I am monitoring a local control channel and it seems like I am missing audio from some group calls such as the one highlighted below. I can hear some traffic but it seems like I am only hearing half of the conversations. What am I missing?
I'm trying to listen to the public safety channels (EMS fire etc) in Jackson County Kansas. From what I understand it is a small county with only one control channel.
Is this the tower you are trying to listen too? It is the only tower that even has a 854.5875 channel but is not showing as control channel. You would need 3 dongles for this system.
Is this the tower you are trying to listen too? It is the only tower that even has a 854.5875 channel but is not showing as control channel. You would need 3 dongles for this system.
You'll need two dongles. You need to cover the 3.675 mhz spread between 854.0875 and 857.7125 with a little bit of room on each side. Each dongle, at 2.4 msps, would provide about 1.92 mhz with good performance. 1.92 * 2 = 3.84 mhz. So two dongles should do it.
Or, if you were inclined and felt it was affordable, a single Airspy mini at 6 msps ( about 4.8 mhz of peak performance) would cover that system as well. Airspys aren't cheap compared to dongles.
Thank you both for the information and also for breaking it down barney style. Now i understand that I need two dongles. Ill be on the hunt to see if I can run two SDR's on some sort of USB splitter since my computer only has one USB port.
I would suggest getting a powered port. Some of the 3 or 4 port unpowered have issues with sdr's because the laptop doesn't provide enough power thru the usb port, and then you start getting transfer buffer errors on SDRTrunk.