Array Solutions offers a 'RX Front End Protector' based on back-to-back
1N4148 diodes.
Schematic:
http://www.ok1rr.com/public/rxfep.png
more details:
http://www.arraysolutions.com/Products/as_rxfep.htm
manual (also pictures of clipping etc.)
http://www.arraysolutions.com/images/AS-RXFEPdatasheet.pdf
It works as described, no problems although it can cause spurious
radiations on densely equipped multi-multi contest sites using very high
power amps. For single TX DXer it can be possibly preferred over relay
devices we talked about. Anyway, you test!
BTW if the AS-RXFEP will be housed in a plastic box it will provide a
lot of additional CM suppression.
73,
Martin, OK1RR
Dne 30.8.2015 v 21:52 Mike Waters napsal(a):
How about back-to-back 1N4148 diodes (2 in series) across the RX path, and
a #47 incandescent lamp between those and the Beverage? That's what I do
here, among other things.
Those are in series with my preamp, which is almost always on. There's also
some variable resistance in series with the lamp and the Beverage switching
relays. I do that so that the signal from the Beverage is equal with the RX
signal from the inverted-L.
73, Mike
www.w0btu.com
On Sat, Aug 29, 2015 at 8:06 PM, Charles Cu nningham <
charlie-cunningham@nc.rr.com> wrote:
It seems to me that a very fast operating preamp protection circuit could
be
constructed employing a good fast saturating NPN switching transistor
across
the antenna path.
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