There was (is?) also the p/n221 filter. It is centered at 9.000500 and
is 250 hz BW. Using this filter results in a CW offset of 500 hz instead
of the "industry standard" 750 hz offset. The lower offset is much
easier on the ears and creates less fatigue from operating long hours in
contests, etc. This filter has 14 dB loss and I'm wondering if this is
useful as a roofing filter in the Orion?
I thought there was a corresponding 6 mhz, 250 hz filter to match the
low offset 221 filter and I thought I had it in my OMNI VI+, but I can't
find the invoice where I bought it. I found the invoice for all my other
filters. I do have a p/n 282, 6 mhz, 250hz BW filter in my VI+,
according to my records. Perhaps this works with the low offset 9 mhz
filter without a need for another filter at 6Mhz.
Dave, K4TO
Zivney, Terry L. wrote:
Barry N1EU said:
Correct me if I'm wrong, but Bill is ordering filters
with a center frequency of 9.001500, which isn't what
the Omni VI is looking for.
Correctomundo, Barry! But, 9.001500 isn't correct for
the Orion, either. The 9.001500 "standard" for
wider TenTec filters is derived from the idea of
0-300 stop band
300-2700 pass band (i.e., 2400Hz bandwidth)
2700-3000 stop band
and the symmetry of switching sidebands by moving
the BFO frequency 3 kHz. If you get a center frequency
of 9.001500 with a narrow bandwidth, 400, 500 or 600 HZ,
you are assuming you want a CW tone of 1500Hz with
a BFO of 9 MHz. The correct center frequency for
the narrow filter is 9.000750, which results in a
default CW pitch of 750 Hz, +/- the adjustment.
In summary, I believe a better choice for a special
order frequency is 9.000750, which would accomdate
both Orion and OMNI VI users.
Thanks for pointing out the offset problem.
Terry ZIvney, N4TZ/9
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|