[TenTec] Argosy "Thump"

[D. Kemp]

I have the complete article run in Ham Radio Magazine
in 1986 about mods for the Argosy.

The mod for the AGC is:

"Improving audio AGC characteristics 
One of my biggest complaints was the popping
characteristic of the Argosy's audio AGC. While most
of the modifications presented so far improve to a
great degree the AGC's reaction to unwanted
out-of-band signals and in-band background noise, a
simple additional modification will virtually
eliminate popping. This change consists of replacing
C12 on the i-f/af board 80785 with a 22-uF, 35VDC
tantalum capacitor, which exhibits a favorable
charging curve that cancels out the annoying "pop," at
the same time providing a more suitable response time
for the AGC. With this capacitor in place, the attack
and release times were measured at 20 milliseconds and
2 seconds, respectively. This constitutes an almost
perfect compromise between CW and SSB. (This
modification can be incorporated when the other
changes are being made to the same board.) When
installing the tantalum capacitor, be sure to observe
polarity. After this change, popping was almost
completely eliminated with only a hint of it left on
signals exceeding 40 dB over S9 in level, and with all
filters(including narrow af) inserted. In order to
completely eliminate the popping, the addition of the
rf gain control is required RF gain control"

I don't remember where I got it, but probably Googled
it. I can send it to anyone if you want it. It has
lots of mods.


73,

Don, NN8B