nd5y
Member
User radios transmit their radio ID on the input frequencies. They have to or trunked systems wouldn't work.
Police Encrypted Radio detector
- Thread starter balcone13
- Start date
As as been already said, you would need to monitor the repeater input. Also, this sounds rather similar to the Beartracker system.
wiki.radioreference.com
73’
BearTracker - The RadioReference Wiki
73’
A Texas trooper once told me they set up on an elevated section of the highway & wait on the "high rollers." He told me that the simplicity of VASCAR was rather easy to beat in court. Texas still uses VASCAR.
Police frequencies are intermixed or right next to other public service like fire, ambulance, etc, and business radios are also all around police frequencies. You would have to rapidly scan all the police specific frequencies to insure your not getting a hit from a bus or delivery truck or GMRS operator, etc. There is no way to use a broad band receiver and filter out just the cop stuff. And if you scan police specific frequencies you would have to scan thousands of them in a split second or risk not being informed there is nearby activity. Good luck with the project.
wtp
Member
monitor the input frequency, works for about 1 mile.
turn up the squelch, can bring the range down to a few hundred feet.
turn on attenuation, brings it down further.
take the antenna off, to really cut it down.
and if you do all the above at once....
they will be asking you what the radio is for !
turn up the squelch, can bring the range down to a few hundred feet.
turn on attenuation, brings it down further.
take the antenna off, to really cut it down.
and if you do all the above at once....
they will be asking you what the radio is for !
AB5ID
Member
You would only be monitoring input frequencies of the public safety system. Due to the RF sensitivity, you would likely only receive signals from less than half a mile away. If you could determine whether the P25 frames were encrypted, it might indicate that you picked up a police transmission in areas where only police communications are encrypted.
One potential issue is whether dispatchers also transmit on the input frequencies. If you were too close to a dispatch center, you might end up receiving their transmissions instead, which could be problematic. Do the dispatch centers transmit on the input frequency of the repeaters or are they linked by IP or some other network?
AB5ID
Member
Safety of course, safe driving and situational awareness are key! I didn’t mean to hijack the thread from the original poster. I think we’ve ventured into the realm of the theoretical at this point; not for any nefarious reasons, but just to explore the strange thoughts that pass through our radio brains.
wtp
Member
what i posted, i use.
and when my county went to 700 simulcast, i listened to the inputs as they are not affected by it.
and when my county went to 700 simulcast, i listened to the inputs as they are not affected by it.
AB5ID
Member
Does a radio hobbyist need FCC approval to use an SDR receiver?
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nd5y
Member
No but the receiver probably requires FCC Part 15 certification.
AB5ID
Member
Oh yes, because I'm sure all the RTL-SDRs, Airspys, and HackRFs have been meticulously checked for compliance. If not, I guess we're all just a bunch of rogue radio rebels, breaking the law one signal at a time.
The best way to defeat radar detectors is drive under the speed limit.
BinaryMode
Blondie Once Said To Call Her But Never Answerd
I shall open a thread to this. Thanks.
I have a solution for this now. I monitor an aircraft ADS-B API from the Internet using a script that will flash a Philips Hue light bulb red and send a Pushover notification to my phone.
Hiway Radar (Android Based) already does most of this.
Wow, I did not know this. You mean they issue tickets if you go above the speed limit? LOL.
Except in far west Texas. Speed limit was 70, I was going 75, every other freaking car was flying past me (easily 80+)...I was told if I'm not keeping up with the flow of traffic I'm a hazard.
BinaryMode
Blondie Once Said To Call Her But Never Answerd
Yep, I learned that in drivers Ed. The instructor told me you have to go with the flow of traffic. So then if you go to court I guess you have to demonstrate that to the judge. At least I would. On the other hand if you do want to stay at the posted speed limit and not go above like all the other morons then you'd probably wanna stay in the right lane where you're really suppose to. But the most accidents happen there (on coming merging traffic). My instructor told me to stay in the middle lane so you can go left or right if you need to.
Project25_MASTR
Millennial Graying OBT Guy
I mean...it's 75 on most Texas Interstates and many State Highways.
True, but this road was 70 and driving a company vehicle I can't risk a speeding ticket for 10 over the limit.
