>
>
>
>
>> - 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
|