Unitrunker using one RTL dongle

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moonbounce

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I am using Unitrunker with one dongle to decode a digital AP25 digital and analog system. Every thing is working well except, does not have the best sensitivity it misses a lot of signals, also I always hear the digital noise, gain is set at 600, if I go to low I won't get any signal. The last problem is that I also get like a hissing sound, sometimes it is there other times it is not.
i just got this up and running today, any help would be appreciated.

MB
 

moonbounce

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I think I have it all figured out, VB Cable was too high, turned it down and now silence unless someone talks.

i don't have the sensitivity level as DSD 1.101 in signal reception but I am working on that one..
 

br0adband

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Get a second dongle, seriously. I know it can be rough sometimes - I only had one RTL stick for maybe 4 months before I finally realized having a second one would basically resolve all the issues I had or allowed me to do things better overall - but if you have intentions of monitoring trunked comms it's practically a must.

If you can only have the one RTL stick for whatever reason and you wish to monitor a P25 Phase I or Phase II system then perhaps you might consider looking into setting up OP25 which can do that with just one RTL stick and do it extremely well, actually, but it requires using Linux (Ubuntu 14.04, specifically, is the easiest Linux distribution to get it functional in minimal time)

Since Unitrunker really can't receive the control channel and decode it at the same time it might be able to provide the analog audio to listen to (or pass to DSD or DSD+ for decoding the digital side) your best solution will always be having two RTL sticks for it to work with if Unitrunker is all you wish to use.

It is definitely possible to get by with just one stick but you'll have exactly the problems you've noted, especially missed comms because it can't monitor the control channel simultaneously as the voice channels (whether they're analog or not). It can either tune and decode the CC or tune a voice channel (A/D) but not both at the same time - that's why having the second RTL stick is so relevant because that would allow Unitrunker to constantly monitor the CC on one receiver dedicated to that purpose while passing on the necessary tuning info it decodes from the CC activity to the second RTL stick which is designated for the voice channel duties whether analog or digital.
 

moonbounce

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Two dongles it is, I do have enough of them sitting around, I didn't realize that it would make such a big difference. I am just getting started with Unitrunker, it is a lot of fun now that I have learned how to use it.

Thanks
MB
 
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