Awhile back I requested info on this "collectible" late 1970's 40
channel CB.
Except for photos and some microphone pin out information the Internet
was mostly a black hole for details on this rig.

After a couple of days I came across Ken's Electronics web site.
They have a cross reference of SAM's photofacts for CB that suggests
looking for "twins" of the Fortress
under CB-157 and CB-205.

It appears the Fortress electronics are similar to the Realistic TRC 455
(21-1542)
and the Courier Conqueror 40D. The Rat Shack version seems to have more
info on the web.

I got rid of the PLL noise on the receiver by popping out the PLL
daughter card, opening up the shielding cage, cleaning the shielding
edges with an eraser, replacing the cover and reinstalling the PLL card.

Looks like some one hacked the PLL circuitry for extra channels.
The 3 position delta tune switch provides normal 1-40 channels in the
far right position and 80 extra channels in the
other two positions.

Is there a freq list that matches these extra channels or does it vary
based on the PLL chip?