Quoting Steve Ellington/N4LQ:
(snip)
The Triton through the Omni C were single conversion rigs with a 9mhz IF
stage. Addition of 17 meters, pressure from imports and quest for
greater
selectivity prompted TenTec to incorporate an additional mixer and I.F.
amplifier at 6.3mhz. Along with this came the handy PBT tuning and
greater
image rejection but the down side was greatly increased noise. The
basic
Corsair design continued in Omnis 5, 6 and Paragon using the same I.F.
components. A tone control was added to the Omni V/Paragon to give some
apparant relief from racket then low pass dsp filtering was added to the
Omni VI to tame the beast.
This is why I believe the Omni C is the best compromise. It's got the
single
conversion design but has the added benfit of narrow xtal filter
selection
plus switchable audio filters all within the agc loop plus it has 160m
and
warc bands. Just don't bother using 17meters.
(snip)
Unquote
I agree with the above but have been confused about model nomenclature.
What is the Omni C??
As far as I know, Ten-Tec introduced the Omni-A (analog) and the
Omni-D (digital) in 1979. They followed this with the Omni-D, series
B then the Omni-D, series C (or so I thought). Did they drop the
Omni-D name and go to the Omni C (really meaning the version C)??
If so, the Omni-C in effect, was made after the Omni-D - confusing....
The original Omni-A&D, had only the three skirt audio filter.
The Omni-D, series B, dropped the squelch and had a multifunction
xtal/audio filter selector switch. It could transmit on 30Mtrs with
component additions (as I've done with mine) and had one other "aux"
position on the bandswitch. The Omni-D, series C separated the filter
switch. It used one for the audio and another for the xtal filtering,
making selections of each more independant. It also came with all
WARC bands including the 18MHZ band. Despite those who say that the
earlier Omni's can't be modified for 18MHZ, Ten-Tec apparently
did ship the C versions with 18MHZ enabled. Guess no one checked their
specs too closely??
I've got various pieces of sales literature showing the evolution of the
Omni series - interesting.
I recently sold my Triton IV and rather regret it. It seemed quieter,
better AGC action, and narrower audio filter response than does my
Omni-D, series B. I've added the 500HZ xtal filter to the Omni which
did improve things.
I also noticed a comparision to a Swan (Cubic) Astro 102BX.
Although a much different design, I've got the Cubic Astro 150A
which is a totally synthesized rig.
It compares well with the Ten-Tecs on CW with smooth QSK, good filtering
etc.
The surprising thing is its low phase noise. They did this by using very
tight
loops with the side effect of long lock up times (it takes up to 15
seconds
to lock up after changing bands).
Anyone else have the SYNTHESIZED Swan/Cubic Astro 150 for comparison
purposes?
73,
Doug/WA1TUT
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