Initial TDMA CC support has been added to the P25RX starting with firmware version 2021-07-26_1219. It should support voice grants, but is untested. To test, enter the CC frequency, select "TDMA CC" on the power-up mode, and press the <write config> button. There should be lots of logging information in the console window (probably too much). Please report in this thread if you are able to test. Thanks!
TDMA Control Channel Support
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freqseeker
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This is from WSP P2 control channel. Is this what you're looking for?
Thank you sir, but no. Most control channels are actually phase 1 type and only phase 2 when they switch to a traffic/voice channel. A couple of people have recently discovered that there are some new TDMA full-time control channels. There are a few of us (OP25, DSD+) working on adding support for these new TDMA control channels (full-type phase 2). Nobody has captured voice yet. It is that new. There is a new version ready to go that hopefully will be able to capture some voice. It would be great if the P25RX captures it first!! : ). I believe that logging has been confirmed to work, but I haven't seen a log file yet.
freqseeker
Member
I didn't know that. I will try everything around me later this evening. Not sure I have anything that new. Thurston County has a new system coming up that may be what you're looking for but not sure about that.
Yes sir. It is a parsing thing that I didn't fix yet. I'll fix that now.
We are really close now. Unfortunately, where you see the $SYS_INFO line, the NAC got set back to 0x000 capture right before internalizing the scrambling matrix and switching to the traffic channel, so the voice audio in the mp3 was scrambled. That is fixed now in version 2021-07-27_2011. The next capture should be good. Post in this thread when you get it!
$P25_PII_CC: NET_STS_BCST (0x3b): lra=4, wacn_id 0x92715, sys_id=0x1f8, iden=8, ch=650 (freq=855.062500 MHz), srv_class=112, nac=0x039
BURST_0x0D:(0x39): 1c,79,39,39,83,f6,04,83,16,04,08,09,88,88,88,88,88,88,88,03,94,e2,b0,
$P25_PII_CC: SCCB (0x39): rfss=57, site_id=57, iden1=8, ch1=1014 (857.337500 MHz), srv_class1=4, iden2=8, ch2=790 (855.937500 MHz), srv_class2
rssi: -112 tsbk_ps 18 sa 1 ue 1 wacn_id 0x92715 sys_id 0x1f8 nac 0x039 rf_id 57 site_id 57 freq 855.062500 rfg 38 agc -65.7 $
BURST_0x0D:(0x00): 1c,40,04,82,8b,18,06,00,00,00,08,09,88,88,88,88,88,88,88,03,9c,86,d0,
P25_PII_CC: VOICE GRANT (0x05), iden=8, channel=651, freq=855.068750, grp=6150
$SYS_INFO wacn 0x92715 sys_id 0x1f8 nac 0x000
$TDMA VOICE GRANT_00, freq 855.062500, tgroup: 6150, slot: 1
grant (0x00) packet_idx 0, tgroup 6150 freq 855.0625 nac 57 rf_channel 651 follow: 0 (unknown tgroup) 6150 (unknown loc) 6150
control is switching to monitor grant for talkgroup on freq 855.062500
==============================================================================================
TDMA Phase II sync, freq: 855.062500, rssi: -111 dBm, TGroup: 6150, Desc: (unknown tgroup), rfg 38 agc -66.4 $
TDMA Phase II sync, freq: 855.062500, rssi: -112 dBm, TGroup: 6150, Desc: (unknown tgroup), rfg 38 agc -62.1 $** (voice)
TDMA Phase II sync, freq: 855.062500, rssi: -110 dBm, TGroup: 6150, Desc: (unknown tgroup), rfg 38 agc -64.6 $** (voice)
TDMA Phase II sync, freq: 855.062500, rssi: -116 dBm, TGroup: 6150, Desc: (unknown tgroup), rfg 38 agc -67.7 $
TDMA Phase II sync, freq: 855.062500, rssi: -115 dBm, TGroup: 6150, Desc: (unknown tgroup), rfg 38 agc -65.8 $
>== TDULC - Return To Control Channel Frequency 855.062500, rssi -115 ==<
rssi: -115 tsbk_ps 18 sa 1 ue 1 wacn_id 0x92715 sys_id 0x1f8 nac 0x039 rf_id 57 site_id 57 freq 855.062500 rfg 38 agc -65.8 $
rssi: -114 tsbk_ps 18 sa 1 ue 1 wacn_id 0x92715 sys_id 0x1f8 nac 0x039 rf_id 57 site_id 57 freq 855.062500 rfg 38 agc -66.7 $
rssi: -113 tsbk_ps 18 sa 1 ue 1 wacn_id 0x92715 sys_id 0x1f8 nac 0x039 rf_id 57 site_id 57 freq 855.062500 rfg 38 agc -67.4 $
rssi: -113 tsbk_ps 18 sa 1 ue 1 wacn_id 0x92715 sys_id 0x1f8 nac 0x039 rf_id 57 site_id 57 freq 855.062500 rfg 38 agc -70.2 $
You can read more about it in this thread. Up until now, P25 control channels have all been phase 1. (only the voice is phase 2/TDMA). Now there is a couple of systems popping up with TMDA / phase 2 control channels. The new firmware now supports this. I would like for the P25RX to be the first to capture some voice audio! Hopefully it will happen any time now. : ) You do have to switch to "TDMA CC" mode for the power-up mode on the P25RX Config tab.
P25 TDMA Control Channel decoding -- requesting help from experts
Hi Folks, It has been reported that some suspect portions of the new AEP P25 multi-state system (a Harris P25 system) being built out, specifically some sites in Texas at this point, are using the P25 TDMA control channel format. I am not aware of any publicly available software that can...
goldmyne99
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Would the Search DB For CC tab and Test Selected Frequencies help find a P25 PII CC?
You can read more about it in the thread linked below. Up until now, P25 control channels have all been phase 1. (only the voice is phase 2/TDMA). Now there are a couple of systems popping up with TMDA / phase 2 control channels. The new P25RX firmware supports this. I would like for the P25RX to be the first to capture some voice audio! (technically, it already did, but was scrambled due to NAC=0 setting. fixed in 07-27_2011 ver) Hopefully a good voice capture will happen any time now. : ) You do have to switch to "TDMA CC" mode for the power-up mode on the P25RX Config tab and then find a TDMA control channel. If you see lines in the console starting with P25_PII_CC, then you found one!
P25 TDMA Control Channel decoding -- requesting help from experts
Hi Folks, It has been reported that some suspect portions of the new AEP P25 multi-state system (a Harris P25 system) being built out, specifically some sites in Texas at this point, are using the P25 TDMA control channel format. I am not aware of any publicly available software that can...forums.radioreference.com
Thanks for that explanation. Unfortunately, I am unable to find any P25 control channels in my area that are phase 2, so I can't help with this.
Can we use the CC's that are found on the Search Tab or do we need to input a cc on the P25RX Config Tab to find a Phase 2 TDMA CC?
For those asking about finding TDMA control channels, please note that so far there are only a dozen or so found on two or three P25 systems built by Harris for utility companies (AEP, Duke Energy, etc.). These are the extremely rare exception to the rule, where 99.9% of P25 control channels are going to remain FDMA for a long time to come. Motorola hasn't even rolled TDMA control channels out yet for their ASTRO 25 systems, so if your local P25 system was built by Motorola (telltale sign being a WACN of BEE00), then you're not going to find anything in this regard.
Attached is the first TDMA CC based audio recorded with BTT receiver.i consider this to be good reception considering site is 30 miles away. Thanks Todd great job.
Bob
Bob
Congrats on the milestone! Was the voice channel on the same frequency as the control channel in this case?
Sounds great to me, considering I don't think any PII sounds good and considering you say it's from a site 30 mi away!
mike
Awesome! Thank you Bob!
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