Topband: KD9SV-OK1RR relays ??? (RX Front End Protector)

[Martin Kratoska]

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 at 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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