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Re: [TenTec] Omni VI cw signals

To: tentec@contesting.com
Subject: Re: [TenTec] Omni VI cw signals
From: "Dr. Gerald N. Johnson" <geraldj@weather.net>
Reply-to: geraldj@weather.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Mon, 17 May 2010 10:42:18 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
FT847 and FT857 are entirely different radios. The 857 and 897 are 
practically identical with the 897 package having room for an internal 
battery for portable use.

The 857s I have do very well with signal quality, though one did not 
when I fired it up last year. It had been through a super master reset 
(which wipes out all the factory software alignment and alarm trigger 
set points). That defaults SWR alarms to a level of 1:1 and among many 
other maladjustments sets a CW drive level to 255 where 50 is a decent 
value. With that drive level very high, it puts out a spike at key 
closure, then backs off and does the proper rise. When the drive 
controls are adjust to reduce the output for use with a transverter 
(which I was I was doing) that spike can be hard on the transverter 
circuits. Setting that gain way down cured that without preventing it 
from doing full power. Then I set the power settings to very low values 
and now when the front panel menu says its doing 5 watts, its actually 
doing 2 watts, and then the front panel menu says its doing 50 watts its 
actually doing 4 watts.

Used at VHF, mixed mode QSOs are common and I really like the mode of 
the 857 where the mode is set to USB, but all I have to do for CW is 
send. No mode changes, no frequency shifts or inversions characteristic 
of the FT 726 and 736 and TT Omni V and VI. That does loose the zero 
beat (blue) led indication that works only in CW mode. And the CW offset 
frequency is selectible over a fairly wide range of frequencies but only 
at 100 Hz steps.

And the 817, 857, and 897 noise blanker works very well. AGC works 
almost took good for 10 GHz operation where on has to aim an antenna 
with less than 5 degree beamwidth. One has to find the peak by finding 
the edges and setting inbetween. The option of an external analog meter 
(half as big as the radio) might be a good one to apply.

One other handy connection for the family is a TX INH line that shuts 
down RF output with a few volts applied while leaving it transmit mode, 
so VOX, or KOX or key closer puts out PTT to trigger a sequencer for the 
transverter or PA, but so long as TX INH is held high, there is NO RF 
until TX INH goes to ground. Unfortunately its not documented. It will 
be in the next proceedings of the CSVHF Conference proceedings.

On 5/14/2010 8:23 PM, Phil Chambley Sr. wrote:
> The waveform corners are adjustable with R24 on the Control Board.
> I haven't seen one yet that I felt came close to clicking, no matter how
> tight the adjustment.
> The worst rigs I've heard on CW in the past few years have been Yaesu
> 847/857 type.
> Not sure who said the Omni VI was noted for clix, but I'd like to hear the
> background.

Those reports that I mentioned were on this forum a couple years back. I 
suspect they came from the most fastidious users of the Omni VI and they 
appeared to only come from Omni VI hearing Omni VI. One of the reports 
pointed to W1AW 20 meters one afternoon. I listened with the my Corsair 
II having the same factory filters as an Omni VI and I couldn't find 
either click or chirp. That makes me think if actually present, it might 
be an effect of AGC in the receiver or the accumulated phase shifts near 
the edge of the filter passband in the transmitter and receiver filters, 
but that should be the same in Omni VI or Corsair II using the same 
filters. Perhaps its just some filters that detect that.
> Phil C. Sr.
> k4dpk
73, Jerry, K0CQ
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