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[Amps] electronic switching

To: <amps@contesting.com>
Subject: [Amps] electronic switching
From: 2 at vc.net (2)
Date: Fri Jun 20 08:22:52 2003
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>> -  There is more than one PIN diode in a T/R switch.  During receive, one 
>> of the PIN diodes connects the transceiver to the antenna jack.  During 
>> transmit, this PIN diode must isolate the transceiver from the antenna 
>> jack of the amplifier .  In order to do this, it would seem that enough V 
>> to keep this PIN diode reverse biased at all points on the 775V-peak to 
>> peak sinewave is needed.  Is this not so?
>> 
> //It would be so if that's the circuit used.  However, why use that
> circuit?  For a BANDSWITCH, you don't need the "RX" (isolating) diode, at
> all.  For a T-R switch, whether you need an isolating diode (or more than
> one) depends upon the kind of isolation you're looking to achieve.  For
> 100dB, yep, I think an isolating diode is in order, and for high power
> operation this can require an HV power supply.  But for 35 dB isolation,
> sufficient in many cases for a 1500W TX and most modern receivers, the
> isolation diode is often not required at all, relieving this problem.
> -WB2WIK/6
>> 
**  how could it be not necessary to isolate the transceiver from the 
antenna jack on the Amp?  I would like to see a diagram.
>


Rich, AG6K, 805-386-3734, www.vcnet.com/measures

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