Guide Network radios

Guide: network radios

What it is. A network radio is an SDR that sits on another computer (or is a network device) and sends its samples over your LAN. OnAir can use it as if it were plugged in. This is handy when the antenna is on a roof or in a shed with a Raspberry Pi, and you want to decode at your desk.

Adding one

1. In the source list at the top, open the drop-down and choose Add network radio....
2. In the Network radios window choose the Type, type the Address and the Port, and press Connect. OnAir probes the radio for a few seconds without freezing the interface; a failure shows "Cannot connect" with the reason.
3. The radio then appears in the radio list with the others. Remove (under "Added radios") deletes it.

Types and default ports:

Type	Default port	What you run on the far side
PlutoSDR (by IP)	0 (libiio's default)	Nothing: type the Pluto's IP (USB gadget 192.168.2.1, or its Ethernet address).
rtl_tcp	1234	rtl_tcp on the computer with the dongle. OnAir shows a hint if it is not listening.
SoapyRemote	55132	SoapySDRServer --bind. Fill Remote driver with the SoapySDR driver (mirisdr, or driver=sdrplay,serial=1); leave empty to list what the server offers.
SpyServer	5555	An Airspy SpyServer with a radio plugged in.
Hermes Lite 2	1024	The radio on the LAN.
Red Pitaya	1024	The radio on the LAN.
SDR++ server	5259	SDR++ started with sdrpp --server.
SDRplay nRSP-ST (SDRconnect)	5454	SDRconnect with its WebSocket server on, with the nRSP-ST selected.

For some types a search can fill the address from the answers on your network.

Notes per type

• rtl_tcp: 8-bit samples up to about 2.5 Msps. Only one program can use an rtl_tcp server at a time: close other clients.
• SoapyRemote: needs the SoapyRemote client module. If OnAir says it is missing, install it (Debian or Ubuntu: sudo apt install soapysdr-module-remote; macOS: brew install soapyremote) and restart OnAir. A build without SoapySDR shows "This build has no SoapySDR, which SoapyRemote needs."
• SpyServer: if it answers but no radio is plugged into it, plug one in and restart the SpyServer.
• SDR++ server: takes one client at a time; close SDR++'s own client first. The source's settings (gain mode, bias tee, AGC and so on) show up under Radio settings after connecting.
• nRSP-ST: OnAir connects to SDRconnect, not to the radio itself, because SDRplay's own transport is not public; what SDRplay documents is the SDRconnect WebSocket API. No password is needed or stored. AGC, bias-T and the notches are not in that API, so they are not offered. The implementation was written from the public specification and tested against a simulated SDRconnect; no real nRSP-ST was available, so tell us on GitHub what you see (check).
• KiwiSDR: supported since 0.2.7 as a network radio (Add network radio... > KiwiSDR, port 8073): the Kiwi's IQ mode, 12 kHz of spectrum around the tuned frequency, sent over a WebSocket. It suits narrowband HF modes only. Not yet tested on a real Kiwi. See KiwiSDR.

Sharing your own radio

In Data feeds there is Share the radio's samples as an rtl_tcp server: a second OnAir (Add network radio, rtl_tcp), SDR# or SDR++ can connect to your computer's address and the port. Samples are sent as 8-bit IQ at the rate the radio runs at. Let other computers connect (LAN) opens it beyond this computer; without Allow remote control (frequency and gain) clients cannot change the frequency or gain. The panel shows the clients and how many megabytes were sent or dropped.

Tips

• Use a wired network for bandwidth above a few Msps. Wi-Fi drops samples quickly.
• The status bar counts lost samples ("Network radio: n samples lost (underruns)"); see Troubleshooting.
• The address must look like host:port for rtl_tcp, for example 192.168.1.20:1234.
• Keep network radios inside your LAN or a VPN; none of these protocols is encrypted.

Related

Supported radios | Network radios | SoapySDR | Troubleshooting