Quote:
Originally Posted by Steve McVoy
I was thinking about 50s UHF converters. I don't know of a single one that had a RF amplifier. Given the problems with UHF reception and the very poor noise figure of converters with no RF amps, why didn't at least one manufacturer make a premium model with an amp? They had the technology and it wouldn't have been terribly expensive.
|
Steve,
The first UHF converter designed for the Bridgeport CT UHF field trials in 1950 had an RF amp. It was a 6J4 triode in a grounded grid configuration. It was quite involved, an RF amp, input mixer/osc, two IF stages and an output osc/mixer to produce a 21Mc signal to the TV IF. The 1950 RCA Blue Book (pg 220) has a paper describing the converter.
Don't know if that design was actually used in the field trial, as the convertor I have, dated 4/50, has the two IF and mixer/osc tubes but not the RF amp.
The paper also mentions the UHF test converter used in the Washington DC field trial in 1948 as having an RF amplifier, but again the unit I have from that trial doesn't have an RF amplifier either.
Chuck