Jim,
Your problem may be that you are centering the filters. There was a
post by Lyle Johnson a while back which explained that the filters are
not operated at their center, but are used closer to the slope than
center to take advantage of the better rejection provided.
I don't recall the exact circumstances, so you might want to look for
that post in the archives.
73,
Don W3FPR
Jim Miller wrote:
I spent a few minutes today checking the filter gain balance on K3
1210. I fed in a 1uv signal from my XG2 and qualitatively measured the
audio out when switching (XFIL) between filters. I started by finding
the XG2 signal and zero beating it using the CWT/SPOT features and
then switched between filters.
I have an 8 pole set as follows: FL2-2.8, FL3-1K, FL4-400, FL5-250.
I have gains as follows: FL2-0db, FL3-0db, FL4-3db, FL5-8db.
The audio is good with these settings except for FL5 which even though
maxed out has a very noticeably lower output. By fiddling with the FL4
setting and doing comparisons it appears that FL5 could use another
3db to bring the output up to equal that of the other filters.
Just to make sure I was in the center of the 250hz filter I tuned
around with the FINE setting and moving around made no improvements in
the output only the expected decrease as I moved outside the filter
BW.
Is there any remedy for this?
Should I send my 250hz/8pole back for replacement?
tia
jim ab3cv
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