SDRs

Trunk Recorder has been test with 2 different drivers, which support a range of SDRs. In general, it seems best to use multiple SDRs with a smaller bandwidth, instead of a single SDR that covers a wide swatch of spectrum. Using multiple SDRs means that you can assign a recorder to a subset of a systems spectrum range and do not have to have it process the entire range.

The following SDRs have been used and are known to work (add in any you have had success with):

Osmocom Driver

Any thing that is supported by GR-OsmoSDR should work with Trunk Recorder. Below are the ones that I have either personally tried or heard from folks that they got working.

• RTL SDR dongles: There are tons of different USB SDR dongles that are based on the RTL2832U chipset. They are essentially repurposed digital TV receivers, so they they aren't the perfect SDR... but they certainly work well enough. Pay the extra $10 and get one with a TXCO in it, which prevents the tuning from drifting around as the dongle gets warm. The dongle can cover up to about 2.5MHz. I like the RTL-SDR.com and NooElec Smart dongles. They are both about $20, is it is pretty affordable to get 4 or 5 dongles. You can plug a bunch of them into a USB hub and be able to cover multiple systems. Currently, this is my preferred option.

• HackRF One: The HackRF is a great SDR that can both transmit and receive. It can receive up to 20MHz of spectrum and you can tune it down to about 6MHz. Unfortunately, it costs about $300... thats a lot of dongles.

• BladeRF: BladeRF is another TX/RF SDR and it adds in a FPGA. Again it is able to receive a wide band of spectrum, 28MHz and also has a builtin FPGA. In theory the FPGA could be used to offload processing from the CPU.

• AirSpy: A RX only dongle that provides about 10MHz of coverage.

USRP/UHD Driver: I think Trunk Recorder should work with Ettus SDRs, but I have only tested it with the B200. These SDRs are the real deal, and pretty expensive. This is probably overkill for recording a trunk system.