[R-390] Some progress

[Dan Merz]

Scott,   stainless steel is a very poor electrical conductor and heat
conductor,  on a scale of  1 to 10 for metals,  its probably about as bad as
a metal gets.  If you want something to get hot,  put a strip of stainless
steel as a heat barrier between it and the heat sink.  The AK 55 had an
ordinary low carbon steel chassis with a good finish,  probably enhanced by
their drawing and cleanup procedures.  I've seen examples that are badly
rusted and pitted with time.   Mine is in original condition with a dull,
satin look that could be made bright with some aggressive cleaning.  And it
is a true marvel of metal working and fabrication,  like the 390a very
pleasing to see.   Offhand,  I can't think of a radio that used stainless
steel for components or the chassis;  it would have been expensive and
difficult to form compared to ordinary steel and aluminum,  and has poorer
electrical and heat properties.  Dan.

polaraligned wrote:

> > attractive for wiring in the first place.  Too bad it forms a coherent
> > non-conducting oxide so easily - bad for junction contact
>
> > Dan.
> >
>
> I am suprised they did not use thin stainless for a "no holds barred"
> receiver.  I'll bet the aluminum has caused a lot of strange problems
> in the past such as ground loops, etc because of the formation of
> aluminum oxide.  That is why I treated all my grounds.
> The best built radio I ever worked on was a Atwater Kent 55c which was
> built in 1929.  It had a stainless chassis and was made like
> a work of art.  The chassis cleaned up to almost a chrome plate look.
> Too bad the radio is not a performer....It is just a TRF unit in the days
> before commercial heterodyne radios.
>
> Scott
>
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