[Collins] 51J parts

[Dr. Gerald N. Johnson]

On Wed, 2008-04-30 at 10:51 -0700, Lawrence Mayhew wrote:
> While we are on the subject of the L-105 coil for the 51J series, may I ask
> about the "tuning slugs"? Somewhere I got the idea that the slugs in the
> tuning rack were not all the same permeability. I can't confirm it in the
> technical literature. Anyone have an experienced opinion? 
> Regards,..........Larry in Seattle
> 
I think they are different permeability. Higher for IF and LF, lower for
higher frequency front ends. Notice that besides different sizes, they
are different colors.

There's not enough data out that I have for the 51J family to confirm
that, but I have a full set of R390A drawings on CD-ROM and I have
looked up the slugs and they do have different permeabilities (mostly
powdered iron variations) for different applications. I know those I've
picked up surplus have a range of material colors, but unfortunately few
are identified with part numbers so finding them good homes is very
difficult.

I wouldn't be surprised to find that each core permeability is assigned
a different physical size (diameter or length) in a radio just to make
it easier for manufacturing and service depots to tell the slugs apart.

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer