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A Quick Guide to FT8, JS8 and FT4 Digital Modes

Getting Started with FT8, FT4, and JS8Call

To operate digital modes such as FT8 and FT4, you’ll need to install the WSJT-X software on your PC. For JS8, the required application is JS8Call.
 

Both WSJT-X and JS8Call are open-source programs designed for weak-signal digital communication by amateur radio operators. Typical usage involves a standard SSB transceiver and a personal computer with a soundcard (or equivalent interface). All programs are available free of charge.

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Whether you're simply looking for a high-performance isolated USB sound card like our Digimode-3 interface, or want the added convenience of CAT control combined with premium audio performance in our Digimode-4 interface, we offer tailored solutions to suit every shack.

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Please check our Alinco, Icom, Kenwood, Ten-Tec, Xiegu and Yaesu shops to see our great value interfaces.

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WSJT-X Overview

WSJT-X (“Weak Signal Communication, by K1JT”) supports a suite of digital protocols optimized for:

  • EME (moonbounce)

  • Meteor scatter

  • Ionospheric scatter

  • LF, MF, HF, VHF, and UHF propagation


It can decode fraction-of-a-second signals reflected from ionized meteor trails and steady signals more than 10 dB below the audible threshold. WSJT-X integrates nearly all popular features from the legacy WSJT and WSPR programs, while adding rig control, logging, and advanced decoding capabilities.


Supported modes include: FT4, FT8, FST4, FST4W, JT4, JT9, JT65, Q65, MSK144, and WSPR. For full details, visit the WSJT-X homepage and its documentation.

WSJT-X can be downloaded from here
 

 

JS8Call Overview

JS8Call is a derivative of WSJT-X, but with a modified protocol that removes rigid time slots and structured messages. Instead, it functions more like PSK31, enabling keyboard-to-keyboard chat, free-form text, and directed calling.
 

JS8Call supports:

  • Message relaying

  • Beaconing

  • Store-and-forward messaging
     

It retains the ~50 Hz bandwidth and weak-signal performance of FT8, but offers greater flexibility and operator control, making it ideal for off-grid, emergency, or long-form communication.

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JS8Call can be downloaded from here

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Comparing FT8, JS8, and FT4

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FT8 – Fast, Structured QSOs

FT8 is a fixed, structured protocol designed for rapid, automated exchanges. Think of it as speed dating for hams—you exchange callsigns, grid locators, and signal reports in a 15-second cycle.

  • Ideal for DXing, contesting, and propagation studies using tools like PSKReporter or GridTracker

  • Uses 8 carriers spaced 6.25 Hz apart, fitting into a 50 Hz bandwidth

  • Transmits 77 bits of data per cycle—extremely efficient

  • Requires precise timing via NTP sync to align with global time slots

 

JS8Call – Conversational Messaging

JS8Call builds on FT8’s modulation but removes its rigid timing structure. It’s more like PSK31, enabling:

  • Free-form text

  • Directed calling

  • Message relays and beaconing

It’s perfect for off-grid communication, emergency use, or casual keyboard chat, while maintaining FT8’s weak-signal robustness.

 

FT4 – Contesting Speed Demon

FT4 is the sprinter of the WSJT-X family. It uses a 6-second cycle—more than twice as fast as FT8—and a slightly wider bandwidth (~90 Hz).

  • About 3.5 dB less sensitive than FT8

  • Optimized for rapid-fire QSOs in contests and pileups

  • Fully automated and structured—no free typing, just fast exchanges

 

Summary

If you’re focused on efficient QSOs, flexible messaging, and contest performance, then FT8, JS8Call, and FT4 cover nearly all modern weak-signal use cases. Whether you're chasing DX, prepping for emergencies, or logging contacts at lightning speed, these modes offer a powerful toolkit for today’s digital ham. Below is a quick comparison table to show you the features and differences between the 3 modes.

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Active Frequencies for FT8, FT4, and JS8Call

 

The table below lists the most commonly used frequencies for weak-signal digital modes across amateur bands. Whether you're chasing DX, joining a contest, or experimenting with JS8Call messaging, these are the go-to spots for activity. Frequencies may vary slightly by region, so always check your local band plan.

 

Tip: FT8 and FT4 frequencies are often crowded—overflow frequencies listed here can help you find clearer airwaves. JS8Call users typically operate just above the FT8 segments.

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So what do we do next?

 

Now that we’ve covered what FT8, FT4, and JS8Call are—and explored when and where to use them—it’s time to move from theory to practice.
 

Next, we’ll look at:

  • How to set up your PC and interface for reliable digital mode operation

  • The rules of the road for on-air etiquette and timing

  • Proven best practices for making smooth, efficient QSOs and getting the most out of each mode
     

To get started, you can review our WSJT-X hardware setup guide here, which walks through everything from software configuration to rig control and timing sync.
 

Whether you're using a simple isolated USB sound card like our Digimode-3, or a full-featured interface with CAT control like the Digimode-4, we’ve got the tools and guidance to get your station on the air.

 

FT8 & FT4 Operational Mastery (WSJT-X)

  1. How To Setup WSJT X For FT8 And FT4
    A concise walkthrough covering clock sync, auto-sequencing, and waterfall optimization. Great for understanding split operation and transmission weighting.

  2. FT4. First use of WSJT-x 2.1.0 rc5
    A quick demo showing FT4 in action, with frequency setup and timing differences from FT8.

  3. FT8 & FT4 for Beginners & Established Users- 01/19/2023
    Covers band maps, transmit macros, and Fox/Hound mode—ideal for contesting and DXpeditions.

  4. WSJT X Setup tips and tricks for FT4 FT8 contacts using
    Practical advice for making reliable contacts, adjusting waterfall settings, and managing band activity. Especially helpful for FTdx10 users.

  5. Ham Radio: WSJT-X Tips and Tricks
    Explores decoding strategies, waterfall optimization, and operator styles. Includes insights on colour coding and decode behaviour.

  6. Mastering your FT-dx10 with WSJT-x for FT8/FT4
    Demonstrates advanced rig control, pre-set management, and live QSO examples. Excellent for refining station responsiveness

 

JS8Call Operational Tutorials

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