Getting Started with Data Modes

Working amateurs around the world using data is a fascinating part of the ham radio hobby, and is definitely worth considering. On this page, we look at what the various amateur radio data modes offer, and how to get started using data.

Here’s a summary of the basics on how to start out operating the amateur radio digital modes.

Why data modes are worth a look:

  • Data tends to work well with low power
  • More bandwidth-friendly than voice
  • Helps with language barriers for non-English speakers
  • Electronic logging is often very easy with data modes


Getting started with data:

Here’s what you’ll need to get started with amateur radio data modes:

  • An Interface – See below
  • Cables to connect between the computer, radio and the Interface
  • A computer with a soundcard (mic and speaker sockets)
  • Software – There are various different packages depending on what mode you want to work
  • The right frequencies – Each mode typically has a dedicated frequency for each band


The Data Interface

The Interface is the device that connects between your radio and the computer.

Digimaster Pro
A Data Interface: The Digimaster Pro CAT Interface box

There are various types of Interface, and it’s important to get the right one for the job. Here’s what you need to know:

  • CAT – Computer Aided Tuning… these allow your computer to change the frequencies and settings on your radio
  • PTT – This means that your computer can use the Interface to get your radio to transmit
  • DATA – Your Interface needs to be able to handle data transfer and balancing the audio levels between the radio and computer. It also needs to support the baud rate used by the data mode in question
  • CW – If you’re looking to use your computer to send and receive Morse, check that your Interface supports CW
  • Connectivity – Make sure that your Interface is suitable to connect to your radio, and get the correct leads


Balancing the Audio

All of the data modes we’re covering here rely on audio being sent and received over-the-air. Your computer’s audio soundcard does much of the work. The key to working data modes is to get the audio levels to and from the computer to be ideal:

Level into computer: Make sure that the software is getting the right audio level from the computer. You may need to adjust the soundcard volume, input volume on the software, or the level from the Interface. Software will have an “ideal” range, and you should hit this

Level from the computer: You need to make sure that the audio leaving the computer is of the correct volume (and not distorting). You may need to adjust the soundcard output volume, or the transmit level from the Interface. You also need to make sure that your radio is not activating the ALC (Automatic level control) as this can alter the quality of the data being sent.

WSPR (Weak Signal Propagation Reporter)

This mode is a send-only mode. You send out, over the course of a minute, a data signal containing your location and callsign, and can then check online which stations received your signal.

WSPR Map showing signals from Essex

Want to give WSPR a try? See Getting Started with WSPR

JT65 / JT9/FT8

These modes are a little like WSPR, but they allow a two-way exchange. To avoid splatter with other transmissions, keep the power low (max 25 watts).

These modes allow sending short messages. With JT65, each “over” takes one minute. The newer FT8 is faster (an “over” every 15 seconds)

Messages are typically 13 characters long, and go something like this: “CQ with location, Reply with location, RST, RST, Report Received, 73, 73”

As with WSPR, the PC clock must be spot on. Keep your PC clock in sync with Dimension 4

A QSO with Japan on JT65


Standing for Radio Teletype, this mode supports two-way QSOs – you type in real-time, and your message is displayed at the other station almost instantly. It was the forerunner to PSK31.

A RTTY QSO on Ham Radio DeluxeA RTTY QSO on Ham Radio Deluxe
A RTTY QSO on Ham Radio DeluxeA RTTY QSO on Ham Radio Deluxe

You can play with RTTY either using Ham Radio Deluxe, or the rather more complex MMTTY


Stands for Phase Shift Keying with a bandwidth of 31.25Hz. This allows a two-way QSO, and typically uses macros for common phrases.

PSK31 Image 2
PSK31 using Digital Master on Ham Radio Deluxe

For more on PSK, see our PSK31 – The Basics page

Slow Scan TV

Send and receive images. Formats include Robot / Scottie and Martin. Images use around 3kHz of bandwidth and take between 1 and 2 minutes to download.

Sending an SSTV image using the MMSSTV application

Want to find out more about Slow Scan TV? See our SSTV – The Basics page


APRS /Packet

Packet data is sent in short bursts. The most common application for Packet data is for APRS (Automatic Packet Reporting System). You’ll need a TNC (Terminal Node Controller) to send and receive packet data

Map of APRS activity in Essex
Map of APRS activity in Essex

If you tune in to 144.800MHz, you’ll hear APRS packets containing status messages, locations and weather information. To use APRS, you’ll need a TNC, GPS receiver and either a Transceiver or the Internet.

Sending a packet with UI-View
Sending an APRS packet with UI-View
  • To check out Essex amateurs, see the map at :

Want to find out more about APRS in Essex? See our APRS in Essex guide

Data to the ISS

It’s possible to send and receive APRS packets from the ISS. To do this, you’ll need to be set up for APRS. These links will help too. If you’re interested, we can create a more detailed explanation of how to work ISS in packet.

More on working the ISS: Working the International Space Station

Smartphone software

There are applications available for iOS and Android devices for Packet, APRS, PSK31, SSTV and RTTY. Check iTunes Store or Google Play

See also: Handy iPhone apps for amateur radio use

Related Pages:


  1. Rowland Rees ( Rowli ) GW0RTR 16 May 2020 Reply
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