SDR Frequency Guide
What's worth listening to, and where to find it: 50 signals for SDR and scanner users.
Need the licensed frequencies around you (police, fire, business, utilities)? Search the FCC licence data in the i-c.biz frequency database. Receiving is legal in most countries, but laws differ: in many places you may not share, record or act on what you hear, and decrypting encrypted transmissions is illegal.
Listen and decode with NyxScope
Every signal marked NyxScope can be decoded live, several at once, from one RTL-SDR. NyxScope is a free multi-protocol SDR scanner for Windows from ICBizLabs, the team behind kilaz.com, with a 30-day trial of its licensed features.
About this tool
Getting started
A cheap RTL-SDR dongle covers about 24 MHz to 1.7 GHz, which includes almost everything on this list. HF signals (time stations, CB) need an upconverter or an SDR with direct sampling.
Antennas matter
The stock telescopic antenna works for strong local signals. For aircraft, ships or satellites, a purpose-built antenna (see the Antenna Calculator) makes a much bigger difference than a pricier receiver.
Checked frequencies
Entries were checked in October 2026. NOAA's APT weather satellites were retired in 2025 and are kept on the list only as a reference.