A Deluxe Version of Stoner’s “The Novice Q5-er”
I used a variac to bring to life the BC-453 conversion with preselector that I purchased at the Shelby HF thanks to Nick England’s prodding and nudging.
After getting back home I took a close look at the receiver and found a small tag that explains the whole thing. This lash up is based on the article "The Novice Q5'er" by Don Stoner, W6TNS, that appeared in CQ Magazine in January 1956. This was good news, because it meant that I now have excellent documentation on about 80% of this receiver. Well ... I brought the receiver up very slowly on a variac. At about 90 volts the receiver came to life. At 100 volts it was working like gang busters. I mean this little radio is hot as a pistol! Who knew?! Tuning is smooth as silk. Selectivity that rivals a R-390A -- well okay, maybe not that good. But still pretty decent. Stable as the rock of gibraltar. The only drawback that I can see is the limited band coverage.
At this point the only function that doesn't work well is the volume control. I get audio sufficient to run a pair of headphones, but varying the volume control has little or no impact on the level of AF output.
Here's a run down of the system:
1. Band coverage as a funtion of xtals:
Band Xtal Freq convered
1 3010 3.2 to 3.55
2 3500 3.7 to 4.0
3 4310 4.15 to 4.45
4 5630 5.8 to 6.1
5 6900 7.1 to 7.4
2. Tube lineup
Preselector Chassis
6BA6 and 6BE6
Calibrator Chassis
6BA6
BC-453 Chassis
The 6 stadard tubes
plus two ea 6SN7
Power Supply Chassis
5R4 + 0B2
3. Front Panel Controls
o Preselector Tuning (80M ................. 40M)
o Band ( 1,2,3,4,5)
o Calibrator (on, off)
o RF Gain
o AM - SSB Switch
o Main Tuning (uses a BC-348 knob)
o LSB - USB (varies the bfo freq)
o BFO (on, off)
o AF volume
o headphone jack
There are some significant differences between Stoner's receiver and mine. Among them:
Stoner Mine
Band switching no yes
Slide rule dial no yes
integrated into one panel no yes
6SN7's on BC-453 no yes
BFO control brought to panel no yes
I don't know what the purposes the 6SN7's serve on the BC-453. I'm guessing something to do with AVC that ties into improving SSB reception? One other triode section might be for 1st stage of AF preamp? Those two fuctions could be done with one 6SN7, though. Right? Why would he put another 6SN7 in the BC-453. Dunno; gotta do some research. You guys have any thoughts on this?
Yes, the two 6SN7's sockets were put on the chassis where the dynamotor formerly went.
The way he handled access to the BFO can is also creative. To provide top of chassis access (versus original side of chassis access) to the BFO adjustment cap, he made two cuts into the chassis on either side of the can, then bent the side of the chassis 90 degrees upward. Neat.
The workmanship on this receiver is outstanding. Whoever built this system was someone of your caliber: superior skills, expertise and knowledge. I can imagine that it took several months to design, fabricate, build, test, and retest and tweak this system. And the result is pretty amazing. After completing it, I bet the builder was damn proud of how well this receiver performs!
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