As promised a while ago, I have written this look at the Omni VI is from
the perspective of a Corsair II user (and fan!) for hams on the TenTec
reflector to read. This purely subjective information comes from using
my new Omni VI for a grand total of five weeks after having a Corsair II
in constant use for Dxing, contesting, and general all around ham radio
for over 3 years. I should add that I operate CW about 99% of the time.
Similarities:
1. Both made by TenTec; this fact speaks for itself and conveys the idea
of quality construction and legendary service.
2. The two rigs use the same filters in the 6.3MHz IF; e.g., you can use
your Corsair II filters in the Omni VI. I am also using my TenTec 961
power supply that came with the Corsair II; it works fine.
3. The two rigs "sound" alike when listening to CW; this may be a
function of using the same IF filters and is hard for me to define, but
that=92s the only way I know how to say it. I should add that I mostly use
the 500Hz filter for CW.
4. Both rigs have internal keyers that I can=92t comment on; I use an
external keyer.
Differences I have noticed:
1. When you are in the CW mode, the CW sidetone is always on the "upper"
side of the zero beat frequency on the Omni VI; on the Corsair II it is
on the upper side on 30 Meters and below and on the lower side above 30
Meters.
2. The noise blanker on the Omni VI works. I never saw any effect of the
Corsair II=92s noise blanker on any interference I experienced. I don=92t
think it was just my rig either; I have two friends with Corsair II=92s
who have had similar experiences.
3. The CW sidetone frequency and the transmit offset from the receiving
frequency are identical on the Omni VI and can be changed, but if your
transmit offset gets far from 700 Hz the CW bandpass filters won=92t work
right because they are centered on 700 Hz (you can compensate with the
passband tuning, though). On the Corsair II the transmit offset is fixed
and you can adjust the=20sidetone frequency by itself. The sidetone
quality on the Omni VI is much nicer and easier on the ears.
4. The top-mounted speaker and/or better audio output make the Omni VI
sound better than the Corsair II on SSB and CW; the audio seems clearer
and stronger. I almost always used the speaker in the 961 power supply
with the Corsair II; now the power supply is tucked away out of sight.
5. The passband tuning in the Omni VI just works better than the one on
the Corsair II. It seems to cut out interfering signals cleanly with a
minimum of distortion both on CW and SSB.
Operating Impressions:
When I first sat down in front of the Omni VI I noticed two things: the
frequency display is larger and reads to the 0.01 KHz, and the tuning
knob feels smoother and, well, just nicer. The tuning rate on the Omni
VI can be set from 0.85 to 5.12 KHz per revolution, but the fastest
rate, 5.1 KHz per revolution, is much slower than the Corsair II=92s 17
KHz per revolution. After a short adjustment period for my fingers, I am
now used to and like the slower tuning rate on the Omni VI better.
The Omni VI makes use of some coaxial control knobs rather than having
all single function knobs like the Corsair II. However, usually only one
of the coaxial knobs=92 functions is used frequently, and the other is
"set and forget". For example, AF and RF gain are ganged, as are drive
and mic gain. In case you didn=92t guess, I=92m not a fan of coaxial knobs=
=85
The receiver in the Omni VI is HOT! At first I thought that the Corsair
II was quieter, but then I realized that the Omni VI=92s receiver is more
sensitive and that I was hearing more signal, too. The AF gain control
seems more sensitive in the Omni VI than in the Corsair II; with head
phones on the control goes from very quiet to very loud in only about 90
degrees of rotation. It would be nicer to have a more gradual, linear
"volume control". I use both transceivers with their RF gains set from
about the 1 to 3 o=92clock position under normal conditions. I rarely have
the RF gain "cranked up" all the way.
The Omni VI is definitely more selective than the Corsair II for CW
contest-type operating with lots of adjacent strong signals - even
without using the 500 Hz filter in the 9 MHz IF. With the 500 Hz, 9 MHz
filter, the performance is awesome; you can work very close to strong
signals and not even be bothered by interference. I am using exactly the
same 6.3 MHz filters in my Omni VI that I had in my Corsair II. I have
experienced absolutely no ringing or signal deterioration using the 500
Hz or 250 Hz filters either with or without the addition of the 9 MHz
filter.
Things I miss:
1. The big one - being able to listen to two frequencies at once and
vary their relative volume like I can with the Corsair II and its
external VFO. But with the A/B split on the Omni VI you can alternately
listen to two frequencies, even on different bands, just by holding and
releasing the REV button, very nice.
2. With the Corsair II, I used its QSK output jack to key my venerable
Drake L-4B amplifier through an external QSK switching box that I built
using Jennings vacuum relays. The Omni VI does not have a direct QSK
output analogous to the Corsair II=92s, so I have to use the T/R relay
output and run my amp essentially non-QSK. There may be a possibility to
use the QSK out and enable jacks on the Omni VI, which are designed for
use with the TenTec amps to drive my QSK box; I=92m looking into that
possibility.
Omni VI features I now can=92t live without:
1. Moving around the bands with direct frequency entry and switching
from band to band and always returning to the same frequency-filter-mode
on a band.
2. Having a computer interface to the rig so that my contesting and
logging programs can automatically control the rig=92s frequency and
vice-versa.
3. The additional selectivity of that 500Hz filter in the 9MHz IF.
4. The DSP notch filter is "magic" on SSB. You just hit the button an
tuner-uppers and heterodynes simply vanish.
Regrets:
My only regret is that I waited so long to get the Omni VI!!
I hope that some of you find all of this interesting and informative.
Hope to see you in the NA QSO party contest tomorrow!
73 es Happy New Year - John, W4AU (ex-W3GOI)
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