Cherokee and Clay County SO Using Encryption

[Klentathu]

Dear Trumpetman:

First of all, there is no decoding, just demodulating. Clay County uses NexGen 96 inverted GFSK on both Sheriff and Fire/EMS frequencies, and Cherokee County was using TRBO inverted C4FM modulation but Cherokee Co had to switch back to analog because they forgot to get FCC approval for that emission type on their current frequency of 158.970. Cherokee County may still use digital on their TAC channel of 159.105 but they rarely use that frequency at all. None of these systems are encrypted, just NFM digital modulation. Macon County is still analog UHF, Graham County is still analog VHF, and I have no clue on the rest as they are out of range.

I have demodulated Clay County but I do not listen to them on a regular basis because I live in Cherokee County and too many frequencies at the same time means to many missed transmissions.

 

[SquareCircle]

Wow, way to keep it friendly and non-derogatory towards a fellow forum member there boss. I would also be interested in monitoring the same areas, but when a simple question garners a response like this I really have to rethink why myself (or anyone) would want to even ask questions.

Kind Regards,
SC

 

[Quantar22]

Can you kindly explain this "TRBO inverted C4FM modulation"? For those here who don't know what that is... I was under the impression that MotoTrbo was TDMA not FDMA which would rule out C4FM as that is a FDMA mode... I am guessing if you invert it then it turns into FDMA?

 

[trumpetman]

Whoa now, easy killer, it was just a simple question. I wasn't expecting a lesson on semantics, modulation schemes or how my question wasn't properly worded. You on the other hand....

Decoding and demodulating are one in the same in this context, it's NXDN not NexGen, and modulation schemes are irrelevant...I have a portable transceiver that does the hard work for me. Although I will admit TDMA & C4FM are about like comparing a Chevrolet to apples...

Now back to business.... Let me be more specific, can anyone provide the color code, timeslot, and group IDs for the MOTOTRBO channels in use in WNC. You can reply via PM if you want to keep the information secure.

 

[W8EMX]

Klentathu - Don't you think that was a bit harsh of a response to a simple query? I like to think of these forums as being a place to share ideas and information - not bash each other. Civility goes a long way.


DTS

 

[Klentathu]

First, let me apologize if my response appeared harsh. Unfortunately, I was my mother was an English teacher, and to this day she still corrects my English, and it sometimes rubs off on me. I certainly meant no disrespect to the forum members.

Regarding question #1 on C4FM transmission mode, No, I do not know the technical aspects but, if you go to Digital Speech Decoder (software package) - The RadioReference Wiki on this website, there is quite a good primer on the subject. I know the demodulation for what Cherokee County was using because I demodulated (decoded if you prefer) it using DSDWIN ver 1.60 and the settings were for inverted C4FM modulation. I got the best audio I have ever heard on any digital system I have heard, especially P-25.

Regarding question #2. Sorry, no, I do not know color codes, timeslots or group ID's for either Clay County or Cherokee County. I admit a little confusion because I sort of understand timeslot and color code to match the system if you own a DMR radio, and each unit may have an ID, but these are not trunked systems, just dual-simplex VHF repeater channels which can operate both analog and digital simultaneously, However, since I do not own a NXDN or DMR/MOTOTRBO transciever, I don't know the specifics of properly programming one to receive the desired non-encryped digital signal on a specific system.