I just saw your end note relating to the aux port. I would still try
isolating that part of the circuit by testing the circuit with the antenna
closer to the 20 dB attenuator stage. Of course, you can also test the
diodes, but be forewarned that this circuit board in one of two that is
nearly impossible to work on.
From: Paul Christensen <firstname.lastname@example.org>
To: email@example.com <firstname.lastname@example.org>; Clark Savage Turner
Date: Tuesday, November 10, 1998 11:06 PM
Subject: Re: [TenTec] OMNI VI deafness
>I would first suspect one of the three 1N4007 quasi-PIN diodes in the T/R
>circuit. I replaced mine with Microsemi UM-2110 1KV true PIN diodes made
>specifically for high power H.F. transmit switching. Main-to-Aux antenna
>isolation also dramatically improved for use with low band beverages and
>loops. Try connecting your antenna to the AUX antenna port.
>From: Clark Savage Turner <email@example.com>
>To: firstname.lastname@example.org <email@example.com>
>Date: Tuesday, November 10, 1998 10:59 PM
>Subject: [TenTec] OMNI VI deafness
>>Gads, my OMNI VI luck is down this last few weeks.
>>I was fiddling around with a 160 meter antenna and using a
>>tuner ... and there was clearly some RF flowing back around
>>the shack. The rig (power supply) shut down pretty quickly
>>when I pushed the power up at all.
>>I did this twice, now the receiver is deaf. It can
>>hear the rig next to it tuning up (barely) but nearly
>>completely deaf to the band with an antenna connected
>>(I can just almost hear a signal that is 20 over 9 on
>>my other receiver).
>>Anything obvious? Is there a diode in the receiver antenna
>>line to protect the front end that may have fried itself
>>that I should check? (Is this part of the aux line too...
>>the receiver can't hear through the aux antenna line either.)
>>FAQ on WWW: http://www.contesting.com/tentecfaq.htm
>>Administrative requests: tentec-REQUEST@contesting.com
FAQ on WWW: http://www.contesting.com/tentecfaq.htm
Administrative requests: tentec-REQUEST@contesting.com