It was written:
>Boy Gene, a scientific comparison would be great, but right now I'd settle
>for someone who says "I used to have the TT filters and now I have the
>INRAD filters and here's my impression". I'm guessing someone already has
>an impression but hasn't posted it to the reflector.
Yes, done that. Impression, awsome in last weedends CQWW CW
test, I have replaced as follows in my fairly new OmniV+:
At the 9 MHz If, I replaced the TT #217, 500 Hz 8-pole with
the INRAD #753, 8-pole 400 Hz filter.
At 6.3 MHz, I replaced the TT #282, 250 Hz, with the
INRAD #751, 8-pole 250 Hz filter; and also
replace the TT #285, 500 Hz with the INRAD,
#700, 8-pole, 400 Hz filter.
Of these changes, the most dramatic during the test was to use
either or both of the INRAD 400 Hz filters along with the TT
NR DSP. Just excellent ability to work "between um". Really
third layer down could be worked within a kHz or closer to
S9 mainland signals as heard out hear in KH6 land. The adjacent
strong signals were just, well gone; not audible!
Now, I must confess that I had not so tested the original
TT filters; just went to the INRADs on the basis of others
comments about their fearures and operational benefits
both in TT rigs and the various rigs of other manufacturers.
So I can't really provide A/B comparisons. Still have the TT
filters, but would be a big hassle to exchange filters back
and forth during actual on the air tests on same signal
Once I learned how to use the two INRAD 400 Hz filters, plus
the TT DS:P in various combinations depending upon the
need, I found little use for the 250 Hz filters. I still have
the TT #221 in the 9MHz IF, 6-pole filter which is optimized
for the audio note tone to be 500Hz. Used the 250's
either alone, or paired up, very little during the 'test.
My experience, yours may vary, hi. I had absolutely no
near by strong signal problems out here. Closest was
KH7R over on Oahu, about 120 miles from my QTH,
across the Kauai channel. So, the 250's might be
very valuable in a mainland area with many contesters/
DX'ers all going after common signals, hi. I could
just stay away from the KH7R frequencies with
their Henry 3K powered signals, hi.
73, Jim, KH7M
On the Garden Island of Kauai
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