I've never heard any Triton or Omni A, D, or C owner complain about
performance. Though by my circuit analysis, I think the Corsair II is a
superior receiver with better dynamic range, especially for handling
strong adjacent frequency signals. That's because it uses a transformer
feed back circuit with RF power type bipolar transistors for the RF and
first IF stage and double balanced diode ring mixers that have good
strong signal characteristics. I think the IF gain of the Triton/Omni C
is a little on the low side, but that gives it a cleaner sound. Having
only one mixer can give it a cleaner sound, but it may not quite hear
the weakest 10m signal. I doubt there's a detectable difference on 75
meters or 80 meters in weak signal detection because antenna noise can
be so much greater than RF stage noise. But strong signal handling
capability helps get a good signal to noise after the detector because
that way neither adjacent channel signals nor strong static overload the
radio to gain more emphasis than their relative power deserves. Not
having a second RF mixer (other than the mixer to audio, called a
product detector) the RF section gain can be lower in the Triton. Low IF
gain may not be all bad, as that can reduce the noise on the opposite
side band contributed at the product detector. Then an audio lowpass
filter and quiet audio stages can make up for the low IF gain... There
are a lot of trade offs.
The Corsair II has double conversion with IF's at 9 and 6.3 MHz. More
oscillators means more birdies. With 8 poles of filter in each IF
there's pretty good skirt rejection and the pass band tuning allows
shift the edges independently so the effective bandwidth can be narrowed
to almost nothing. And 8 poles of filter causes more delay to make AVC
without pops harder to accomplish.
Some days I'd like to compare a Triton and Corsair II side by side under
various conditions both for weak signals on 10m and on 80 or 160m and
alongside strong signals. I suspect that the Triton will hear as well
on 80 as the Corsair II but will be bothered more by strong close
frequency signals due to active devices not as capable of handling big
signals and fewer filter poles. I suspect that the Triton may not hear
as well on 10m due to a bit lower overall gain, BUT I'M not sure of
that.
I'd kind of like a receiver to use the Corsair II RF stage, mixer, first
IF stage and 9 MHz filter, then have some gain and have another SSB
filter before the product defector so it sees only IF noise at
frequencies that have passed through the first filter. I'd like there to
be a bandpass filter between the RF stage and mixer for the same reason,
and that's lacking in the Corsair II. Its probably in the Triton because
of the impedances needed for the double gate MOSFETs. The I'd like that
receiver to have a good low noise (perhaps passive) low pass filter
cutting off to match the SSB receive filter, then another at the speaker
(again passive) to reduce the high frequency noises contributed by the
audio stages. All those things help signal to noise without affecting
the signal. I know the speaker filter helps and I think the others can
help by reducing the RF stage and IF stage gain required to develop
system noise figure and the best possible signal to noise at the
speaker. My Yaesu VHF/UHF multiband multimodes fail miserably at both of
those compounded by lots of intermod from local oscillator phase
noise...
I don't think without comparing a Triton and a Corsair II side by side
with a quick antenna switch for an extended period of time that one will
ever come to a sure conclusion of which is better for all situations. I
suspect each will excel on some occasions and conditions. I know that
was the case when I compared a Corsair II, to an Omni V, and a Cubic 102
one Saturday when 10m was barely open for DX. One of the features of the
Cubic is a separate front panel IF gain control which the owners tell me
does wonders in improving signal to noise ratio at the detector. One
other feature is continuously variable bandwidth which though
uncalibrated in the Corsair II is what the bandpass tuning control
effective accomplishes.
73, Jerry, K0CQ
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