|courtesy: WA3TTS & NO3M|
In Eric's own words:
I had a 1920/1930s style Field Day setup this weekend and a bunch of guys over. 80M doublet with homebrew open wire line (approx 550 ohm), the transmitter was a 27-24-24-865 job more or less straight out of July 1931 QST, but with a Hartley instead of crystal oscillator. 27 tuned to 80M, first 24 to 40M, second 24 also 40M, and the 865 on 40M. About 10W. Never did get a chance to try her out on 20M by using the second 24 as a doubler.
I also built the complementary amplifier using a 203A from the August 1931 QST article. I had not even tested the amplifier, only having been finished at 1AM Saturday morning!! It is somewhat different in that the grid circuit is composed of the driving rig's antenna coupling coil/cap, re-wired to be in parallel, not series, of course. It was coined as being a good amp for any existing power oscillator or MOPA, We did a quick job of neutralizing while the gang was here and fired it up..... no modern measurement devices in sight, so we were only going on RF current. 0.9 amps into 50 ohm (pre-tuned the homebrew link coupled, balanced tuner with an analyzer beforehand)... so about 40 watts. I was hoping for 100W.... anyways, after most guys left, a couple of us starting messing around with it more, mainly tightening the output coupling of the MOPA and amp tanks. NICE! 1.45 amps, ie. 105W on 40M.
Anyways, I'll have a full writeup and photos on my website in a few days. We used an HRO5 for a receiver; everyone commented on how good it sounded and well it handled. Of course, this is from a bunch of guys that grew up with this stuff and/or has owned one at one time or another. Everyone had a great time and lots of good discussion and visiting, including 153 QSOs with that pile of junk!
73 Eric NO3M
Most will agree that Eric's station is far from a "pile of junk" as his superb homebrewing skills are clearly evident! Setting up this old style gear can be challenging at any time, but doing it for an outside weekend operation must have been a ton of work. Well done Eric!
For more information about building and operating '29-style transmitters, see the links on my blog sidebar.