Not receiving VC/audio

[krokus]

I am receiving the CC from a nearby zone controller on MPSCS, and I have downloaded the DSD file of TG, but I see no decode of any audio.

I must have missed something, with PEBCAK being a real thing.

I tried to tune in the local NOAA station as a test, but that seems like a larger hassle than figuring out what I really want to listen to.

 

[krokus]

Doing a bit more digging, it appears I might have insufficient signal level, despite having green indicators, and a decent I/Q plot.

 

[btt]

Doing a bit more digging, it appears I might have insufficient signal level, despite having green indicators, and a decent I/Q plot.

Can you post a screen capture of the signal insights tab while monitoring the MPSCS system? Are you seeing BLKS/SEC > 0?

 

[radio3353]

...Are you seeing BLKS/SEC > 0?

What does '0' in this field indicate? I am getting that on one of the systems I have programmed. Thanks.

 

[btt]

Ideally you will see 54 BLKS per second from a control channel. Depending on the type of system, there are either 27 or 40 of those blocks that contain crc-validated block-messages that contain network information like WACN, SYS_ID, RFSS, SITE_ID, etc. These also contain information about the frequencies, channel spacing, phase1/phase2, and voice grants. If you see 0 BLKS per second, you aren't receiving anything including frame-sync words. This almost certainly means that the control channel is not active, the frequency is wrong, etc. If you are using the roaming/scanning feature, then you will see 0 reported sometimes as it switches from one channel to another. This is normal.

 

[btt]

Doing a bit more digging, it appears I might have insufficient signal level, despite having green indicators, and a decent I/Q plot.

If you see a green indicator and have a good I/Q plot, you should be seeing a good number of BLKS/SEC. If you can post some screen captures or email me directly, I'll help you get this figured out. I'm thinking that it may be something with the talk groups? Do you have "allow unknown talk groups" enabled?

 

[krokus]

If you see a green indicator and have a good I/Q plot, you should be seeing a good number of BLKS/SEC. If you can post some screen captures or email me directly, I'll help you get this figured out. I'm thinking that it may be something with the talk groups? Do you have "allow unknown talk groups" enabled?

I have not been able to play with it tonight, but the I/Q plot was not as tight as I saw in some of your videos, and the signal strength indicator was in the yellow. I will get to it tomorrow.

 

[krokus]

Finally had time to get back to the radio. The blks/sec range from 11 to 54, mostly in the 40s. The signal strength seems a bit worse than last week, but it it is a different time of day, etc.

I am going to try a UHF TV antenna I have sitting around, to see if that is better.

 

[krokus]

Finally had time to get back to the radio. The blks/sec range from 11 to 54, mostly in the 40s. The signal strength seems a bit worse than last week, but it it is a different time of day, etc.

I am going to try a UHF TV antenna I have sitting around, to see if that is better.

Yeah... That was a failure. The TV antenna was worse than the small mag mount whip that came with the radio. (The TV antenna was a cheap indoor flat panel, propped up in a window facing kinda towards the site desired.) Below are two screen grabs, the whip gave better signal, with less sync. (If the titles show, 2 is the whip and 3 is the flat panel TV antenna.)

I will try the external TV antenna tomorrow. If/when that doesn't work, then I will fab a mount for one of the 800 MHz Yagi I have, and go that way with things.

 

[btt]

54 blks /sec at -114 dBm is not bad. You are still not seeing any voice grants? (Nothing in the talk group log?)

 

[krokus]

54 blks /sec at -114 dBm is not bad. You are still not seeing any voice grants? (Nothing in the talk group log?)

No voice frames detected, and nothing that I can see in the logs. The signal levels vary, significantly. (See the attached pic)

I might take this with road trip, where I will be a bit closer to the site, and see what happens.

I hooked up to my external TV antenna, and got this on the same site. (I picked one of the better signal times.)

 

[btt]

You should definitely be seeing some voice grants. I think I may know what is happening now. I will have something for you to try soon.

 

[btt]

Please give the "alt testing" 2021-03-24_1550 version a try. Do you see any voice grants?

 

[goldmyne99]

This may or may not be related. Looks similar. Attached the console log with voice grant failures. I have driven to -60 dbm rf sig with same traffic ch timeouts. The log shows TDMA assigments. As far as I know, this is a Phase 1 system per the RR database. Not a main system for me, but this discussion prompted me to revisit.

 

[btt]

This may or may not be related. Looks similar. Attached the console log with voice grant failures. I have driven to -60 dbm rf sig with same traffic ch timeouts. The log shows TDMA assigments. As far as I know, this is a Phase 1 system per the RR database. Not a main system for me, but this discussion prompted me to revisit.

This appears to be something else. You are receiving good voice grants for 58905. Looks like a valid group on the WISCOM system. Not sure why you aren't getting the voice. The control channel appears to be transmitting a TDMA voice grant.

 

[goldmyne99]

It is strange, SDRtrunk software also has issues decoding this system for me. RF sig of -60 dbm makes no difference in my testing. It is about a 30 min drive from me. I was surprised to see the TDMA voice grants lost at -60.

 

[btt]

It is strange, SDRtrunk software also has issues decoding this system for me. RF sig of -60 dbm makes no difference in my testing. It is about a 30 min drive from me. I was surprised to see the TDMA voice grants lost at -60.

It appears you are getting the grants fine. When the receiver switches to the voice channel, it isn't finding a signal. I doubt the signal level has anything to do with it. Do you receive any phase 1 traffic on the WISCOM system?

-edit: How does your "estimated reference frequency" compare with the programmed reference frequency? Is the reference frequency still programmed with the value printed on the label?

 

[goldmyne99]

No audio on the p25rx. I have monitored the system for over 30 mins in the past when driving to the site with nothing heard. Logs always show TDMA assigns and timeout.

 

[goldmyne99]

-edit: How does your "estimated reference frequency" compare with the programmed reference frequency? Is the reference frequency still programmed with the value printed on the label?

Yes, same as label you printed.

 

[btt]

No audio on the p25rx. I have monitored the system for over 30 mins in the past when driving to the site with nothing heard. Logs always show TDMA assigns and timeout.

You may want to try the "alt testing" version. I found that there is one type of voice grant case that was not being handled. Hopefully 2021-03-24_1550 takes care of it.