetracked by The Brady Bunch.

The swap net on the repeater was plagued by jammers so they started fingerprinting transmitters by consent, mine was logged just so nobody could accuse me of anything. As time went on they were identified by matching fingerprints of their legally identified transmissions elsewhere and the evidence submitted to the FCC which launched their own investigation. It wasn't long before the wolf tickets went out and the jammers disappeared.

Then there was another case I was involved with only this one used RDF which proved particularly difficult for a number of reasons. Evidence was gathered but never reached the FCC, that in itself busted the case wide open. Turns out the club president being in charge of it drew attention and all fingers pointed at him, like a politician caught with his pants down he resigned and was never heard from again.

I'm making two points here, equipment installed at the repeater site avoids all the headaches involved with RDF and proves more conclusive without ever leaving home. The other is evidence gathered by unauthorized persons will never hold up in court or with the FCC but gives probable cause for legally authorized investigation. The FCC like any other can't go on hearsay but given credible proof they have probable cause and will act on it.

One last comment, RDF in the hands of those who don't know how to use it leads to a wild goose chase or worse. Just to give you an idea, back in my CB daze I used a loop antenna, a map and a pencil to triangulate a jammer to a neighborhood that turned out to be a nest of antennas... which one? Smack in the middle was a tower above the rest so by laying the loop on its side elevation came into play. Sure enough it was the antenna head and shoulders above the rest.

Another time came the worst proving some CBers to be the dumbest four footed critters on the planet. While sitting on my friend's porch across the street I saw a car with the very same kind of loop I used pull up in front of my house and sit there. I walked over and asked what was going on, the driver explained they had tracked down the guy playing music and he turned up the volume so I could hear. He goes on to say it was "Stereo" which gave me a bit of a chuckle but played it cool, then I asked him if he had any idea who he was talking to. No was the answer I was looking for and then it came... I'm Stereo... WHAM! Knuckle sandwiches really don't taste good with blood for ketchup but they smell nice with a cloud of tire smoke.

The moral of the story is be it fingerprinting or RDF, if you don't know how to use it properly don't use it at all unless you have some sort of a death wish. (;->)
 

AZ_RADIO

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Northwest Arizona
Fingerprinting Software

Hello Frootydog,

There are several options and techniques to identify a specific transmitter, and to locate as well.

In direct response to your request, there is one program that was shareware which I have and would be glad to email you, however getting it up and running can be a challenge some. To properly identify a specific transmitter several things need to occur, #1) you need to have a database of "stored" radios, this is so that the identification system has a reference to check the offending signal against, #2) you need to be able to hear offending transmitter direct, in other words you need to be able to hear the offender on the input, #3) The signal being received needs to be above the noise, typically -90dbm is a usable signal strength.

A transmitter is identified by the very first few milliseconds of the transmission, this is where the individual transmitter key up and rise time, and transmitter stabilization occurs. The free software takes a sample of this area and preforms a crude identification of a signal based on audio from the discriminator of the monitoring radio, so it is not 100% accurate, and is not admissible in a court.

Motron Electronics makes a Transmitter Identification plug in board with software for a computer, this is a better solution.

In my opinion utilizing Direction Finding equipment is a much better way to locate the offender. There are many products on the market which can assist in the location of an offending transmitter. Doppler System , Winradio, Picodopp, and Ramsey which is the cheapest and it works ok.

I have several fixed DF sites as well a several mobile resources to locate offending transmitters.

Using Direction Finding equipment is not as simple as just installing the unit into the car and driving to the location of the offender. In order to be successful in locating an offending transmitter you must obtain a "fix" or location in which three or more readings from the df unit(s) have determined, Readings should be taken from several different locations which will provide a heading in degrees which determines the direction of the offending transmitter is located. This is it in a nut shell.

Depending on your budget you can spend as much as $40,000 for a very sophisticated DF unit. I have invested quite a bit of money on DF infrastructure and have used all of the units available on the market, only because I use this technology in my business.

I would suggest looking at the Picodopp product which is around $200.00 which is a very reliable and user friendly product, give Bob at picodopp a call and see what he can do for you.

I hope that this helps.

Respectfully,
AZ_RADIO
 

prcguy

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The reason I recommend RDF and Radio DF DDF2020T - GLOBAL TSCM GROUP, INC. is because it takes most of the guesswork out of the RDF process and even inexperienced users can get good results.

When its set up and you have followed the instructions including visiting Google maps for the suspected areas so they are in your laptops cache, You simply hit the keyboard space bar every time the offending transmitter is on air and that logs a compass radial on Google maps and they start intersecting and narrowing down the transmitter source very quickly.

The RDF main box also reads out compass headings in real time and the entire system is about $400 including the GPS receiver. You furnish a laptop and any kind of receiver to feed audio to the main RDF box.

The RDF box also has a speaker that has an antenna switching tone applied and you quickly learn the sound of signals with lots of multipath vs good solid signals with no reflections.
prcguy
 

SCPD

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The best way to get rid of a jammer is to act like they don't exist. Carry on like they're not out there. It can get really frustrating, but it's really the best way to handle it.

Don't give them the satisfaction of acnowledging on the air that there is a jammer out there. That only makes it worse. Make 'em think their radio isn't transmitting, they will go away.
 

pa3bnx

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Dec 11, 2013
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Hello Every Body,


Fingerprinting is not always a succes.

But using a doppler direction finder is more complicated but more usefull to nail down a transmitter.

Take a look at our sites for the SuperSimpleSoundDoppler
running on a PC with a soundcard.

We also did tests with correlation and plate antenna
and we experiment with automatic direction finding on HF


PA8W Radio Direction Finding

pseudo-doppler-radio-direction-finder

Cheap and working...
 

teufler

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ST PETERS, MISSOURI
XMIT_ID is the software I used when I was the OOC for the state of Missouri. Its DOS but once the program is running, you aren't hampered by not having windows. For the radio interference issue, it is a tool that you fan use when you can not get out on the road. Even if you can verify the "intruder" is back, by a radio fingerprint, you still will not know where the transmitter is at, so enter the Doppler ubit or fox hunting beams. If the intruder operates in the drive time hours, and if this is evening or night time hours, GOOD LUCK, as you will probably not see him, though the intruder will recognize you, you will scare the intruder. If your area has an active avid fox hunt group, you usually do not have on the air problems. Interference issues are inversal proportional to your local fox hunt group. Listen to the intruder. What backgroud noises do you hear. Any noises you hear can help narrow down the intruder.
 

DarkStarPDX

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Yeah, the FCC doesn't even bother with transmitter fingerprinting (when looking for unlicensed stations). Identifying a transmitting antenna via RDF techniques is the benchmark standard.
 

prcguy

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Depending on the city, the FCC just logs into a DOD DF system and the next time the problem transmitter keys up they have it pinpointed from many contributing DF sites. Or at least they did 20yrs ago.
prcguy

Yeah, the FCC doesn't even bother with transmitter fingerprinting (when looking for unlicensed stations). Identifying a transmitting antenna via RDF techniques is the benchmark standard.
 

DarkStarPDX

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Depending on the city, the FCC just logs into a DOD DF system and the next time the problem transmitter keys up they have it pinpointed from many contributing DF sites. Or at least they did 20yrs ago.
prcguy
Yeah, we just have one FCC guy here in Portland that drives around with a DF system on-board.
 

jdobbs2001

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You need a proper DDF system if you want to find the culprit. Typically the FCC will get a bead on the offender, have recordings of him speaking etc. There is no "Radio" fingerprint unless you are willing to spend about 80K for a Spectrum Analyzer that will do RF recording (of the spectra and the unique spectrum signature generated by the transmitter.)

But not even the FCC goes to that extreme.

Just work on getting enough DF info to provide to the FCC and they can do the rest.
 

techguru

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TEXAS
Would recording the IQ with a SDR be helpful since it basically records a chunk of spectrum?
 
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