[Collins] Re: 75S-1 more adventures.

[kiyoinc at attglobal.net]

** Reply to note from Zook, docGer, Ian, Jim, Deric Tue, 15 Jun
2004 04:01:35 -0400 (EDT)

Soldering - I have a 100 Weller 8100B that my dad bought for me
in 1962 so I could build my Knightkit R-55.  The R-55 is still
in my mom's house. 

In following the Knightkit manual, I wraped the wires around
the terminal strips and then soldered them using lots of heat
and just enough solder to get a tight to the wire look. 

Over the years, I got Ungar and Weller pencils of different 
wattages and tip sizes.  The numbers got smaller each decade. 

None of the pencils seems big enough for the 75S-1 main cap but
two folk have suggested cutting the wires at the capacitor so
that is what I will do.  That is, after drawing the hookup very
carefully.

This 75S-1 has the 500 cycle mechanical filter in it.  It
sounds nice on the 312B-3 and my modified (disconnected the
tweeter) Radio Shack Minimus-7.

When I switch from USB to CW, the pitch of a carrier shifts
about 400 cycles. This is measured on the Tektronix scope.  I
found this quote in the manual, 

"When the accessory 500-cps filter is used, but the matching
bfo crystal is not used, the CW beat note will be 1350 cps with
the signal cen centered in the passband.  When both the
accessory 500-cps filter and its matching bfo crystal are used,
the CW beat note is approximately 800 cps with the signal
centered in the filter passband, and zero beat cannot be
heard."

page 3, 75S-1, Section II Operation, right hand column.



When I connect the Tektronix to the 312B-3, the audio level
drops.

I don't know why this is.  

de ah6gi/4.