[SignalOne] Tuning Tool

[jerry]

Hello All,

    I now have what I hope will be the ideal tuning tool for the trimmer 
caps for the broadband plate tuning on my CX7A.

First, I figured out the exact size of wrench needed from my collection 
of ignition wrenches.  I think it was
7/64ths, but don't remember at the moment.  I found a socket of the 
appropriate size.  Its outer diameter was
too big to fit on the caps - because of the mounting screws sticking out 
on each side.

So I chucked the socket in my Sherline lathe and turned the outside 
diameter of the tip down till it would fit.
Then I parted off about 3/8 inches of the socket.  Then made a handle 
out of a piece of hacksaw blade, grinding it
down to the reasonable width.

   Then I needed to stick the handle to the "bit".  How to do it?  First 
I tried spot welding it.  Nah, no matter
how high I turned up the joules, the spot welds ( powered by a car 
battery ) would not penetrate adequately.   Then I
tried MIG welding it - no go on that either.  My MIG welder just doesn't 
do down that far.

   OK, let's try radio solder.  Got out the 350W Weller Dual-post.  
Sanded off the mating surfaces nice & clean and tinned
them.  Then laid the bit on the handle and started heating.  It took a 
while, but it did solder.  Now, radio solder isn't
very strong, but this really doesn't need to be very strong.  It only 
needs to turn the caps without breaking.

   That done, I covered the handle with shrink tubing.

   It works pretty well.  Would have been better if I had used a 12-point 
socket instead of a 6-point, but sockets that
small are generally always 6-point.

   Got all the broadbands adjusted - 80M thru 28Mhz.  Didn't do 160 
because you have to take off the cover, and I don't have
an antenna for 160 anyway.  And I didn't do 29MHz...because that band 
doesn't work.  At all.  Don't know why.  I suspect that
the crystal has gotten tired and doesn't want to oscillate.  I tried 
tweaking trimmer C57, no joy.  Although a bunch of noise
did appear at one setting.  But I don't think it was real.  It wouldn't 
peak with the preselector.  To figure it out for real,
I'm going to have to bring out test equipment.  Maybe later.  I've never 
operated on 29MHz, so it's not high priority.

                  - Jerry, KF6VB