2020-01-12, 04:38 PM
(2020-01-11, 02:21 PM)w7thmark Wrote: Regarding the dongle, I've read that a high quality splitter is important. Any advice on a good one? Will this one do?
For the dongle itself, I've seen people talk about the RTL-SDR and the NooEeec, both similarly priced? Which way to go?
For a splitter, I use a Glomex RA201. It's considerably lower cost than some of the other splitters out there, but seems to do a good job for me. The specs say that it has an integrated pre-amplifier to reduce losses. As with any active splitter, you need to be really careful to ensure that power is always applied to it when your ship's VHF is on. If it fails or loses power, there is a risk to your AIS receiver, as there is nothing to prevent the RF power from your ship's radio from going directly into your AIS receiver.
I have used a NooElec on the boat, and have that one on the bench right now. It's a good quality device, and I believe worth the little extra money over the little plastic dongles out there. One thing I did the other day was to check the frequency offset for it, just out of curiosity. Surprisingly, it was almost nil - the most I saw was 2PPM. This is much better than some of the really cheap SDR dongles you can buy.
At the moment on the boat I use a combined SeaTalk converter/GPS/AIS receiver from Quark-Elec. I like it because it has WiFi, USB, and NMEA0183 serial output. I put the USB into my OpenPlotter system. If for some reason my OpenPlotter system is down, I can use the WiFi connection directly from the Quark-Elec box to OpenCPN on my tablet as a backup. the NMEA0183 output is going to my new Clipper wind instrument (If I can ever get around to getting the darned thing installed!).