Sunday, March 22, 2009

Signals from Hell

The great thing about amateur radio is it’s almost impossible to get bored. Tired of SSB?...brush off (or brush up on) your CW skills. CW not your scene? No probs, there’s VHF/UHF, repeaters, IRLP, EchoLink and numerous HF digital modes to try. A couple of years ago, a friend lent me his RigBlaster to try out. I was soon hooked on PSK31 and was having a lot of fun using the keyboard to communicate instead of the mic or keyer. This led to some dabbling in that older, but still common digital mode, Radio TeleType or RTTY. I remember years ago, before computers were as common in the shack as solder splatter on the floor, a ham friend who was into RTTY had a room full of vintage Teletype equipment salvaged from some telecommunications centre somewhere. Back then the only way to copy the strange sounding signals was to bring these great beasts to life. The things clattered, the house shook, the dog was barking, the paper spewed! As fascinating as it was, at the time I couldn’t see myself trying something like that! Much easier to key the mic and say “CQ”! Well, now the computer and greatly improved and simplified interfaces like the RigBlaster have made RTTY and many other digi modes much more accessible. I spent part of this weekend making contacts on the BARTG (British Amateur Radio Teledata Group) RTTY contest. I made just 39 contacts, but I can just imagine how much paper would have been snaking across the floor had this been the “olden days” of 20 years ago!

I’d heard tell of this other mode with the sinister name “Hell”. I thought working “hell” was when you were trying to crack a DX pile-up with a noise level of S9 and heavy QRM! Well, this “Hell” is actually short for “Hellschreiber”, and it’s anything but new. It was first developed in the late 1920’s by its namesake Rudolf Hell (wonder what his priest though of the family name?!), and is similar to facsimile. During World War II, the Germans often used Hellschreiber in conjunction with the Enigma machine and the equipment used to send and receive the mode looked similar to that of the Enigma. Move ahead to today and modern computer-to-radio interfaces and sound card technology allow this to be replicated on your monitor. Unlike many of the digital modes, that use variations of phase-shift keying, “Hell” uses on-off keying to “paint” a picture of letters, word and symbols. In that way it’s very similar to Fax and even CW. It may be based on old technology, but it’s pretty cool to watch!

I had considered playing around with this mode once I got around to learning a bit more. But, after a post on 73s.org by Jeff, KB3ELT mentioning he’d made his first Hellschreiber contact, and seeing there was a Hell contest underway this Saturday, my interest was piqued. I actually found that the CD that came with my recently acquired RigBlaster Plug-n-Play contained the popular Hellschreiber software by IZ8BLY. I loaded it up and within a few minutes was watching words being “painted” on the signals. Unfortunately, I had to move on to some other activities and didn’t get a change to try a transmission before the contest ended. Efforts to find other Hell signals were unsuccessful, partially due to the heavy RTTY from the BARTG contest. Maybe next weekend I’ll have my first “Hell-ish” radio encounter!

There’s a good website by WB8NUT that explains the various digital modes used my amateurs complete with links to software downloads.

So, if you’re getting stuck in a rut with your operating practices, try something new!

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