[Milsurplus] ARC-2

[Hue Miller]

An idea suggested for the ARC-2 selectivity challenge was to make one IF
stage regenerative via grid-plate capacitor. Maybe, i'm thinking, this ideawas advanced in Roy Pafenberg's  ( sp ? ) booklet, something like,"ARC-2, A Modern Transceiver in a WWII Package".  I wonder how well thisidea works out in reality. Regenerative IF stages i have never liked; theyare simply too peaky and difficult to gain-control. But an added Q-multcircuit, a 2-terminal one, is an idea i want eventually to try.Talking with Walt Hutchens years ago about the ARR-15, i mentioned regenerative IF stages for this receiver, but he said he felt the trackingof the variable IFs was not true enuff for this to work. However, thinkingabout it, i believe tracking not that big an issue, if you're not absolutely tied to the idea of perfectly accurate dial frequency readout. After all,you can compensate via the tuning knob.  Now on the ARC-2, the problemmay seem a little more challenging, in that you face tracking problems both with the osc and the simultaneously variable. However, i don't think that's a game stopper: as long as the IF tracking is going off in thesame direction, i.e. not jumping up and down, i think you can still just use the tuning knob to find your signal, depending less on the actual frequency readout. So i think the regen IF, or better, the Q-mult, would be applicable here too. BTW, this 2-terminal Q-multidea also appears in one of RSGB Pat Hawker books, "Amateur RadioTechniques" i think it is, where it is applied to an IF stage and it usesa dual triode like 12AT7. I emphasize that this Q-mult, like a Franklinoscillator, uses the tuned circuit in the radio as its tuned circuit, and is a 2-terminal device, so it's easy to apply, and to DC controlremotely.Now to the ARC-2 design. Who has some thoughts about why so many RF stages to this thing? And why so many RF tuned circuitscompared to the IF tuned circuits, which really aren't that many -as seen in the -b r o a d - selectivity specs.Also - Pafenberg's booklet - i don't have - what did his conversionconsist of ?-Hue Miller