For one weekend in May, the landscape of Dayton, Ohio is dominated by ham radio operators. The Dayton Hamvention (“ham-convention”), sponsored by the Dayton Amateur Radio Association, is the preeminent gathering of hams from around the world. This is where industry rolls out new products, friends gather to catch-up, and old equipment is “re-distributed” amongst willing parties in the sprawling swap meet which subsumes the entire Hara Arena parking lot where you can find almost anything and meet some of the most interesting people.
Inbound vehicles
Driving in from the East Coast, you start seeing vehicles with massive antennas tacked-on, and call sign license plates in Eastern Pennsylvania. By arrival, the motels and Waffle Houses are choked with RF hobbyists. At rest stops and fast food outlets along the nations major transit routes you can identify like-minded enthusiasts quite easily. The only question you need to ask is “you going to Dayton?” And woe be it to the lonely soul who just couldn’t make it this year.
Convention
Since its birth in 1952, a unique subculture has developed around the event. An attendee can sit in on one of the expertly delivered forums; topics range from restoration of vintage equipment, to interface with orbiting satellites, to integration of software-defined radios and Rasberry-Pi into daily activities. In the swap meet there are used radios for purchase by the metric-ton, or you can take home the latest offerings from the major retailers. There are events planned for spouses and children, and opportunities to take the licensing exam to get on the air.
Building radio gear from scratch
Many people who have designed and built their own radio gear from scratch have yet to post it on the web.
Custom power cart for hauling old test gear
David, KD8NON, had a problem at Hamvention a few years back. He bought so much vintage test gear that he nearly killed himself trying to lug it back to his car. To fix this problem he developed this motorized wagon that uses a scratch-built VFD drive (MOSFETs and LM324 comparator and other things), a small crane motor, and a marine battery. He even welded the frame himself. The handle on this cart uses an old throttle position sensor for adjusting the speed of the cart. David has been using this for over 5 years at Hamvention to lug his “boat-anchors” home.
Green radios
One aspect of amateur radio is to restore and maintain old military surplus radio gear. It is a tradition since the second world war when, for the first time, really great equipment was widely available to all amateurs for low cost and the time it takes to do some minor hacking to get the gear on the air. At Hamvention you can play with lots of military gear and someone is always willing to let you crank the radio (to power it!).
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Painstakingly restored AM transmitter
Ever wonder what happens to old AM broadcast transmitters? Highly motivated amateur radio operators procure them, fix them up, and hack them to work on the lower amateur bands. There’s nothing like a gigantic AM broadcast transmitter in your garage.
You can buy anything here
The gratification that comes from buying something marked “as-is, condition unknown,” nursing it back to health in your hotel room, and making it work that same night is fantastic.
More tomorrow!
Technical seminars on vintage radio repair, how antennas work, meeting up with old friends, and making new contacts, or finding that one elusive piece of test gear. It’s all happening this weekend at Hamvention.
We’ve had some great weather this year! 80F and partly sunny most of the day except for a brief (10 minute) downpour. BTW, I found something at the Hamvention that most likely nobody else has…. my wife! We met there in 1976, married in 1979 and have been going strong ever since!
Ah, yes.
“The gratification that comes from buying something marked “as-is, condition unknown,” nursing it back to health in your hotel room, and making it work that same night is fantastic.”
Just kidding;-)
Finding a like minded mate makes the journey fun!
I hope that some of the talks are recorded and uploaded to Youtube like Defcon does.
I went to the Dayton Hamvetion in the 1990’s and bought a Data I/O paper tape reader for $20 – which I thought was a high price then, but later when I got it to work with two external power supplies (+5V, +/-12V and 24V) and was able to read my paper tapes, I felt was money well spent.
“There’s nothing like a gigantic AM broadcast transmitter in your garage.”
Especially if it gets cold where you live.
Doesn’t even have to by AM. Our radioclub has a shack for contesting at +1000m. It gets quite cold in the winter. Last year they took onboard a local FM broadcast station to get some extra € into the club. With 8kW at the antenna the heat from the power transistors is more than enough to keep the interior (5m x 5m) comfortably warm. No more lugging up and splitting of firewood required!
Whats that green thing with all the slots in the right photo at the bottom? Going from size I can figure out its for microwaves but was is it exactly? antenna? some kind of bandpass filter unit?
That Collins AM transmitter is a BEAST; got to see it up close yesterday morning when the flea market opened. Only my third time going to Hamvention, even though I’m only 300 miles away and have been licensed nearly a quarter century.