Digital Communications

These are exciting times for Amateur Radio.  Take part in it! While most hams are familiar with SSB and CW modes, there are many other communication modes that have been around for sometime, plus new ones, that can be explored. Old interests may even be reignited! It isn't all Morse Code and Voice.   There is a lot more in amateur radio now to capture one's interest!

The uniqueness of each mode will require the learning of new operating skills. In so doing, new doors will be opened and new friends made!  Have fun!


This is the fastest growing of all of the ham radio modes. While PSK31 is most popular on 20m, some activity does occur on other HF bands and  6m.

It all started in 1996,Peter Martinez G3PLX created PSK31 which offers the best of RTTY and Morse modes. PSK31 stands for "Phase Shift Keying, 31 Baud.

The number "31" is the extremely narrow bandwidth occupied (to be more exact 31.25Hz) by the PSK31 signal. By comparison, most other modes have a bandwidth of 300 to 500Hz. Narrow CW filters are used. This new HF digital mode enables communications, keyboard-to-keyboard between amateur radio operators.

While working conditions are usually noiseless with no QRM, like any digital mode, PSK31 is also vulnerable to interference. For example, polar region ionospheric disturbances can affect phase stability by producing a very rapid flutter, deadly to PSK31 signals. It should also be mentioned that PSK31 radio stations require less power and smaller antennas to operate.

In 1998, Peter Martinez developed the first software program to use with the PC sound card making this mode much more attractive to hams. To get on the air, all one needs is FREE software, a stable HF transceiver, PC with Windows and a sound card. It is important to select the latest version software compatible with your PC sound card. Two shielded audio cables are needed to interface your transceiver and computer. For transmit audio, a shielded cable is required to connect your sound card's speaker or line output jack with your transceiver's accessory audio input.

There are a few PSK31 operating techniques that must be learned when dealing with such narrow bandwidth and good weak-signal. It is vital that the receiving station be in sync with the transmitting station. Tuning in a PSK31 signal takes practice.

For help on how to do this, read  PSK31: A New Radio Teletype Mode July/Aug1999, pp 3 - 9.

PSK31 signals have their own distinctive sound. You must learn to recognize their high-pitched warbling sound, as you try to tune them in. While PSK31 activity can be found on many bands, most of the action is on 20 meters between 14.068 and 14.080 MHz.

For downloads and more information, visit these excellent PSK31 websites:

Peter Martinez G3PLX, developer of PSK31

Moe Wheatley AE4JY, WinPSK, version 2.11

HAMScope, multimode software

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The Automatic Packet Reporting System (APRS) was developed by packeteer Bob Bruninga, WB4APR, during the early nineties. Since then, it has grown to include many unique amateur radio applications which operate in real time:

The APRS shareware software can be downloaded by hams, specifically for amateur radio uses.

While one main use for the APRS system is to provide maps showing locations of stations, you don't need to have a GPS receiver to take part. Plots of your home QTH can be entered manually and then you can watch the locations of moving or mobile stations on maps on the PC screen.

All you really need is a PC computer connected to a TNC (radio data modem), all stations connected to the network can track the movements of all other stations in real-time. Beacon packets are continually transmitted by the TNC, which "broadcasts" information via a node or digipeater to all screens in the APRS network.

The nationwide APRS frequency is 144.39MHz simplex.

An excellent ARRL APRS resource

To view local APRS traffic over the Internet, visit

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The Delta Amateur Radio Society (DARS) now has the first Winmor server running in B.C. The HF dial frequency for the server is 7088.500 kHz. The callsign is VA7DEP. We invite all Winlink users who also have capabilities of Winmor to give it a try.

With this server now working, VA7DEP has the capabilities of handling Winlink mail on HF, VHF and D-STAR. For more info, please visit the DARS website.

Winmor Server Data
Posted Callsign Grid Square f0 kHz Mode Hours QTH
020119Z VA7DEP CN89ND 7088.5 WINMOR 1600 00-23 Delta BC Canada

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The Internet Radio Linking Project (IRLP) was developed by David Cameron VE7LTD of West Vancouver, B.C. in the late nineties. IRLP links VHF/UHF transceivers via Nodes/Reflectors connected to the Internet.


A Node consists of:


The link radio operates on either a simplex frequency but more often is connected to a repeater. The whole system can be contolled by amateurs using DTMF tones.

IRLP is becoming a very popular operational mode. There are many reasons for this.

IRLP Presentations

At the September 21, 2006 NSARC meeting, Dave Cameron VE7LTD gave an excellent presentation outlining the latest IRLP developments. Download the presentation materials here:

Presentation #1
Presentation #2
Presentation #3

At the June 5, 2008 NSARC meeting, Barrie Skeldon gave a presentation on IRLP and other VoIP modes. Download the presentation material here.

Visit the following IRLP websites for more information:

Internet Radio Linking Project (IRLP) and IRLP


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Questions or Comments? Please E-mail the Club

This page last updated: 2018-02-10