>> Moreover, when asked, TenTec has been offering ONLY for European > hams the
>>possibility to enhance the front end with some special PIN > diodes. Folks,
>>don't try this at home! Someone did and found out it didn't > work well.
>>Lets the pros do their work
Two years ago, I replaced all 30+ bandswitching diodes with HP 5082-3081
in addition to making Ten-Tec's Omni Six second-order modification
through the resistor change. Additionally, I changed all three 1N4007
T/R diodes with Microsemi Corp. UM-2110 high-power H.F. PIN diodes made
expressly for this purpose. The latter change increased my main-to-aux
antenna isolation by well over 35 dB. Now, when I depress the aux
antenna switch, there is absolutely nothing there even while tuned to
high-power short-wave broadcasts between 7.100 MHz and 7.150 MHz here on
the east coast. It's an absolute disconnection. This may not mean much
to most ops, but if you run a beverage or loop antenna on the aux input,
prior to my modification, the leakage from the main antenna oftentimes
completely masked the effect and benefit of having a separate receive
antenna.
I never measured the second-order intermod performance since installing
the HP small-signal PIN diodes. However, I was first in line to have my
Omni Six modified to the new Plus version and asked Scott Robbins to
have their techs measure mine upon completion. I'll pass along the
results when I get them
-Paul, W9AC
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