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[Amps] Cleaning and lubrication of ribbon variable coil

Subject: [Amps] Cleaning and lubrication of ribbon variable coil
From: "jim.thom" <>
Date: Sun, 14 Aug 2022 14:49:56 -0700
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<I would think that dielectric grease is the last thing you want to use.
<You don't want a dielectric here?

<73, Jim W7RY

On both my RI-40 (tapered pitch)  and also RI-50..both use 3/8" edge wound
ribbon coils.   There is a pair of gold contacts on EACH side, that pinch
the SIDES of the ribbon.   Dielectric grease was installed, right from the
factory on both sides of the ribbon.   In the middle is the 3/4"  square,
silver plated bar stock, with contacts on all 4 x sides.   End plates have
4 x huge contacts riding on the large diam disc.  Dielectric grease used
everywhere, but everywhere has multiple contacts, loads of pressure, and
grease is used sparingly... ultra thin layer.   What else that works is
..'conducto lube', sold by the 'cool amp' company in Ore.   'conducto lube
is just pure ground up silver powder in castor oil.

On a side note, the ARRL handbook has the wiring for roller coils done
incorrectly since day1.  The correct method is to enter the coil at the
back end...and also exit the back end.  Permanent short is at the front
end.   Done that way,  the total path is minimal on upper HF bands......and
longer path on lower bands.  After existing the back end of the roller
coil, then it's off to the load cap.

The ARRL method has it backwards, resulting in extreme lengths  being used
 ( entire 'bar' )  when on upper HF....and also exiting the front end of
...'the bar' ..then over to the load cap.  If a vac load cap is used, using
the ARRL method, results in an excessive long lead from front end of coil
to  back end (hot end) of the vac load cap.

Jim  VE7RF
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