Feedpoint: Antenna Calculator

Mufatech

In-app purchases

About this app

Feedpoint is a ham radio antenna calculator and station notebook that knows your call sign, country and license class. Measure an antenna and it tells you how much to trim. Type a frequency and it tells you whether your class may use it, with the rule. It works out your RF exposure distances and keeps the record. And it logs a park or summit outing without signal.

TRIM FROM MEASUREMENT
A formula gives a starting length; real wire never resonates exactly there. Each saved antenna keeps its cut log. Your analyzer reads 7.052 MHz and you want 7.100? Feedpoint shows the cut for each leg, here 2 5/8 in. From the first reading it learns this antenna's own end-effect factor, so the next cut lands closer. Dipole, inverted-V, EFHW, verticals, ground plane and J-pole are free. Pro adds 9 more kinds, magnetic loop and Moxon among them, and uses what one wire taught it to cut that wire for other bands.

CAN I TRANSMIT HERE?
Type a frequency, mode and power. Feedpoint answers yes or no for your class, one line per rule: segment, mode, power limit, band edge, and the clause it comes from. The IARU band plan for your region sits next to it. Rules for the United States (incl. the 60 m rules of February 2026), Canada, the UK, Germany and Japan, each with its source and date. Other countries are not in yet. Also: FT8, FT4 and QRP frequencies, and the NCDXF beacons on the air now. Pro checks as another class or country.

RF EXPOSURE, ON RECORD
The minimum distance to people for each band and antenna, the way your rules say: FCC OET-65 with ground reflection, controlled and uncontrolled, plus the exemption test; the BNetzA method for Germany; ICNIRP 2020 for the UK, below 10 MHz too; the MIC method for Japan; ICNIRP elsewhere. Every step is shown. The distances are free. Pro saves dated records per station and portable setup, as a PDF to sign and keep.

FIELD LOG WITHOUT SIGNAL
Big keys, a UTC clock, Return saves. Each call shows its DXCC entity from the bundled country file; dupes are flagged. Log fields for Parks on the Air® (POTA), SOTA and WWFF, with a counter that tells you when the activation is valid. Share ADIF 3.1.8 or CSV. A spot text for an SMS or APRS gateway, sent by you. A power budget for the battery. Logs are never limited. Pro writes one file per park and keeps several field kits.

ALSO IN FEEDPOINT
• Feedline: coax loss from the maker's datasheet, SWR, return loss. Pro: SWR at the radio vs at the antenna, stubs, toroids, baluns.
• World: grid square to position, beam heading short and long path, prefix to DXCC, sunrise and grey line at both ends. Pro: the grey-line map.
• Tools: dBm, S-units, ERP, Ohm's law, voltage drop, CTCSS, Q-codes, phonetics.
• Every result shows its formula, assumptions and source.
• Feet, inches and sixteenths, or metric. Five themes, Night red and Field for sun among them, all free.

FREE AND PRO
Free for good: your station, the band check for your class, six antenna kinds with trim, coax loss and SWR, RF exposure on screen, the field log with ADIF, every theme, backups. Pro is one payment. Try it free for 7 days; nothing renews, nothing is charged. When a trial ends, everything you saved stays yours to open, change and export. Modules added later come to Pro at no extra cost.

Try it on the sample station W1XFP first, then remove it in one tap.

In English, 日本語, Deutsch, Español, Italiano, Português, Français, Polski, 한국어, Türkçe, 繁體中文, Nederlands, Čeština, Русский and Svenska. No permissions. Nothing leaves your phone except a purchase through the store.

Calculations are aids; go by the rules in force and your own measurement. RF exposure results help with your own evaluation; they are not an official assessment.

Parks on the Air® is a registered mark of Parks on the Air, Inc. SOTA and WWFF are the names of separate award programs. Feedpoint is not affiliated with any of them.

No account. No subscription. Works without signal.

What’s new

First release.
• Trim from measurement: the cut for each leg from what your analyzer read
• Can I transmit here? Yes or no for your license class, with the clause
• RF exposure: minimum distance per band and antenna, FCC, German or ICNIRP rules
• Field log without signal, ADIF 3.1.8 and CSV, spot text, power budget
No account, works offline. A number looks wrong? Write to [e-mail]