The 13cm PA notes are interesting and remind me of
a question I had from when I put the W6PQL 23cm
Here's my confusion: The source of the device is
connected to the flange. The matching circuit that is
a transmission line is made from PCB, with the
groundplane and the top conductor forming the
transmission line transformer.
My understanding would be that the groundplane end
of that transmission line has to terminate at the
source, with minimal inductance, just as the "inner"
has to terminate on the gate connection.
The SP5MXU documents talk about the 13cm boards
oscillating if the connection between the groundplane
and the source is not sufficiently good or close
enough. This sounds reasonable and as I would expect,
a good grund contact is important.
My confusion is that W6PQL mentions getting the
board height just right for the devices, if necessary,
adding thin sheets of paper between the board and the
copper spreader ... obviously in this arrangement, the
source to groundplane contact is somewhat convoluted
and distant ... yet, apparently many have been built
like this with no ill effects.
Surely that cannot be right? Did I miss something?
Is there some "well, the groundplane and the spreader
are basically in the same path it doesnt have to be
actually electrically in contact" thing that I missed?
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