Homebrew all-mode HF transmitter with a pair of 6KD6 sweep tube finals (above) from 1974 when I used to operate as DU1AFS.
I've been using a 1950's vintage Collins KWS-1 as my daily transmitter for almost 20yrs now. It likes to drift a few hundred hz over 2 or 3 hours. This was state of the art in 1956 but nowadays people get very concerned when they hear someone drift that much. Therefore I decided to upgrade its frequency stability to be at least equal to modern rigs. I designed a homebrew DDS frequency control board for the KWS-1 using an AD9851 chip with OCXO reference.
Also added an AFC stabilizer to the VFO tied to the same OCXO reference. The KWS-1 still works just like before and the modifications are completely transparent but the OCXO now makes the 1956 transmitter extremely stable at 0.1ppm.
AFC control unit as installed on top of vfo (above).
KWS-1 power supply with access door open.
Popular washing powder since the late 1800's until the mid-1950's, the origin of the name for the Collins KWS-1 and 75A4 twins. Fairbanks called the twins Goldie and Dusty during their advertising campaign.
Homebrew remote antenna tuner in weather proof container located outdoors.
7971155 Last modified: 2017-03-17 00:17:16, 2044 bytes
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