What fun, maybe a new trend ? How much did the vacuum containment structure weigh ?
This is where the “goat” comes in… Steve, WG0AT could bring
the whole HF station up the hill!
We brought a lot of old tube rigs up the hills for Field Day in the
old days (In a truck !)
73
John, K6YK
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I wonder how many shortwave activations with vacuum tubes took place so far.
Is there anyone who is using them in this manner?
73 Karel, OK2BWB
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Hi, I have one RA-200, would be fun to try it portable. It is a 3 men load to carry, and you need someone to pedal the generator.
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By chance, a friend just sent me newsletter about using radios to support the 1933 Everest climbing expedition. Many technical details, and some pictures.
The article is in the K9YA Telegraph and can be found at at K9YA Telegraph - K9YA.
I have attached a clip of the front page of the newsletter;
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From ancient times:
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Dynamotor 
I remember back in the 70’s I sketched out a design for a portable 2 metre rig using the 1.5volt filament valves (1T4, 1S4 etc) multiplying up from an 8 MHz crystal. I got as far as assembling the components but lost interest when I bought a Liner 2 and migrated to SSB. I’ve still got the valves somewhere.
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This 40m CW TX started out as a quick retro junk box project during the latest lockdown, but it has drawn me into revising my knowledge of class C operation through lots of tinkering! Currently producing 0.5W from 1.0W dc input. It uses two DL94 1.4v battery valves…
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I know that are Paraset spy radio fans who activate /p.
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Thank you, Éric.
The Armstrong triode regenerative detector (invented ín 1912), Hartley modification, my circuit to synchronize it with the transmitting Colpitts triode superVXO and some brain digital signal processing to suppress the unwanted sideband make Hejkalset a nest of clearly singing chasers. The shorter and the more linear the receive path is, the clearer the sound becomes. It was a great pleasure, even though I had to concentrate hard at first, to keep up with the wild communication arena. And straight keying is icing on the cake!
73
Karel, OK2BWB
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Tnx Karel for FB contact today
SA4BLM / Lars
MM0FMF, I wonder how many folks have seen or used a dynamotor?
Or even know what it is? My first 2-meter FM radio had a dynamotor
in it! 500 volts at 200 MA as I recall. And the receiver ran from a
vibrator supply. Just the dynamotor weighed more than any modern VHF radio!
73,
John, K6YK
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I first saw a dynamotor in 1973 when I was just out of short trousers. We had a radio club at my school and the teacher who ran it was into US WWII surplus. He had many dynamotors in basement rooms at the school. I often what happened to them after he retired and had to clean out his collection. Or when he died a few years back. I used to visit him when I went “home” to see my mother and his house was creaking under the amount of green radio gear.
They sell for stupid money now if you have a working one in nice condition. Still go for a good price if tatty.
This is how I remember them…
https://www.ebay.co.uk/itm/Vintage-Crosley-Dynamotor-for-PE-103A-Power-Unit-US-Army-Signal-Corps-6-12V-500V-/182945625882
The teacher was a real character… he’d worked at Windscale Works as a lab tech back in the fifties and had actually seen Plutonium metal produced for the UK Nuclear weapons. Not that many people can claim that.
Yes, sir! That photo looks familiar! I found a photo similar to my first
dynamotor powered 2 meter rig. Mine was a “LINK” but the Motorola
in the photo looks very similar. You wouldn’t want to be hauling this baby up the hill on your back to work 2 meter FM! This was a MOBILE unit of the late 1940’s-3arly 1950’s.
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This thread brings back memories; Started career in summer, between elementary and junior high school as an apprentice in a radio shop. The police were changing over from AM, just above the broadcast band, “calling all cars” to the new Motorola VHF FM. So spent a lot of time drilling holes in cars and brand-new Harley Davison cycles! As a newly minted ham in 1955, carried a BC-611E handy-talky to call CQ on 75M (3.885 Megacycles) in distant towns, to ask about where to eat, stay, etc. Later, had Morrow twins with a dynamotor HV supply for transmitter, vibrator supply for the receiver; This in a '57 Chevy.
Best, Ken K6HPX
Very swell, Ken! Yeah, those were the days. We got those LINK rigs
from the Sacramento Co. Sheriffs when they upgraded in around 1964.
I took out the dynamotor and built an AC supply inside the transmitter.
It was my only 2 meter FM rig for years. We had one simplex frequency in Humboldt county and that was it. No repeaters, etc.
In mobile service, a 6-volt model drew 82 amps on transmit! What a
beastie! (keep the engine running!)
73, John
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Hi Adrian, it looks like I may be building the same circuit as you. Was this the “Cigar Box Amateur Transmitter” from March 1955 Practical Wireless ? I’d be interested in your experience. I’m looking to build a similar level RX and put them both into one box, running on 20m.
73
Rich (G0GGA)
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Hi Rich,
Welcome to the Reflector!
Yes, that’s the circuit that I built - I used torroid cores for L1 and L2, and a link coupling for the output as I didn’t intend to use it with a half wave wire antenna.
I haven’t attempted a receiver to go with it yet, and the nearest thing to a QSO has been sending “CQ” and seeing it pop up on the RBN.
It has a distinctive “chirp” when keyed, which I suspect is the battery voltage sagging at key down, but I haven’t investigated yet - I have heard worse!
Good luck with the build, and please let us know of progress…
73
Adrian