[ARC5] RU receiver question

Hubert Miller Kargo_cult at msn.com
Thu Oct 19 23:08:48 EDT 2023


Nice photo posted by Taigh. 
But my question about the RU, for people who have actually used it: is the selectivity, on CW, effectively much better
than on AM ? On AM mode, it seems to me pretty useless. I mean, 3 tuned circuits at say, the Army air-ground freq
of 4495 ? 3 tuned circuits at 5 MHz? That's okay for the front end of a synchronous detector WWV receiver or a 
bandpass in front of some other selectivity device. 
I know it's not a product detector, and the beat note is in the audio range. I am still puzzled and perplexed how this
little selectivity can be practical at HF.
BTW, i think there's only one other military aircraft straight TRF receiver used during the war, and that was the FuG ?
( 4 ? ) used in the Stuka dive bomber. Japan's aircraft radios were often not up to much of a job, but they used no
TRFs. ( I do not count the UK TR-9 as a "straight TRF". )
AND years ago i asked Pete Peterson, of Seattle, who flew in this exact position in the photo, and he just answered me, 
"Well, i thought it was a pretty good receiver", which left me puzzled still. 
I still have several RU. I suppose i should just power one up, circumvent the AGC so i can skip the negative bias voltage,
and find out for myself. 
-Hue Miller 


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