FT8 Operation

FT8 Operation

FT8 is a popular weak‑signal digital mode. The zBitx decodes and transmits FT8 right on the radio — you don't need a separate computer running WSJT‑X for basic operating, though you can still use external software over CAT if you prefer.

This page covers FT8 from the front panel and the web interface. (You can also run WSJT‑X on the Pi's desktop or an external PC — see Voice & Digital Modes and USB Mode.)

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Before you start

Make sure you've set your callsign and grid in Setup — FT8 exchanges use both. Accurate time also matters a great deal for FT8 (see the timing note near the end).

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Getting on FT8

1. Set the MODE to FT8 (tap MODE on the main screen until it reads FT8).
2. Tune to a standard FT8 frequency for your band. Common ones:
   • 40 m: 7.074 MHz
   • 20 m: 14.074 MHz
   • 30 m: 10.136 MHz
   • 17 m: 18.100 MHz
   • 15 m: 21.074 MHz
3. Watch the FT8 decode list populate as stations are received. Each line shows a decoded station and its message.

The decode list is color‑coded so you can quickly see what's what — for example, stations calling CQ, stations responding, and messages that involve your callsign stand out.

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Calling a station (tap to call)

The zBitx has a tap‑to‑call feature that makes working FT8 fast:

1. When you see a station you want to work in the decode list, tap their line.
2. What happens next depends on the 1‑TAP setting:
   • 1‑TAP ON (the default) — tapping the station immediately starts calling them. The radio builds the correct reply and begins transmitting on the next cycle.
   • 1‑TAP OFF — tapping just highlights the station. You then press the encoder knob to confirm and start the call. This gives you a "look before you leap" step.

You can change the 1‑TAP setting any time from Menu → 1‑TAP (or in the Radio menu). Turn it OFF if you find yourself calling stations by accident; leave it ON for the quickest operating.

Tip: You can also move through the decode list with the encoder knob and press it to select — handy if you'd rather not tap.

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Working a full QSO

FT8 QSOs follow a standard, automatic sequence. Once you start calling a station, the radio steps through the exchange:

1. You call them (your call + their call).
2. They reply with a signal report.
3. You send your signal report (often "R" + report).
4. They send RR73 (roger, best regards) to confirm.
5. You send 73 to close.

The QSO is then logged. The exchange is largely hands‑off once you initiate it — the software handles the timing and the standard message sequence.

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Using the web interface for FT8

The web interface gives you a bigger, more comfortable FT8 experience on a phone, tablet, or computer. It shows:

• The decode lists — Band Activity (everything heard) and RX Frequency (activity on your frequency or involving your call).
• A grid map showing where stations are.
• DX spot indicators.

To call a station in the web interface, click its line — the same tap‑to‑call idea applies. Each decoded transmission appears once per pane (your own transmissions included).

See Voice & Digital Modes for how to reach the web interface.

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Timing is critical for FT8

FT8 transmissions start on precise 15‑second boundaries, so your radio's clock must be accurate — ideally within a second or so of real time. The zBitx keeps time synchronized over the network when it has an internet connection.

• If your decodes look sparse or you're not being answered, suspect the clock first. Make sure the radio is connected to WiFi so it can sync time.
• Without a network connection, the clock can drift and FT8 will decode poorly or not at all.

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Power and antenna for FT8

FT8 is a 100%‑duty‑cycle mode — it transmits at full power for the entire 15‑second slot. On a 5‑watt QRP radio this is fine, but:

• Keep an eye on the SWR — a bad match is harder on the finals during long key‑downs.
• FT8 is a weak‑signal mode by design; 5 watts works extremely well. You do not need more power to make contacts, even DX.
• If you're running the radio for long FT8 sessions, make sure it has adequate ventilation.

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Troubleshooting FT8

Symptom	Likely cause / fix
No decodes at all	Wrong frequency, wrong mode, no callsign entered, or antenna problem. Confirm you're on the band's FT8 frequency in FT8 mode.
Decodes but poor / few	Clock drift — connect to WiFi for time sync.
Not getting answered	Clock timing, or too little activity. Try a busier band/time.
Accidentally calling stations	Turn 1‑TAP OFF so taps highlight instead of call.
Web decode list looks doubled	Update to current software — a fix ensures each transmission shows once per pane.

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Related: CW Operation » · Voice & Digital Modes » · WiFi Setup »