Unitrunker not decoding VHF P25 control channel via Discriminator Tap

[mkewman]

I've tried clean installs both the latest beta and distributed versions and haven't gotten Unitrunker to decode the control channel via discriminator tap.

A normal MOTO IIi system decodes just fine, so i know the thing works, but I can't get this vhf system to decode.

 

[mtindor]

I've tried clean installs both the latest beta and distributed versions and haven't gotten Unitrunker to decode the control channel via discriminator tap.

A normal MOTO IIi system decodes just fine, so i know the thing works, but I can't get this vhf system to decode.

Might want to join the Unitrunker group over at Google Groups - https://groups.google.com/forum/?fromgroups#!forum/unitrunker

If your decoding a Type II system off of a tap, that in and of itself doesn't guarantee that the tap is working as it should. I can decode [at a reduced rate] a Type II system off of any scanner with a headphone jack with the audio piped into a line-in on a computer.

You'll want to use Uniscope to check what the signal looks like. If the tap is indeed a good tap, it could just be that the audio gain is too low or too high coming in from the tap to the computer.

Here's what Rick has to say about audio levels: Audio Recording Level Adjustment

Or it could simply be some strangeness in the particular VHF P25 system you are listening to. Rick has been making a lot of changes to UT Preview in order to get various VHF P25 systems to decode properly in UT It may be that the VHF P25 system you are listening to is one that requires dialog wth Rick to ensure that it's not a system<-->UT issue vs a tapped audio issue.

Mike

 

[mkewman]

I'm 99% sure it's the software. I can decode that 800 mhz rebanded type IIi system with "99% health"

i can't even get it to produce a log... but when i switch from a known 800 system to the VHF p25 system i get:

2012-08-01 13:25:55 			0 of 43 (0%)
BD86 I 111  unknown single OSW		*** with errors
7741 I 2C4  unknown single OSW		*** with errors
88E5 G 0E6  unknown single OSW		*** with errors
D852 I 17F  unknown single OSW		*** with errors
C873 G 3AE  unknown single OSW		*** with errors
A80E G 06D  unknown single OSW		*** with errors
8783 G 09A  unknown single OSW		*** with errors
D847 G 2FA  unknown single OSW		*** with errors
6260 G 02D  unknown single OSW		*** with errors
A488 I 3A7  unknown single OSW		*** with errors
B8E4 G 3C6  unknown single OSW		*** with errors
AB74 G 059  unknown single OSW		*** with errors
D052 I 103  unknown single OSW		*** with errors
ED7A G 3A7  unknown single OSW		*** with errors
C8F7 G 3AD  unknown single OSW		*** with errors
CFA8 G 06E  unknown single OSW		*** with errors
6AFD G 099  unknown single OSW		*** with errors
2012-08-01 13:25:56 			0 of 43 (0%)
4021 G 336  unknown single OSW		*** with errors
2455 I 2A2  unknown single OSW		*** with errors
61E8 I 029  unknown single OSW		*** with errors
B7A3 G 36D  unknown single OSW		*** with errors
B206 I 101  unknown single OSW		*** with errors
9741 I 2C7  unknown single OSW		*** with errors
88E5 G 0E1  unknown single OSW		*** with errors
D852 I 103  unknown single OSW		*** with errors
E802 G 06C  unknown single OSW		*** with errors
E25C G 376  unknown single OSW		*** with errors
25A5 I 2A2  unknown single OSW		*** with errors
61E5 I 285  unknown single OSW		*** with errors
E050 I 235  unknown single OSW		*** with errors
E2B6 I 209  unknown single OSW		*** with errors
D8A2 I 103  unknown single OSW		*** with errors
23B9 G 1F6  unknown single OSW		*** with errors
8DF7 G 396  unknown single OSW		*** with errors
345B I 071  unknown single OSW		*** with errors
5224 I 07E  unknown single OSW		*** with errors
B8E4 G 3C6  unknown single OSW		*** with errors
BB44 I 055  unknown single OSW		*** with errors
2012-08-01 13:25:57 			0 of 43 (0%)
D052 I 103  unknown single OSW		*** with errors
23B9 G 0F6  unknown single OSW		*** with errors
80E4 G 0F6  unknown single OSW		*** with errors
148D G 1A4  unknown single OSW		*** with errors
D852 I 103  unknown single OSW		*** with errors
7660 G 326  unknown single OSW		*** with errors
7769 I 2D4  unknown single OSW		*** with errors
8885 G 0E1  unknown single OSW		*** with errors
1668 G 2A0  unknown single OSW		*** with errors
4020 I 3C6  unknown single OSW		*** with errors
5378 G 08B  unknown single OSW		*** with errors
D052 I 103  unknown single OSW		*** with errors
7660 G 3A6  unknown single OSW		*** with errors
B8E4 G 3C6  unknown single OSW		*** with errors
CCBB G 2F0  unknown single OSW		*** with errors
1B4C G 00D  unknown single OSW		*** with errors
D817 G 2F1  unknown single OSW		*** with errors
B0E4 G 0C6  unknown single OSW		*** with errors
148D G 1A4  unknown single OSW		*** with errors
BB44 I 055  unknown single OSW		*** with errors
777C G 192  unknown single OSW		*** with errors
B65C I 3E9  unknown single OSW		*** with errors
2012-08-01 13:25:58 			0 of 43 (0%)
7660 G 3A6  unknown single OSW		*** with errors
94E9 I 2D4  unknown single OSW		*** with errors
8885 G 0E6  unknown single OSW		*** with errors
D852 I 103  unknown single OSW		*** with errors
7660 G 3A6  unknown single OSW		*** with errors
6AC3 I 0E5  unknown single OSW		*** with errors
AC74 G 399  unknown single OSW		*** with errors
D8A2 I 103  unknown single OSW		*** with errors
96E0 G 326  unknown single OSW		*** with errors
3C58 I 071  unknown single OSW		*** with errors
B0E4 G 0C6  unknown single OSW		*** with errors
148D G 3A0  unknown single OSW		*** with errors
674C I 382  unknown single OSW		*** with errors
B65C I 3E9  unknown single OSW		*** with errors
7660 G 3A6  unknown single OSW		*** with errors
B8E4 G 0C6  unknown single OSW		*** with errors
AB44 I 055  unknown single OSW		*** with errors
D052 I 103  unknown single OSW		*** with errors
9698 G 326  unknown single OSW		*** with errors
2012-08-01 13:25:59 			0 of 43 (0%)

 

[mkewman]

i suddenly just got it to decode for about 15 minutes, and it had about 50% health then i did something and it won't decode again.

in doing research i'm finding that most people have a capacitor in their tap setup. i don't... perhaps this is the issue?

 

[nd5y]

It works now!

Today I tried the latest beta and it now decodes the Paker County VHF P25 system.
The only problem is doesn't populate the peers tab.
It thinks the neighbor site control channels are alternates on whatever current site I'm decoding.

Peers worked properly on the old (current stable) version on 380 MHz systems.
I'll have to wait until the next good band opening so see if it broke on the beta version.

 

[SCPD]

Thanks Tom. We're getting there. For Mkewman, consider a resistor or potentiometer between scanner and computer. The capacitor is redundant. I use a 50k ohm pot on a BC895XLT. Without the pot, the signal clips even at the microphone input's lowest gain setting. Other scanners don't have such a strong output.

You can clip a Motorola or EDACS signal and decode. Not so with P25.

 

[mkewman]

I'll give it a try! Thanks Yuni!

 

[mkewman]

I've got it decoding at approximately 30% after putting a -40 db pad on it... so we're getting somewhere now...

 

[DaveH]

I've got it decoding at approximately 30% after putting a -40 db pad on it... so we're getting somewhere now...

I use an audio patch cord with inline volume control...not perfect but variable and gives
some level control.

Dave