[Collins] R388 Product detector mods

[Philip Neidlinger]

Well, I got the product detector mod done in accordance with the 68 CQ
article. It works. However, there are a couple of issues.

1. The volume of the radio drops when you switch over to the bfo,
approximately 50%. I assume this may be due to the voltage divider to
ground 1.2K in conjunction with the 5 pf cap. The volume with the bfo on
is entirely inadequate. I assume if we did a direct feed with the 5 pf
cap and deleted the resistor this might improve. Am I on the right
track?

2. Volume with the AVC off is better than with it on.=20

3. When the af gain is advanced much past 8, the rig goes into a low
freq audio oscillation.

Otherwise the mod performs as advertised. I am new to tube rigs and
point to point wiring. These 40 year old eyes had trouble with that
soldering.

Philip
KA4KOE