RSGB Transistor Four. - UK Vintage Radio Repair and Restoration Discussion Forum

G6Tanuki · 9th Dec 2022, 6:04 pm

Looking through a mid-60s RSGB Handbook, I came across this. A kind of "Super-gainer" - a traditional superhet frequency-changer-down-to-455KHz with a diode detector and shuffling the IF-stage into random oscillation to provide a 'BFO' and CW/SSB detection.

Denco coils for the frequency-changer, it supposedly covered both 1.8 and 3.5MHz, but I guess you would have needed safecracker-levels of skill to tune it.

I'm tempted to do a 'revised' version of it - using modern Silicon transistors of course [the original was cursed by whiskery AF117-types] and replacing the Denco coils/wide-swing variable capacitor with some ferrite toroids and separate RF/LO tuning using capacitors with only a few tens of pF swing.

Did anyone ever build this?

9th Dec 2022, 6:04 pm	#1
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	RSGB Transistor Four. Looking through a mid-60s RSGB Handbook, I came across this. A kind of "Super-gainer" - a traditional superhet frequency-changer-down-to-455KHz with a diode detector and shuffling the IF-stage into random oscillation to provide a 'BFO' and CW/SSB detection. Denco coils for the frequency-changer, it supposedly covered both 1.8 and 3.5MHz, but I guess you would have needed safecracker-levels of skill to tune it. I'm tempted to do a 'revised' version of it - using modern Silicon transistors of course [the original was cursed by whiskery AF117-types] and replacing the Denco coils/wide-swing variable capacitor with some ferrite toroids and separate RF/LO tuning using capacitors with only a few tens of pF swing. Did anyone ever build this? Attached Thumbnails __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.