Topband: Stainless Steel for coil taps.

[Richard (Rick) Karlquist]

On 11/16/2020 7:58 AM, Wes wrote:
> Nickel is not OK.
> 
> I could tell a war story about gold plating over a nickel barrier where 
> the plating shop skimped on the gold.
> 
> Wes  N7WS
> 
> On 11/16/2020 4:05 AM, Rob Atkinson wrote:
   EF Johnson and perhaps others used steel nuts and
>> bolts that were plated with nickel.  

I have a war story to tell:

HP used to have pretty gold plated PC boards, which of
course had the obligatory nickel barrier.  I was the
project manager for the HP5334B frequency counter,
which was a cost lowered version of the 5334A model
that used gold plated boards.  By the time of the
B model, HP was doing all new products in "Solder Mask
Over Bare Copper" (aka SMOBC).  No gold or nickel.
I had the front end section of the 5334A PC board
leveraged to use in the 5334B.  Exact same schematic
and layout.  Only difference was the SMOBC process.
Upon turn on of the first SMOBC board, I was not
especially surprised to find out that the front
end circuits now oscillated because the lossy PC
board containing nickel was replaced with just copper.
I had to add back in some loss with damping resistors
to make it stable.

Rick N6RK