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Re: [TenTec] Omni VII ATU Saga

To: tentec@contesting.com
Subject: Re: [TenTec] Omni VII ATU Saga
From: Jack Mandelman <modelman@ieee.org>
Reply-to: k1vt@arrl.net, Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Tue, 25 Jan 2011 12:26:50 -0500
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
If various mixing products were getting through the PA, why does the 
external tuner work?

I have the same problem that Curt experienced.  The tuner does not 
always achieve a good match.  Frequently it would stop tuning when the 
SWR is considerably > 2:1.  The O7 believes that a match has been 
obtained, when in fact it's far from matched.  My external ATU works 
beautifully, and the radio operates nominally on all bands and modes.   
With the tuner bypassed, output in tune is 20W; key down CW is 100W.   
Neglecting the issue with the ATU the Omni VII operates perfectly.

I'm corresponding with Paul Clinton via email concerning this problem.   
If Paul feels that the problem is with the tuner I'll most likely send 
it in for servicing, since I don't feel comfortable working with SMT 
devices.  If he feels that I should send in the entire rig, I'll 
probably remove the tuner and operate it normally as a 588 without 
tuner, using external tuners.

Would appreciate any thoughts that others may have.

Jack K1VT

> Curt, maybe the faulty filter was allowing various mixing products to pass
> through to the
> output on transmit.   If so, the antenna tuner would not likely be able to 
> find
> a match for the
> desired frequency and the unwanted products at the same time.....maybe.    :-)
> Please tell us what TT says about the matter.  Curious minds want to know.
> Glad it's working well!
> 73,
> -Lee-
> On 25 Jan 2011 at 8:12, Curt wrote:
> >/  My Omni VII arrived in good condition after a trip to the factory to/
> >/  repair a broken internal ATU.  It seems to be working fine, the tuner/
> >/  works as well as it did when new./
> >/  /
> >/  What puzzles me is Ten-Tec's note about the repair says "replaced/
> >/  defective 455 filter in transmitter chain.  Labor $150, mat'l $3"   I/
> >/  haven't a clue about what the 455 filter is or how it could cause the/
> >/  ATU to fail.  The transmitter functioned well with the broken tuner/
> >/  bypassed and using my external tuner.  What's also bothersome is the/
> >/  list of functions checked by the technician don't include anything/
> >/  associated with the ATU./
> >/  /
> >/  I've sent a note to Ten-Tec service asking for an explanation, while/
> >/  waiting for a response, does anyone on this list have any thoughts/
> >/  about how the noted defect would prevent the internal ATU to work, but/
> >/  permit the radio to function normally when not using the internal ATU?/
> >/  /
> >/  73, Curt KB5JO/
> >/  /
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