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TRUDO RADIO CLUB

FT8 & FT4


FT8 and FT4 in a nutshell

FT4 and FT8 are digital modes that allow radio amateurs to exchange messages so efficiently that they often seem audible even when you can’t actually hear them. They use short, tightly timed transmissions and clever encoding to make contacts possible under conditions where voice or CW would already disappear into the noise. These modes were developed by the WSJT‑X team, led by Joe Taylor (K1JT), Nobel Prize laureate and radio amateur. Together with Steve Franke (K9AN) and Bill Somerville (G4WJS), he introduced FT8 in 2017 as a highly sensitive mode for weak signals. FT4 followed in 2019 as a faster variant, specifically designed for contest use. FT8 is the “slow but super‑sensitive” mode. Each exchange takes 15 seconds and is ideal for picking up weak signals, working distant stations, and studying propagation. FT4 is the “fast brother” of FT8. With 7.5‑second cycles, it’s perfect for contests or moments when the band is busy and you want to make many QSOs quickly. Both modes are easy to use, require no exotic equipment, and open up a world of contacts — even when propagation is poor.

How to get started with FT4 and FT8?

Here is a practical, beginner‑friendly step‑by‑step guide to get you started right away.

1. Install the right software

For this you can use the free software JTDX, MSHV or WSJT‑X.
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JTDX main screen.
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MSHV main screen.
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WSJT-X main screen.

2. Connect your transceiver to your computer

You need two connections:
• Audio in/out (via a sound card interface such as SignaLink, SCU‑17 or built‑in USB audio)
• CAT control (for frequency and PTT control)

Many modern radios handle this with a single USB cable.

3. Configure WSJT‑X correctly

• Select your radio in the settings menu
• Choose the correct COM port and baud rate
• Check if PTT works (CAT or VOX)
• Set your sound card under Audio (Input = radio, Output = radio)

4. Synchronize your computer clock

FT4 and FT8 rely on strict time slots. Use a time sync tool such as:
• Windows Time Service
• Meinberg NTP
• Dimension 4

A deviation of more than 1 second can already cause problems.

5. Choose the correct frequency

Select FT8 or FT4 and a band in the software. The program automatically tunes to the recommended frequency.

6. Listen, decode, and start

• Click Monitor to start decoding signals
• Wait until stations appear
• Click on a station you want to work
• WSJT‑X automatically fills in the messages
• Press Enable Tx to start the QSO

7. Log your contact

WSJT‑X, JTDX and MSHV can log automatically, but you can also link your log to logging software such as DXLab, Log4OM, N1MM or HRD.