Where can I take a free ham radio practice test?

Radio Horizon offers free Technician, General, and Extra class amateur radio practice tests at https://radiohorizon.tech/test.html with no signup.

What is a ham clock and grayline map?

A ham clock shows UTC time for logging QSOs. A grayline map draws the sunrise and sunset terminator, which often improves HF DX. Radio Horizon includes both on the homepage.

Can I look up a ham radio call sign?

Yes. Enter a US call sign on Radio Horizon to plot the FCC / Callook station location on the map.

Amateur radio ops console

See the grayline. Work the horizon.

Live UTC clocks, real-time ISS tracking, call-sign lookup, and a QSL card generator — plus free Technician, General, and Extra practice exams.

Local

--:--:--

—

Your station

Locating…

IP geolocation

UTC

--:--:--

—

Call sign lookup

FCC / Callook location for a station, plotted on the map.

Enter a call sign to plot the station.

Radio horizon

4/3-Earth line-of-sight range. VHF/UHF planning, not HF skip.

Tx 30 ft + Rx 30 ft ≈ 13.5 mi radio LOS.

ISS tracking

Loading ISS…

ISS frequencies

Downlink 145.800 MHz FM
Uplink 145.200 MHz FM
APRS 145.825 MHz FM
SSTV 145.800 MHz FM
UHF downlink 437.800 MHz FM

Confirm current ARISS / AMSAT assignments before transmitting.

Space weather

NOAA northern hemisphere aurora 30-minute forecast

NOAA SWPC aurora forecast

DX spots

Solar-terrestrial

Station log

Stored in this browser only. Export a CSV if you want a copy off-device.

See the grayline. Work the horizon.

Local

Your station

UTC

Call sign lookup

Radio horizon

ISS tracking

ISS frequencies

Space weather

DX spots

Solar-terrestrial

Station log

Recent entries