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robotastic / trunk-recorder

Records calls from a Trunked Radio System (P25 & SmartNet)
GNU General Public License v3.0
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Empty wav files, OS X, Airspy #73

Closed ddb closed 7 years ago

ddb commented 7 years ago

I'm using trunk-recorder on OS X Sierra. I'm using it with an Airspy. I'm using it to listen to the King County (WA) Pubilc Safety trunking system, which is a Motorola SmartNet system.

I am successfully decoding the control channel, I can see calls starting and stopping.

It is also creating wav and json files in the expected place, but none of the WAV files actually contain anything (I once -- ONCE -- got a WAV file that had a transmission in it).

I am unsure what to do except to start exploring the code and adding debug stuff to it.

Any ideas what to look at first?

dreinhold commented 7 years ago

It's probably the channel number to frequency lookup area. I see this system is re banded. I know I have have to edit it before for part of my system. I am moble now but the code is in smartnet_parser.cc

ddb commented 7 years ago

Hmmm. I suppose that should become an option when configuring a SmartNet system.

Thanks for the pointer!

ddb commented 7 years ago

Would it be as simple as changing smartnet_parser.cc:25 from:

freq = float(cmd * 0.025 + 851.0125 - 10.9875);

to:

freq = float(cmd * 0.0125 + 851.0125 - 10.9875); ?

I guess I'll just have to find out.

ddb commented 7 years ago

This was absolutely the issue. TYVM.

robotastic commented 7 years ago

Awesome! Thanks @dreinhold I keep meaning to put together a Wiki article on all of this. SmartNet doesn't always follow a standard channel plan and needs tweaking.