afu.tools

Amateur radio, hands-on

The toolbox for radio amateurs

afu.tools brings together what you really need at the radio, at the antenna and on the way to your licence: reference built on official data, calculators and apps that talk to your radio and your test gear.

Finds repeaters, bands, countries, local clubs and glossary terms.

Right now

New to amateur radio?

You can pass the exam in a few weeks with no prior knowledge. Four steps to your own callsign:

  1. UnderstandGetting started
How to get started

What's here

Six topics, the same as in the menu above. If the terms are new to you, each one is explained.

Getting started

From first interest to your own callsign: what the exam asks, where the next date is, how to study and which local club is near you.

Classes N, E and A are the three levels of the German licence exam. N is the entry level with low power on three bands, A allows everything. You can upgrade any time with a supplementary exam.

On air

On air: FT8 and JS8 with the radio on your USB port, control your own radio remotely, listen to networks, log in contests.

FT8 is a digital mode for weak signals. Each transmission lasts 15 seconds, and the computer decodes what your ears can no longer hear.

Maps

What's on the air around you: repeaters with line of sight, sites with webcams, live APRS stations, parks and summits for portable operating.

Repeater: an automatic station on a hill or tower that picks up your signal and sends it out again with more range. That gets a handheld over 100 km.

DX

Long-distance contacts: who's on the air right now, where your signal lands, which bands are open and when the satellite passes.

DX means a long-distance contact. Whether it works depends on the ionosphere, which changes with time of day, season and the sun.

Technical

Check antenna and radio before you go on air: measure the match, check harmonics against the limit, program memory channels, calculate.

SWR (standing wave ratio) tells you how well antenna and radio match. 1.0 would be perfect; from about 2.0 you lose noticeable power and the radio throttles back.

Knowledge

Official and club data, synced several times a day: who holds a callsign, which country a prefix belongs to, what's allowed on each band and what you may do abroad.

Band plan is how each band is split up by mode. It isn't law, but if you stick to it you won't bother anyone.

Apps

From our own workshop and from friendly projects. Some talk directly to the device on your computer.

Remote operating

Remote control

Your radio on any screen: listen, transmit and tune with a waterfall and all the controls, from the sofa, on holiday or from your phone. The small afu-remote program runs next to the radio, and you don't open anything on your router. With decoders for CW, FT8 and SSTV, a time machine, satellite operation and guest access for friends.

afu.tools/remote โ†’
Learn

Funkpate

Learning platform for the German licence exam with the official question pool: study plan, flashcards, mock exam. An AI coach explains the question instead of giving away the answer.

www.funkpate.de โ†’
Operating outdoors

xOTA map

POTA parks with the real reserve boundaries in seven countries, plus SOTA summits, BOTA bunkers, WWFF areas, castles and live spots. See before you set off where the area starts and where you may set up.

Open the xOTA map โ†’
Set up

Rigstudio

Read, edit and write back memory channels, menu and settings of Yaesu, Icom and Kenwood radios, with presets for contests, POTA or home. The radio is plugged into your computer and the browser talks to it via Web Serial.

afu.tools/rigstudio โ†’
Calculate

Antenna simulator

Model the antenna before the wire goes up the tree: enter the geometry, pick a frequency, get impedance, SWR curve and radiation pattern.

antennasim.afu.tools โ†’
Measuring over USB

Measure an antenna

Plug in a LiteVNA and let the browser measure: resonance, SWR, bandwidth and Q, plus a table of the bands the antenna is good for. For a magnetic loop, the whole tuning range.

afu.tools/vna โ†’
Measuring over USB

Measure harmonics

Is your radio transmitting clean? With a tinySA Ultra the browser measures the fundamental and harmonics and compares them with the limit in the Radio Regulations. It takes you through the measurement step by step.

afu.tools/oberwellen โ†’

How the site works

  • No account
  • No tracking
  • Sources disclosed
  • Works offline

Data you can trust

Callsigns from the Bundesnetzagentur (BNetzA, German regulator), repeaters and local clubs from the DARC, area boundaries from BfN and OpenStreetMap. Synced several times a day, every source named with licence and date.

Your data stays with you

No third-party servers for fonts or maps. For use on the go you can store the band plan, repeater list, glossary, exam dates and calculators on your device, around 1 MB, only when you press the button.

Open for your own projects

Everything the site knows is also available as JSON through the API, as RSS and ICS to subscribe to, and as guides to build your own.