Ham Digital Communications

Digital Introduction

by Walt Fair, Jr., W5ALT

Some History - From a Personal Viewpoint

I've been playing with digital communications modes in varying degrees since the late 1970's. In the early 1980's, with the advent of personal computers, digital experimentation became much easier and dedicated multimode terminal node controllers (TNC's) became fairly common.

In the late 1980's, while living in Slidell, LA, I ran a digipeater on 2 meters which seved as a link between New Orleans and the Mississippi Gulf Coast. Some of my early experiments involved linking a telephone BBS in FidoNet to my 2m rig and allowing ham related message forwarding via either telephone lines or ham radio. Since the National Weather Service office was close to my home, they were able to load hurricane advisories via the telephone BBS and they were automatically forwarded via packet radio across country.

In 1990 I was transferred from the New Orleans area to Houston and had to disassemble my packet and digital equipment for the move. On arriving in Houston and getting settled in, I put the telephone BBS on line and set up my packet and digital ham gear. But the situation in Houston was different. There were plenty of digipeaters around, thanks to the Johnson Space Center ham group, and my station, without a good antenna, was really pretty superfluous. As a result I didn't keep the digipeater and TNC on the air very much. Then I started my own business and between work and family responsibilities, I was off the air digitally for nearly 8 years.

When I got back active in digital communications again, I was shocked at the changes that had taken place. I assumed that the ham digital world had passed me by and that great technological advances had taken place that I missed out on. Boy, was I surprised! It apeared that the digital ham revolution had nearly stagnated. There were no digipeaters, there was no one interested in digital communications on the local VHF repeaters.

It appeared that digital technology had passed over most hams without leaving any lasting mark.

What I did find out out is that most hams were using computers - of course that was no surprise. But the little bit of digital experimenting that was underway appeared to be geared toward adapting the emerging internet technology with amateur radio. The rest of the digital activity seemed to be in the hands of a small group of hams, with the exception of the development of the "sound card digital modes" for use on HF. It seems that during my absence from digital modes, the entire development effort had been undermined to the point where nothing was being done.

Some Philosophy

So what should be done? I'm afraid I don't have all the answers!

It is my hope that the excitment of amateur digital communications can once again be ignited. Much of the world seems to have fallen in love with the internet - and I'm no exception. You are reading these notes over the internet and I have maintained my own servers on the internet since the early 1990's when most people didn't know what it was. There's nothing wrong with the internet.

But the internet is NOT ham radio!

It is my hope that some of the hams that are still active can rise to the challenges of using digital technology for ham radio. There are important challenges that await those who are willing to experiment with digital communications techniques. Such things as pulling weak signals out of noise, overcoming the effects of propagation and fading on the HF bands, efficient use of our limited spectrum, and much, much more.

In my mind there is no doubt that the computer has changed the world. But there also is no doubt that we, especially as hams, need to figure out how to apply computers and digital techniques efficiently to augment and improve amateur radio communications. In other words, rather than emulate other communications services, we need to develop methods that are uniquely ours. This can only be done by understanding technology, thinking in new ways about communications and data, and by trying to push the envelop on our limitations a little more.

A Challenge

We, as hams, have an advantage over commercial developers. (And yes, I have done commercial development.) We are able to do things simply because we want to, because it's a challenge, because we think it's "the right thing to do." It is time that we "amateurs" put ourselves to the task and bring amateur radio fully into the new millenium, by developing solutions that exploit the benefits of amateur radio, not just try to emulate what others have already done.

It is my hope that some of the information on this web site might help take a few faltering steps in that direction. But as I said, I don't have all the answers, so anyone interested in discussing such things automatically has my attention!

Acknowledgments

First, I humbly acknowledge the input of lots of people, from personal and on-line discussions, to magazine articles to textbooks. I've drawn extensively from things I've read in both QST and QEX. You can be assured that there is nothing much here that I have invented or have any claim of originality.

However, if you find some errors, mistakes or blunders, I must accept full responsibility. Any comments on these notes should be addressed to me at w5alt@comportco.com.

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