Is my T4 working or not?

[lakki]

Hello group.

I've started to monitor a local trunking system, but I'm not sure what I'm looking. The decode rate jumps up and down, mainly gets numbers when there's some activity on the channel. I'm getting lots of data, but it does not make sense to me (yet)

The database stays empty, although the system is very unused, as far as I know.

Any help appreciated

..
Erik

 

[richster]

Hi Erik,

Yup you are working! All you need to do here is get a better signal. I sometimes have problems running t4win in bad locations on my laptop, and t4win won't decode accurately even at 70% let alone 3%.

A couple of things I see in your screen shot thats rather strange. I see that T4Win is trying to decode a motorola signal, but the data in the window doesn't look anything like a usual motorola astro signal. I have found out recently that T4Win automatically assumes and decodes a motorola system until it can determine otherwise, and at 3% I don't think T4win can do that. If the system you are on is in fact a Motorola or Edacs system, then once you get a good signal you'll be off and rolling. But if it's a MPT-1327 system, T4Win will recognize and decode but you will get limited information. Rick is working on improving T4Win with MPT-1327 systems. I noticed you're in Findland, and this may also be a system that T4Win can't decode like TETRA. But it looks like it's trying.

Regards,
Richster.

 

[lakki]

The system is a Motorola system, I assume it's Type II.

I'm listening it with a VR-5000, the signal has a bit of noise so I have to improve the reception.

The database starts to fill automatically, when proper decoding occurs, or how?

..
Erik

 

[richster]

Yes everything is automatic. You will see talkgroups appear on the activity screen, and if you check the "talkgroup", and "radio id" areas, you will see which talkgroups and radios have been active. The only thing you might not see is affiliations. With the latest release of T4Win, I no longer get info in the "affiliations" area.

Regards,
Richster.

 

[SCPD]

The waveform above looks like APCO P25, not a Motorola 3600 baud. T4Win does not handle P25 signals. Otherwise, the signal looks clean, smooth, relatively noise-free.

-rick

 

[lakki]

The system is not a P25 system, it's definately a analog trunking system.
It was initiated in 1992, being one of the first virtually large trunking systems exported, supporting SpectraTAC, secure comms and multiple sites, I've been told when bumped into Motorola guys in DFW and told where I'm from

Spectra's, Systems Sabers and MTS2k terminals are used in the system, so it's definately not P25

I have to check the 'Recorder' output on the VR-5000, it is claimed to be a discriminator output but I've seen now conflicting comments. That might be a issue on decoding problems too.

..
Erik

 

[crayon]

lakki,

As a side point .. you might want to make sure that the cable that you plug into your soundcard is a NON-attenuating cable.

Also if your reception is faint, consider a high gain antenna like a yagi to boost your signal.

Good Luck!!