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Unitrunker won't decode 800 Motorola Analog System

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garys

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I moved this from the Software Defined Radio forum per the suggestion of Unitrunker. Since I'm new to this, I didn't even know there was a trunking control channel decoding forum.


Well, this has me a bit baffled.

I have SDR# with trunking support running and feeding data to Unitrunker. Unitrunker will decode the various 93x.xxxx analog Motorola trunks in my area. Surprisingly, it even decodes the 77x.xxxx Motorola P25 trunk that the MA State Police is building. What it won't do is decode the MSP 800 Mhz analog trunk. Or rather it will when it feels like it, which isn't often. OTOH, Trunk88 decodes that same data like a champ. I get all sorts of data from that.

I'm running VBCable to feed everything. Everything being Trunk88, Unitrunker, DSDPlus, and DMRDecode. I think the problem is with my Unitrunker (1.27) set up, but I can't think of another parameter to change.

Anyone have any thoughts or suggestions?
 

SCPD

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There is also a voice decoding forum. You may want to check that out, too.

Unitrunker includes a diagnostic tool called UniScope that gives us a good picture of what's happening. Unfortunately, UniScope only works with audio input devices. Since you're running SDR#, we can use that to get a visual impression of the signal (and the general RF neighborhood).

In you can, please post a screenshot of SDR# with a "good" signal (good decode rate) and another screenshot of SDR# with a "bad" one (poor or no decoding).
 

garys

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I can do that. I think you want screen shots of the Uniscope with both good and bad (or no) decoding. I have looked at Uniscope and to my eye, the undecoded signal looks good. OTOH, the decoded signal on the P25 system looks bad. That's probably apples and oranges I know, but I found it odd. I can give you a screen shot of the non decoded 800 system and a decoded 900 system.

Speaking of which, when I'm moving from one control channel to another or one band to another, should I stop Unitrunker?


There is also a voice decoding forum. You may want to check that out, too.

Unitrunker includes a diagnostic tool called UniScope that gives us a good picture of what's happening. Unfortunately, UniScope only works with audio input devices. Since you're running SDR#, we can use that to get a visual impression of the signal (and the general RF neighborhood).

In you can, please post a screenshot of SDR# with a "good" signal (good decode rate) and another screenshot of SDR# with a "bad" one (poor or no decoding).
 

garys

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Here are two screen shots, both with what seems like reasonab
le signal, but no decode. Top is 800 and bottom is 900 Motorola. The screen shots really don't do the Uniscope justice. If you need something else or something better, let me know.


[/URL][/IMG]
 

SCPD

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Thanks gary. I was hoping to see two images of SDR#. Also, apologies for using the term "screenshot". An image of the application is what I meant.

If you can, try increasing the audio level from SDR# into VB Cable. The waveform is on the anemic side.
 

garys

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Thanks gary. I was hoping to see two images of SDR#. Also, apologies for using the term "screenshot". An image of the application is what I meant.

If you can, try increasing the audio level from SDR# into VB Cable. The waveform is on the anemic side.
I'm not sure what you want in terms of an image of the application. Do you want the main screen or the settings screen?

I'll try to increase the audio gain coming out of SDR#. I changed the sampling rate in VB Cable to 96,000, but that doesn't seem to help.

One thing that is odd is that when I first launch Unitrunker, most of the time it will track the 800 system. Then, if I stop Unitrunker and tune to a different control channel, it will not resume trunking the new control channel. Even more baffling is that usually it will track a P25 system that has poor reception on my dongle.

One thing that I know I have to work on when spring comes is replacing my antenna and cable. Often I can hear systems in my truck parked in my driveway that I can't in the house.

I might bring the set up to work, which is much closer to some of the transmitters and see if it works better.
 

SCPD

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I was hoping to see two images of the SDR# application window: one image with a good signal and one image with a bad signal where both images are taken on the 800 mhz control channel that is giving you trouble.
 

garys

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I was hoping to see two images of the SDR# application window: one image with a good signal and one image with a bad signal where both images are taken on the 800 mhz control channel that is giving you trouble.
Oh, that! :D I'll give it a try tomorrow. I know that they are different programs, but it also baffles me that Trunk88 will decode the same systems. Of course, Unitrunker is useful across a much broader range of system types, so I'm not complaining at all. If you ever get it to decode MotoTrbo trunking, I'll be ecstatic.
 

garys

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Update: Progress. I set the Sample rate on dongle to 1.92 MSPS and now get decoding on all three 800 Mhz control channels. 900 Mhz signal is done tonight, but I'll keep playing with the two different dongles I have and see what happens.

Top image is SDR# with Unitrunker decoding data.



Bottom image is SDR# with Unitrunker not decoding data.



I'm going to play with the audio output of SDR# to see if that helps.
 
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