R-1051 Page

I don't know quite why I am so fascinated with these receivers. They are terrible band-cruisers, which is about all I do. You have to know exactly what frequency you want to listen to, and even then, you can get a sprain trying to crank all those knobs around.

The other thing is that it has absolutely the wackiest, Rube-Goldberg frequency selection mechanism. I swear that easily 65% of the device is just in the frequency synthesizer and not in the amplification, detection, AGC or other signal path circuits. I guess they had a reason. These days, we would have a very high frequency oscillator with a couple of banks of counters and a PLL and that would be that.

Note that this receiver is all transistorized except that the RF amplifier stage has two vacuum tubes (!) - a 6BZ6 and a 6AN5. Since we don't have access to the original engineers, we can only guess at why these are tubes and not transistors. Note that they do use the 2N2222 in this receiver, so they had transistors that could respond easily over the required frequency range (although possibly requiring a cascode topology to get high gain at 30 MHz). The only thing I can figure is that the tubes are much less sensitive to static and to transient voltage overload from the antenna, and presumably less sensitive to ECM.





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