I'm setting up a RemoteHams server to remotely control my station including amplifier, antenna rotator, and switches and running into some latency issues with my Adalm-Pluto SDR setup using GNU Radio on a Raspberry PI. Audio delay is about 300ms which makes CW nearly impossible.

Current setup: RTL-SDR v3 for RX, separate TX path via relay switching. Internet connection is 100/20 Mbps fiber. Anyone have experience optimizing the audio buffer sizes in the RemoteHams configuration?

Also wondering if upgrading to HackRF One for full duplex operation would help reduce the switching delays I'm seeing.

I had similar latency issues with my F1ATB Remote-SDR setup initially. The key is that SDRs need 5.6MB/s raw but Remote SDR compresses this down to less than 100kB/s, so the bottleneck is usually in your audio processing chain. Try reducing your GNU Radio audio buffer to 128 samples and make sure you're using ALSA, not PulseAudio.

For CW work you really need sub-100ms latency. I switched from RemoteHams to a FlexRadio 6000 series - they were built from the ground up for remote operation with an open protocol. Audio latency dropped to about 50ms which makes CW workable. The initial investment is higher but the user experience is much better.

Check your network path first - run continuous ping tests to your remote site. I found my ISP was routing through an extra hop that added 80ms. Called them and got it fixed. With proper compression you should see about 100x reduction in bandwidth requirements so a 20Mbps uplink should be plenty. Also consider a dedicated Raspberry Pi running SimpleHRR - it's headless and optimized for low latency.