Joe writes about standard vs. wider SSB filters, and raises some
good points. I can address them a bit, from my own personal
perspective.
I find the tradeoff of smoother sounding SSB from 2.7 filters
(such as I have in my Kenwood TS 440, they came from an 830)
very worthwhile. The narrower sound from a pair of 2.4 filters
is just so restrictive that my ears seem to grumble. Now, the
difference in QRM from 2.7 to 2.4 is not a big deal to my ears,
and I can usually get the same effect by use of the PBT or IF
shift. I HAVE seen a real difference in a 2.1 filters from
INRAD, the skirts plus the bandwidth do cut the side crud from
SSB signals, but there is not much left of the sound. This is
OK for mobile and quick communications, in fact, it is great for
that. However, for armchair ragchewing on SSB (I do this a lot
more lately) it is awful. The wider sounding filters are for
me there.
Since the OMNI VI allows me a myriad of filters, I would prefer
a wider pair of filters stock, then use the PBT and an optional
filter IF and WHEN I want a narrower sound. My preference. I
have this choice in my Kenwood rig, but not in my Ten Tec at
the present point. It just means my OMNI VI is more of my CW
rig and the Kenwood remains as the SSB ragchewing machine
unless I take it mobile or portable (the main reason I have
that rig, auto tuner and stuff, you know).
On the comment about the narrow audio bandwidth in the OMNI VI,
I have found the position of the PBT problematic, even when
aligned properly per instructions. The Ten Tec (Network
Sciences) filters are not quite symmetric and you may notice
a big difference from LSB to USB. I have used my "ears" to
adjust the carrier oscillators to get LSB and USB to be
similar (as far as my ears could tell....) and the PBT
centered.
Can you "correct" the narrow sound problem with the PBT at
all? If not, I suspect your model 220 main IF filter has a
problem. I have had this happen to me. Not a big deal to
replace. If you were nearby, I could loan you a 220 to plug
in and see. I suspect it could also be the 6.3 MHz IF
2.4 filter, too, you might check that. Have another OMNI in
your area you can swap filters with? Good luck. Let us know
what you find. Since I have been inside my OMNI a number of
times with the BFO, PBT and stuff, I am very interested in
any knowledge about these things.
Clark
WA3JPG
--
FAQ on WWW: http://www.contesting.com/tentecfaq.htm
Submissions: tentec@contesting.com
Administrative requests: tentec-REQUEST@contesting.com
Problems: owner-tentec@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|