[ARC5] [Milsurplus] AN/ARC-2 manual

[Hubert Miller]

Here attached are scans related to the topic, improving the selectivity of variable IF radios, Collins. 
Also the book cover where these came from. 
A HIGHLY recommended by me book, if you're interested in SSB generation methods and filers and VFOs, 
based mostly on vac tube technology. Was written about at the turning point, 1958. 

I first was turned on to 'single terminal radio freq oscillators' by paragraphs in Pat Hawkers RSGB book,
'Amateur Radio Techniques'. Another real classic. Described a 12AU7 ( dual triode device ) used in a 
no - tuned circuit Q multiplier, receiver add - on. Absolutely forget the regenerative IF stage idea; a bad 
idea unless you are living in the 1930s and it's a new kink. It just does not work well, and i won't go into 
the fault reasons again here. Roy Paffenberg's ( sp ? ) book, 'ARC-2 A Modern Transceiver in WW2 Package'
( my rendering of title by memory, which may not be absolutely correct ), i think has you add regeneration
to an IF stage. Do not waste your time with this.

So i was thinking the Franklin osc circuit, with a gain control in a cathode, or actually better, MOSFET source, 
with similarly low coupling caps, might do for an outboard selectivity boost. Like per the Pat Hawker book 
example. In the ARC-2, the IF is continuously variable, which is really a devilish perverted idea, but it worked
for the few years this rig was in service. Oh, and, an audio selectivity device won't help you out listening to 
SWBC or ham AM or SSB. It did occur to me that if the ARC-2 IF tracking was not perfect, maybe you would 
find yourself tuning downward as the tuning knob increases. Both the HFO and the IF continuously climb 
thru the tuning range. Maybe that wouldn't even matter. Maybe it will not happen. The IF tracking may be
a little less linear, but it does proceed steadily thru the band. I have not done the bonehead math to look at 
any possibilities. Anyway, there it is. My current thinking is to move from OR back to WA state and that's
going to be my focus for a while, so i cannot experiment with these ideas for maybe 3 years yet. So maybe 
you can run with it, or just add your comments to the group.  The Franklin Q Multiplier needs at least one 
more control. You don't want to add something to the front panel. The ARC-2 has maybe a fuse holder you
could use, with a small plain knob; no one but a pro could maybe tell it wasn't original. The ARR-15 has a 
screwdriver gain control in the lower right. 
I think that's all i have to say.

Oh - unrelated asside: I will Monday gather the RUGF box and connector i promised and pack them up.
-Hue Miller 





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