RTL-Relay

RTL-Relay: Expose Your RTL-SDR to the Internet in One Command

If you’ve ever wanted to share your SDR reception with a friend across the country — or let multiple people tune the same dongle simultaneously — you know the drill: port forwarding, dynamic DNS, VPNs, firewall rules. It’s a hassle.

RTL-Relay fixes that. Think of it as ngrok for SDR.

What It Does

Point the rtl_relay client at your SDR dongle, and it instantly gives you a public rtl_tcp endpoint:

$ rtl_relay --device 0

=== SDR Available At ===
rtl-relay.com:20000
========================

That’s it. Share that address with anyone and they can tune in with SDR++, GQRX, SDR# — any standard rtl_tcp-compatible software. No port forwarding. No accounts. No VPNs.

Multi-User Relay

The first person to connect becomes the controller — they can tune frequencies, change gain, adjust sample rate. Everyone else who connects is a viewer — they receive the same I/Q stream and can demodulate independently.

This means a group of friends can listen to the same broadcast together, or you can leave a receiver running at a remote site and check in from anywhere.

How It Works

[Your SDR] ──USB──► [rtl_relay client]
                         ◄══WebSocket══► [rtl-relay.com]
                                              ──rtl_tcp──► [Listener's SDR software]

• A single Go binary runs on the machine with your SDR dongle
• It connects to the free public relay at rtl-relay.com over WebSocket
• The relay server allocates a TCP port and presents a standard rtl_tcp interface to the world
• Listeners connect using the same protocol they already know

Free and Open Source

RTL-Relay is fully open source under GPLv2.

The relay server at rtl-relay.com is a free community service — no accounts, no bandwidth caps, no strings attached.

Pre-built binaries are available for:

• Linux (amd64, arm64/Raspberry Pi)
• Windows (x64, with librtlsdr DLL included)

If you’d rather host your own relay server, the same binary runs in server mode on any VPS:

$ rtl_relay --server \
    --ws-addr :8080 \
    --ports 20000-21000 \
    --hostname your-domain.com

Bandwidth Reality Check

Raw I/Q streaming isn’t light.

At the default 2.048 MSPS, you’re looking at roughly 33 Mbps of continuous upload from the server to each listener.

At 1.024 MSPS (still plenty for WFM broadcast), it’s around 16 Mbps.

For narrowband work, 512 kSPS runs at roughly 8 Mbps.

Plan accordingly if you’re hosting your own.

Get Started

Website: https://rtl-relay.com

Source: https://github.com/SarahRoseLives/rtl_relay