The 400Hz filter on my Main RX is an Elecraft (by INRAD) 8-pole filter
in a Faraday cage and no offset.
The 400Hz filter I just received for my SubRX is an Elecraft (by
Vibroplex?) that is a 6-pole filter with no Farady cage AND it has a
-0.71 kHz offset.
I called support when I saw the obvious differences, and they said,
"Don't worry about it. Enter the SubRX offset exactly as on the crystal
(no averaging with the [supposed] 0.00 offset on the 8-pole filter), and
let the new Synthesizers do the heavy lifting." or words to that effect.
I hear what was said, and I don't want to come off like I don't trust
what I was told.... But something simply is not sitting right with me
on this.... a 6-pole "matched" with an 8-pole? No offset averaging?
What about the difference in the skirts between a 6-pole and an
8-pole.... Aren't the cutoffs and cutoff rates different? I realize
that things change, and that perhaps the instructions for averaging the
offsets is not applicable here... (though I don't yet understand why)
Can someone clear this up for me so even I can understand it.
Seems to me that I either need to get a matching INRAD-made 8-pole, or
buy another of these new parts and try to get it matched.
Want to move on this, because IF I am going to have a hope in getting a
"matching" 6-pole (new stock) 400 Hz filter, I need to try and do so
from within the same batch that the one I just bought came from.
The prospect of finding an "by INRAD" 8-pole available on the market
seems much less likely...
Obviously, I am operating on a number of assumptions here... which is
why I am asking...
73
______________________
Clay Autery, KY5G
(318) 518-1389
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