> - 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
>
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