[Hallicrafters] SX-25 coil loops etc

[Mark Shaum]

----- Original Message ----- 
From: "Jim Liles" <james.liles at comcast.net>

To add padding on band 4.  Use a grid dipper and a moveable shorted turn
or added half loop to the connection and spend about an hour with power
off aligning from end to end.

Jim,

Nice idea!  Shades of the HRO coil sets where I've spent much quality
time pushing a half turn of wire within the coil cans to and fro during
alignment, hoping the wire wouldn't break!

I've noticed the same lack of tracking amongst the RF coils in my SX-25
on band 4 as well.  While I find the existing sensitivity even on 10
meters sufficient, adding a movable shorted turn is an interesting and
fairly easy to accomplish method of reducing inductance.   It also
reduces Q but not significantly as the shorted turn isn't in series with
the actual inductor.

Makes me want to return to my "ultimate" All-American 5 BCB and SW
homebrew, now with movable half loops in each inductor in addition to
CAD designed tuning capacitor rotor plate shaping and padding
capacitances worked out via a Fortran program for the do-all and end-all
of dial tracking and linear tuning.  Fortran? Well, ya gotta be vintage
with the software too, right?

73! - Mark K9TR