[Elecraft] adjacent antennas and potential radio damage

[Brian Alsop]

Guys,
There is no substitute for a measurement.  There is no global answer to 
how close is too close or how much power is too much power.

Measurement process is simple:
1) Run one rig at 1 to 5 watts
2) Look at the S-meter on the other.
3) Scale the results upward by adding the number of dB to full power.
If this results in something > 80db over S9 then be concerned.  Consider 
RX protection.

Do the same with the other rig transmitting.
You might consider doing this on all bands.

73 de Brian/K3KO


On 4/16/2014 17:08, Mike Harris wrote:
> Quite so.
>
> Forty years ago the FT101 had a front end protection circuit that
> included a light bulb.  When I was in the Antarctic, location doesn't
> really matter, my antennas were reasonably close and when I keyed the
> main TX at 1500W the rear of the '101 would flash with the keying. Never
> suffered a front end failure.
>
> I have a circuit diagram dated 2010 for an "RX Protector", which
> unfortunately doesn't offer any authorship detail, it looks similar to
> the '101 circuit.  If anyone wants a copy let me know.
>
> If the idea of a bulb and a couple of back to back diodes and big
> signals worries you then perhaps making this as a piece of test
> equipment to be used as a level reality check and then taken out of the
> signal path is possibly the answer.
>
> Regards,
>
> Mike VP8NO
>
> On 16/04/2014 12:40, Charlie T, K3ICH wrote:
>> Connect a "grain-of-wheat" light bulb across the unused coax and
>> gradually increase transmit power.
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