700 MHz P25 system not sending data?

[nd5y]

A few months ago they did something to the local 700 MHz P25 site. Unitrunker no longer recognizes it and won't display a system window. I tried logging it today and I just get an endless stream of this with time stamps and occasional errors. It looks like it isn't even sending normal control channel data any more.

  09 90 01 40 00 00 00 00 00 00 AC 82 op=09 unknown single Motorola OSP status=005 (5)
  09 90 01 40 00 00 00 00 00 00 AC 82 op=09 unknown single Motorola OSP status=005 (5)
 -89 90 01 40 00 00 00 00 00 00 48 B6 op=09 unknown single Motorola OSP status=005 (5)
  09 90 01 40 00 00 00 00 00 00 AC 82 op=09 unknown single Motorola OSP status=005 (5)
  09 90 01 40 00 00 00 00 00 00 AC 82 op=09 unknown single Motorola OSP status=005 (5)
 -89 90 01 40 00 00 00 00 00 00 48 B6 op=09 unknown single Motorola OSP status=005 (5)
  09 90 01 40 00 00 00 00 00 00 AC 82 op=09 unknown single Motorola OSP status=005 (5)
  09 90 01 40 00 00 00 00 00 00 AC 82 op=09 unknown single Motorola OSP status=005 (5)
 -89 90 01 40 00 00 00 00 00 00 48 B6 op=09 unknown single Motorola OSP status=005 (5)

 

[Jay911]

If all you're seeing is opcode 09, doesn't sound like a usable system to me either.

You should be seeing some opcode 3A/3B/3C (or BA/BB/BC) at the very least, I would think.

Care to zip up and toss a dump log to jay911@gmail.com?

 

[nd5y]

If all you're seeing is opcode 09, doesn't sound like a usable system to me either.

You should be seeing some opcode 3A/3B/3C (or BA/BB/BC) at the very least, I would think.

Care to zip up and toss a dump log to jay911@gmail.com?

What I posted is all that is in the log. The same 3 things over and over. The log file doesn't have anything else except for time stamps and a few errors because it is 30 miles away and not a strong signal at times. What does opcode 09 mean?

 

[mikey60]

It's a Motorola Specific OpCode (MFGID of 0x90, second octet), and we haven't been able to determine it's meaning definitively to date. Odd that it's the only thing being transmitted.

Mike

 

[Jay911]

Agreed.. first octet's '89' is '09' with hex 80 added.. I'm still trying to wrap my head around why bit 7 is sometimes 1 and sometimes 0 - to read the spec, it implies that without it, you're looking at a multi-packet TSBK, but that doesn't jive with the data I've been looking at.

In any case, the site is sending out virtually useless data, so it's not really operational.

 

[DaveNF2G]

Maybe they are using the signal for range testing.

 

[kd7kdc]

Maybe it is an encrypted control channel

 

[Jay911]

I would think if it was encrypted you'd still see some kind of hex data besides the 05-90 TSBKs.

 

[SCPD]

I'm still trying to wrap my head around why bit 7 is sometimes 1 and sometimes 0

TSBKs are sent in chunks. Motorola consistently sends out three at a time. That bit tells you which TSBK is the last. The decoder then looks for a new frame synchronization word.

In any case, the site is sending out virtually useless data, so it's not really operational.

Agreed.