INRAD #352 612Hz filter built by me and tested by Rob Sherwood. It is first
class and meets specs. $56.00 shipped in the US.
This filter is to be placed in the Orion's 1000 Hz filter position as the
insertion loss is equivalent as is the input impedence (200 ohms). As a
result there are no gain compression issues and you will improve your DR
over the stock 1000 Hz filter at even closer spacings. You should make the
center frequency 9.001500 and everything will center properly. Since there
is no center frequency compensation for the 1000 Hz filter, you might need
to slightly tweek the PBT control if you are so inclined. I never did.
The 600 Hz filter has a BW of ~900 Hz at 20 dB down versus the stock 1000 Hz
filter which is ~1070 Hz at 6 dB down, so there should be some noticeable
improvement in dynamic range performance at very close spacings.
73,
Charlie, W0YG..>>
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