[TenTec] Alpha 89

Merle Bone merlebone at charter.net
Mon Apr 14 20:30:54 EDT 2008


Bob McGraw said:
" Specifically, in the Omni VII, the radio outputs RF before the N.O.
>> actually
>> relay for control of external items closes and settles.  I had to deal
>> with
>> this when using it to control my sequencer for the VHF and UHF station
>> where
>> there are lots of things to switch an settle before producing RF from the
>> transceiver.  It is only a millisecond or so, but the RF is there.  This
>> could spell "bad" for a PIN switched amp."
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RF appearing before the keying relay in the Omni VII "closes and settles"
is a bug and should be reported. The Orion spec's RF appears approximately 
15 milliseconds after the keying relay closes. The Omni VII manual also specs 
15 milliseconds on page 17 - segment 35 "AMP KEY." 

The pin diodes in the Alpha 87A switch in "a few microseconds" not milliseconds. 
Generally speaking, the exciter probably can't create an RF leading edge before
the pin diodes switch. But any amp that outputs RF before the keying line switches 
will create system problems. 
73, Merle - W0EWM



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