P25 on the bands
-
- Super Member
- Posts: 257
- Joined: 23 Nov 2017, 20:14
- Call Sign: 26DG01
- Location: Democratic Peoples Republic of Devon
P25 on the bands
Is there any P25 activity on the bands? There are/were some P25 capable repeaters, but info seems to be scarce. What codec is the norm, VSELP, IMBE or AMBE? Is the ID system the same as DMR? What about network access codes? It seems 295 is common for repeater access in USA.
Sent from my GP300 using DTMF
-
- Radio Addict
- Posts: 655
- Joined: 16 Jun 2008, 11:52
- Location: Stroud, Gloucestershire
Re: P25 on the bands
Its really an American thing, I doubt there are many radios in the hands of amateurs over here.
Phase 1 radio systems operate in 12.5 kHz digital mode using FDMA access method. Phase 1 radios use Continuous 4 level FM (C4FM) modulation—a special type of 4FSK modulation
To improve spectrum use, P25 Phase 2 was developed for trunking systems using a 2-slot TDMA. Phase 2 uses the AMBE+2 voice codec to reduce the needed bitrate so that one voice channel will only require 6,000 bits per second.
Phase 1 radio systems operate in 12.5 kHz digital mode using FDMA access method. Phase 1 radios use Continuous 4 level FM (C4FM) modulation—a special type of 4FSK modulation
To improve spectrum use, P25 Phase 2 was developed for trunking systems using a 2-slot TDMA. Phase 2 uses the AMBE+2 voice codec to reduce the needed bitrate so that one voice channel will only require 6,000 bits per second.
-
- Super Member
- Posts: 257
- Joined: 23 Nov 2017, 20:14
- Call Sign: 26DG01
- Location: Democratic Peoples Republic of Devon
Re: P25 on the bands
That's fair enough, I knew it was largely a USA thing. I'm going to propose a UK P25-specific schedule for 70cm:
NAC: TX 293 (default), RX either 293 or F7E (all).
Talkgroup: 1 (default) , calling on FFFF (all)
Frequencies: Ideally the UK digital voice allocation for calling etc., but if it's busy with DMR go to 438.0375 and work up from there.
NAC: TX 293 (default), RX either 293 or F7E (all).
Talkgroup: 1 (default) , calling on FFFF (all)
Frequencies: Ideally the UK digital voice allocation for calling etc., but if it's busy with DMR go to 438.0375 and work up from there.
Sent from my GP300 using DTMF