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Omni VI vs Corsair II

To: <tentec@contesting.com>
Subject: Omni VI vs Corsair II
From: n4lq@iglou.com (Steve Ellington)
Date: Wed, 17 Jul 96 12:52 EDT
>I have gone back and forth about the pros and cons of the OMNI VI and the
>CORSAIR II.  Does anyone have personal experience with both rigs?  I would
>like insight into the rcvr performance of each.  There is, of course,  a
>$1600 difference between the two.  Thank you for your help.

I've had both Corsairs and the Omni 6. 

1. Corsairs drift a small amount as all the older, pto rigs did. 

2. Corsairs have stiff feeling tuning knobs like all pto rigs.

3. Corsairs had "hang agc" which has a fast attack and slow, sudden release.
   While tuning across a band, a strong signal can activate the agc, make it
   hang and cause you to miss a weak station while continuing tuning.

3. Corsairs agc had a thump on attack especially on strong signals

4. Corsairs tend to have audio or I.F. which is most noticable while using
   the sharp cw filter and wearing headphones.

5. Corsairs have a nice internal keyer. 

6. Corsairs sidetone is adjustable through holes in the bottom.

7. Corsairs have smooth, click free qsk.

8. If you have the external vfo, you can listen to 2 frequencies at once.

9. The matching power supply/speaker is a waste of money. The speaker is 
   too small and the supply causes audio hum if placed near the right side
   of the radio. Use a big speaker and some other brand of supply.

10 Runs cool and no fan is required.

11. Power doesn't fold back but keep an eye on the collector current.


1. Omni 6's are microprocessor driven machines

2. They use a Pll instead of a PTO.

3. The vfo is very stable

4. The BFO drifts about 50hz after transmitting cw for a while.

5. AGC is extreemely smooth and does not hang.

6. Sidetone is adjustable via menu buttons on front panel

7. Some users (me and others) report clicks from the speaker that vary
   with filter selection and passband settings.

8. The first mixer is xtal controlled like the Corsair, unlike kensucom

9. The dial accuracy is not very good by todays standard. Expect 50 to 100
   cycle errors which varies per band. This is due to the xtal mixer stage
   and xtal ageing. Adjusting this is not practical.

10. The microprocessor is notorious for glitches and often requires either
    resetting or power off/on. 

11. The keyer is difficult to use due to a delay in the sidetone which throws
    one's timing off. It too had some glitches. Most folks give up and use
    and external keyer.

12. Qsk is fast but not as fast as the Corsair. Not that it matters but qrq
    cw users report that the top qsk speed on the Omni was limited to a mere
    70wpm. The Omni 5 supposingly would outdo the 6 in this area and so would
    the corsair.

13. A considerable number of mods were made to the 6 over the years. TT doesn't
    seem to have good records of these but they are willing to give them out
    over the phone if you ask a specific question. You may get the wrong answer

14. I've seen many post concerning the so called  SPORT interface giveing 
    folks all kinds of strange problems. 

15. Passband tuning is the best I've seen on any rig.

16. The low pass feature of the dsp takes care of the hiss in the headphones.

17. The low pass in the dsp does not have a sharp cut-off and is ineffective
    in removing qrm.

18. The auto notch dsp feature works but makes ssb sound funny.

19. CW keying produces a very poor note on all Omni 6's I've heard. Some are
    worse than others. I received reports of hard keying with a slight chirp.
    The reason appears to be due to the way the oscillators were designed on
    the tx audio board. Older TT rigs used only one osc. It ran constantly
    and shifted frequency when keyed (vco). The Omni uses 2 vcos. Keying the rig
    starts the oscillator from off to on plus shifts the frequency. The result
    is a sharp rise time plus some chirp. 

20. A keying adjustment is provided however, it only affects the fall time of
    the envelope. 

21. Most cw operators won't say anything about this. (I'm pickey).

22. The volume control is non-linear and bunches up at low volumes.

23. The RF gain control is strange. At mid point it reaches a critical point
    that either allows the agc to work of not. As stations fade, this can be
    distracting and it forced me to keep it turned up to near full level most
    of the time.


I couldn't stand the agc in the Corsair. This is because I operate high speed
cw. Others won't notice anything. 

I didn't like the inaccurate dial, bfo drift (only 50hz). I could live with the
clicky qsk. I could not tolerate the bad cw note. 

I know I'll get some flack on this cw note thing. The factory has heard a lot
of complaints but has no cure. Don't get the impression the cw note is illegal
or totally unbearable. Like I said, most ops won't even notice it. It does
really show up at 35wpm plus though.

Extensive testing has shown that the old Triton 4 had the best keying of any
TenTec! They are pleasant to listen to. The Omni 6 and Paragon 2 both have
very hard keying. I'm not sure how the Paragon developes it's keying but it is
most likely the same as the Omni 6. For several reasons, the Omni 5 has a 
better reputation for cw than the 6. QSK is faster and the cw note is a bit

Is it worth the extra $1600 for the OMNI? First, I've seen plenty of Corsair
2's at hamfest for $600. Used Omni 6's sell for around $1800 to $2000. So 
we are talking about $1200 or so difference. There are other alternatives
for less $$$. I all depends on what you want and are willing to put up with.
Steve Ellington N4LQ@iglou.com

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