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Build the antenna a little long and hang it. Find the frequency with the lowest SWR on your analyzer. In the app, open that antenna under Antennas → Trim from measurement and enter the reading; Feedpoint shows how much to cut from each leg (or from the end on an end-fed wire or a vertical), using L new = L × f measured / f target.

Save the measurement and the app learns this wire's real end effect K. From two or more cuts it also learns a fixed offset for the feed region, so the next cut lands closer. The free dipole calculator on this site does the first step.

The United States (Technician, General and Amateur Extra, plus Novice and Advanced for renewals), Canada (Basic, Basic + Morse, Basic with Honours, Advanced), the United Kingdom (Foundation, Intermediate, Full) and Germany (Klasse N, E and A). Each answer says allowed or not allowed with the clause behind it.

The rules are our own encoding of the regulation texts, and each set shows the date it was checked and links to its source. The current sets were checked between 29 October and 2 November 2026: 47 CFR Part 97 with the new 60 m rules of 13 February 2026, RBR-4 Issue 3 (July 2022), the Ofcom licence conditions with the 2024 power levels, and the Amateurfunkverordnung as amended in 2024 with class N. The IARU band plans for Regions 1, 2 and 3 show the agreed segments everywhere else; they are recommendations, not law. More countries follow in updates.

No. It is an aid for your own evaluation. In the US it follows OET-65 with ground reflection, the controlled and uncontrolled limits of §1.1310 and the §1.1307(b) exemption test. In Germany it follows the BNetzA method with the 26. BImSchV limits, in the UK the ICNIRP 2020 general public levels of the Ofcom licence condition, elsewhere ICNIRP 2020 or 1998.

Every saved record carries the date, the inputs, the rule edition and the sources, so you can show how you got the numbers. Go by the rules in force and measure when in doubt. Find it under Tools → RF exposure; the RF exposure calculator on this site runs the US method.

ADIF 3.1.8, the current version of the amateur data interchange format, as .adi files that log services and award programmes accept. Open the log and tap Field → Export and spot → Share ADIF. CSV is there too.

For park activations the file carries both the generic MY_SIG and MY_SIG_INFO fields and the program-specific MY_POTA_REF. An activation with several park references gets one file per park. Files are plain ASCII by default; to keep letters like é or ø, change Settings → Names and places in log files.

Settings → Back up shares one file through the share sheet: save it to Files, Drive or mail it to yourself. On the new phone, Settings → Restore a backup and pick the file. Feedpoint shows what is in the backup before it replaces anything, and you can undo right after. We have no server, so the backup file is the only copy outside your phone.

Open Settings → Restore purchases with the same Apple ID or Google account. On iPhone, Family Sharing works too. Pro is one payment; nothing renews.

The 7-day trial asks for no card and charges nothing. When it ends, every antenna, record and log you made stays yours to open, change and export.

No. Everything is worked out on the phone, so it works on a summit with no signal. There is no location permission: you type your grid square (4 to 10 characters) or pick a reference. The only network use is the store, when you buy Pro.

Every result shows its formula with your numbers and the source it comes from. If it still looks wrong, write to hello@mufatech.com with the inputs; a backup file helps. We answer every message and fix confirmed errors first. In the app, Settings → Send feedback opens a mail to the same address.