Doug,
The forward voltage drop of a single normal switching diode in the
conducting state is about 0.6-0.7 volts. Are you advocating two in series
and then "back to back" for both polarities?
I believe ICE uses just one pair of diodes, back to back (0.7 volts
clamping), but had a 27 Ohm 1/2 Watt resistor in series with the receive
line to the diodes so the diodes don't blow up under high RF input but are
current limited.
Any comments on that?
73,
Joe, W1JR
At 02:12 AM 9/10/2002 -0400, Doug Waller wrote:
> > The problem of protecting the rx front end while transmitting is a simple
>one.
> > Its very important NOT to use an extra RX jack (which most Radios have
>these
> > days)for beverage connection> 73 de wolf -df2py-
>
>The easy way to protect the RX only front end is to shunt the receive only
>jack externally, with two switching diodes connected polarity reversed.
>I.C.E. uses this config. successfully in their preamps.
>
>IN914/4148 type, 75piv diodes were available a year ago from Radio Shack at
>10/$1.50. I believe these shunt at 1.7 volt and they seem to have no effect
>on weak signal performance, when inserted in the coax lead-in system.
>
>73, Doug / NX4D
>
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