Micro-FT8 · FT8/FT4 for QMX and QDX · Early pre-release

An FT8 station that keeps working when you put your phone away.

Micro-FT8 is a 35 gram station that sits next to your QMX or QDX and runs FT8 on its own: it decodes, calls CQ, works callers, and logs. Your phone is only a wireless remote. Use it to set up and check in, then pocket it. The station keeps going.

Getting started Downloads Set up a station, or get the firmware for the PoE-P4 and the Atom. Or watch the walkthrough.

PoE-P4 and AtomS3 Lite on a scale reading 34.9 grams, with a US quarter for size — PoE-P4 + AtomS3 Lite — the whole compute stack is **35 grams** (34.9 g on the scale). Quarter for scale.

Watch it work

A walkthrough of Micro-FT8 in use. It is hosted on YouTube, which loads its own player (privacy-enhanced mode) when this page does; open it on YouTube instead if you would rather not.

Why Micro-FT8

The station runs itself

Decoding, calling CQ, and the auto-sequencer all run on the station, not on the phone. Close the page, lock the screen, or switch apps, and it keeps calling CQ and working the stations that answer.

Nothing on the summit needs a network

The Atom runs its own Wi‑Fi, so you don’t need a router, cell signal, or app store. The map is served by the station, so it works offline. The clock syncs from your browser, so the GPS can stay home. The one network step is the first install: the app is downloaded once, through your phone, then lives on the Atom.

Join its network, open micro-ft8.local or 192.168.4.1: Getting started.

35 grams, about $29

The station is two stock M5Stack parts with no screen and no keyboard.

34.9 g on the scale. Real FT8 QSOs completed.

Your phone stays yours

The phone isn’t the station, so its battery, screen, and apps stay free for navigation, spotting, or a call home. If the phone dies, the station keeps operating.

Any browser works: phone, tablet, or laptop.

How it’s different

There are three common ways to run FT8 without a laptop. Each one makes a different trade-off.

	Phone app + radio	Radio with built-in FT8	Micro-FT8 + radio
Where FT8 runs	On the phone	Inside the radio	On a small station beside the radio
When the phone sleeps	Depends on the phone letting the app run in the background	No phone involved	Keeps operating; the phone is only a remote
Screen you operate on	The phone	The radio’s own screen	Any browser, or none once it’s running
Radios	Usually many	That radio only	QMX and QDX
What you add	A USB cable	A new radio	35 g, about $29

If you want the most radio choices, use a phone app. If you want nothing extra to carry, use a radio with built-in FT8. Micro-FT8 is for when you want your QMX or QDX to keep working while you do something else.

How it runs

M5Stack Unit PoE-P4 as the radio host, an AtomS3 Lite as the Wi‑Fi companion, no keyboard and no screen. All of the compute fits in 35 grams. Set up and check in from a phone, tablet, or laptop; no need to keep the page open. It has completed real FT8 QSOs on the air.

GPS is optional. Clock comes from the browser over the Atom link — open the page, sync once, operate. No GNSS module required for time.

P4 USB-host FT8 wasn’t a leap of faith: SteffenLav’s qmx-panadapter already ships FT8 on ESP32-P4 (M5Stack Tab5) with a live QMX. That work proved the silicon; Micro-FT8’s PoE-P4 build is the headless, browser-UI shape of the same idea.

Headless BOM (M5Stack)

The 35 g compute stack is two catalogue parts plus the Grove cable that ships with the PoE-P4. Radio and power are separate.

Part	Role	List
Unit PoE-P4 (SKU U213)	Radio host — USB to QMX, decode, CAT. Includes a 20 cm Grove cable.	$21.50
AtomS3 Lite	Wi‑Fi companion — serves the browser UI over the LAN.	$7.50
M5Stack compute BOM (list, excl. shipping)		~$29

Prices from shop.m5stack.com (USD, checked 2026-09-18). Does not include QMX/QDX, USB-C power bank/cables, or phone.

In the browser

Join the Atom’s own Wi‑Fi network directly (no router needed — a summit has no camp router any more than it has cell service), or put it on your home or camp network instead. Either way: no app-store install, just Safari or Chrome on a phone, tablet, or laptop. Three tabs: Operate drives the radio, QSOs is your log, Tools is everything around operating: who is hearing you (from PSKReporter, on the map or as a list), space weather, the map, and an SWR sweep for tuning an antenna.

The phone is optional once you’re set up. Open the page again at any time to see what the station worked while you were away.

Operate tab calling CQ at 4.8 W, SWR 1.04, with link status, queue, and a live decode — Operate — CQ out, power/SWR live, decodes still flowing.

Operate tab answering K8OCN with a report, the caller's decode flagged as addressed to me — A caller answers — flagged *→ ME*, queued, bearing & distance.

QSOs tab grouped by day with a QSO count, per-day ADI download, grid, distance and bearing per contact — QSOs — grouped by day, ADI per day or all.

Callsign card with grid, distance, QSOs in log, heard this session, POTA/SOTA status, and View on QRZ.com — Tap a callsign — grid, log history, spots, QRZ.com.

Tools tab with NOAA space weather: solar flux, A and K index, X-ray flux, solar wind — Tools — space weather, and the way into the map.

North America map with great-circle paths to worked grids, POTA and SOTA spots, and the grayline — Map — QSO paths, POTA/SOTA spots, grayline.

SWR sweep page after a run across 40, 30, 20, 17 and 15 m on a 40 m end-fed half-wave: SWR 1.09 to 1.56 on 40, 20 and 15 m, about 2.4 to 2.5 on 30 and 17 m, with band boundaries — SWR sweep — tick the bands, run it, and see the whole curve. A 40 m end-fed half-wave: low on 40, 20 and 15, high on 30 and 17, as it should be.

What it does

An SWR sweep for tuning an antenna in the field. Tick the bands (the ones you’ve enabled are ticked for you), see how long it will take, and run it: the station sends a short carrier at each point and plots SWR from 1 to 6 across every band you chose, with the band edges marked and the lowest point on each band named. Adjust the wire, run it again, and your last run stays faintly behind the new one. Stop ends it at once. Needs the PoE‑P4 and a QMX; set the QMX’s Tune power to 25% or more for a true reading.
A full browser UI. Operate, queue, tune, and download logs from Safari or Chrome. Tap any callsign to see its grid, bearing and distance, your past QSOs with it, and a link to QRZ.com.
An offline map. It shows great-circle paths to every grid you’ve worked, plus the grayline. With internet, it adds live POTA/SOTA spots and NOAA space weather.
You can still operate while transmitting. The decode list stays live, so you can queue the next QSO. Power and SWR are shown on screen.
A CQ calls as many times as you set, then stops. Stations that answer are worked first, and every message in the queue goes out a set number of times, which you can change on its row.
Logs are safer, and easier to get off the station. Download a day’s .adi file straight to your phone and upload it to whatever logging software you use. Direct QRZ.com logging is coming soon. A QSO logs the other station’s grid even when the exchange never carried one, from the last grid it sent in the past four hours.
It never logs what didn’t go out. If the radio can’t be keyed when your slot starts, nothing is sent, no try is used, and the message goes out in its next slot once the radio is back. Stop ends a transmission on the air at once.
Plays well with an amplifier. Settings › Amplifier sets how long the radio waits after keying before RF, and can recover from the QMX’s SWR protection tripping on an amplifier’s first transmission on a new band.

What’s verified, and what isn’t yet

Here is what has been checked on the air, on real hardware, and what hasn’t.

Verified on the air

Real FT8 QSOs on the headless PoE-P4 build.
The SWR sweep, on a PoE‑P4 with a QMX and a 40 m end-fed half-wave: 40, 20 and 15 m read 1.1 to 1.6, 30 and 17 m read above 2, as that antenna should.
Signal reports on WSJT-X’s scale, checked on the air at a POTA activation. Against WSJT-X’s own decoder on 984 recorded messages, 79% read within 3 dB of it.

Not yet, or not claimed

Decode sensitivity hasn’t been measured against WSJT-X or any phone app. Micro-FT8 decodes with Karlis Goba’s ft8_lib. We’ll publish numbers once we’ve measured them.
QDX hasn’t been tried. The firmware has a QDX backend, but it has never run against a real QDX; every QSO so far was with a QMX. KH1 isn’t supported.
Calling CQ a set number of times is new and hasn’t been checked on the air yet.
Some of the newest browser features, such as the map on a real phone and .local names on Android, are still waiting on field checks.
This is an early pre-release. We’re looking for feedback; it isn’t a finished release yet.

Coming soon

Deeper decode — using more of the ESP32-P4’s headroom for better recall on busy bands.
Per-band conditions — a band-by-band read alongside the space weather numbers.
QRZ.com realtime logging — upload completed QSOs from the browser with your own credentials (callsign links to QRZ are already in; this is the log-sync half). The radio never holds those credentials.

Downloads

Firmware images and a buildable source tree: Downloads. Setting up a station: Getting started.

Contact

Questions, feedback, or a bug to report: reach me, Jeff KB2SLO, through my QRZ.com page. For a bug, say what you tapped and when, and copy the Firmware and App lines from the app’s Settings.