YES, we see it at Alpha, the amplifier wattmeters have a failed Schottky
diode which then causes a gain fault by the amp protection circuit. Usual
cause is gross overdrive from radio, or static on antenna.
73 - Glenn AE0Q
On Sat, Jan 9, 2010 at 9:54 PM, Dennis Ashworth <dennis@ashworth.org> wrote:
> More information on the low power condition discussed below:
>
> I suspect the inaccurate SWR reading on the internal meter is causing
> the drive to be reduced to the driver/finals. The drive reduction
> feedback loop is a protective circuit to keep from damaging the finals
> when improper loads are encountered. I'll bet the inaccurate SWR
> readings (3.:1 into a dummy load) are caused by one or both defective
> Schottky diodes in the SWR directional coupler circuit. Does this sound
> reasonable? Has anyone seen this before? Other things to check?
>
> Dennis, K7FL
>
> ===
>
> -------- Original Message --------
> Subject: OMNI VI - Low Power output
> Date: Sat, 09 Jan 2010 11:20:10 -0800
> From: Dennis Ashworth <dennis@ashworth.org>
> Reply-To: dennis@ashworth.org
> To: TenTec@contesting.com
>
>
>
> The power output of my OMNI has dropped to around 30 watts, as measured
> on the OMNI front panel and an external power meter. The collector
> current (as displayed to front panel meter) is about 15 A. SWR
> indication on the front panel is incorrect, indicating 3:1 into a dummy
> load -(1:1 indicated on the external power meter).
>
> Any ideas?
>
> Tnx
> Dennis, K7FL
>
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>
--
"Remember, any tool can be the right tool!" Red Green
AE0Q ex: GM5BKC, ZB2WZ, V31RY, SV0WY, WA0VPK
ae0q@arrl.net --SOWP 5558-M, ARRL LM, QCWA LM, OOTC, NCVA--
http://www.radiotipsandtales.com
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