Anyone do the 8 pole filter into the stock slot 515 trick? I
just did it last night (2.4 filter), easy, no big deal, but there is
significant blowby (same as for the stock 4 pole filter) and
I wonder if anyone else has tried to cure it.
Has anyone put the 8 pole filter in the receive line AFTER
the stock 4 pole filter per the QST / QRP Quarterly articles
and found that the blowby is reduced? Maybe it is an
artifact of the physical design of the board where the stock
filter goes?
I plan to slide a piece of copper under the filter and over the
board and make that a nice ground plane to see if that helps.
Next, I may put the stock filter back in and place the 8 pole
filter in the receive line to see if that does it, though I
don't want 12 poles, may make the audio rather restrictive
for me. Anyone know about this stuff?
My next move is to put in the 500 Hz crystal filter for CW,
that would necessarily go in the line after the standard
filter. Maybe I will just put that thing in and see if there
is any blowby. My Kenwood 130V has similar blowby with
the CW filter but not the SSB filtering, so I figure it is
with the diode switching, but no diode switching in the 515.
I will use relays!
Clark
WA3JPG
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