[CQ-Contest] two radios on same band (10m contest)

[Steve London]

100m is a very good separation on 10 meters, if you have that much space.

I was just doing some measurements this morning between two 6 element, 
10 meter antennas that are about 50 meters apart. One is 25 meters high, 
the other 10 meters high.

Pointed at each other at 1500 watts, 2.1 watts is delivered into a 50 
ohm load. That is way too much for any receiver without protection. Even 
at 150 watts, 210 mW is too much. Obviously, this is a worst case. In my 
situation it would happen when one antenna is pointed JA, the other 
South America. For the orthogonal situation of both antennas pointed at 
EU, 1500 watts would result in only 2 mW into the other receiver.

73,
Steve, N2IC

On 11/28/2013 08:30 AM, Peter Voelpel wrote:
> With 100W output I can do that without any filtering.
> Antenna one is at 41m above ground and 100m away from antenna two which is
> 12m above ground.
> 10kHz difference in frequency are enough to operate SSB without qrm from
> either radio.
> Probably using different polarized antennas will be as effective.
> For in band filtering you will need xtal front end filters.
>
> 73
> Peter
>
>
> -----Original Message-----
> From: CQ-Contest [mailto:cq-contest-bounces at contesting.com] On Behalf Of
> Kevin McGrath
> Sent: Donnerstag, 28. November 2013 03:55
> To: cq-contest at contesting.com
> Subject: [CQ-Contest] two radios on same band (10m contest)
>
> I would like to get some advice on running two radios on the
> *same* band, specifically for 10 meters.There’s plenty of good information
> here and
> on the web regarding minimizing interference when running multiple radios on
> different bands, but not much info at all on the same band.
>
> The plan is to enter the ARRL10m contest, multi-op, mixed
> SSB/CW, low-power (<150 watt) category and use a run radio and a multiplier
> radio (only one transmitter at a time).  To
> help minimize interference, one radio would be on CW portion (say below
> 28.050)
> and the other on SSB (above 28.400) and thus maintain at least a 350-400kHz
> frequency
> separation. Also the antennas for each radio will be different
> polarizations. But
> given space limitations at the QTH, the antennas can only be separated by
> 100’.   Are
> commercial bandpass filters or homebrew designs available for in-band use?
>
>
>   I’m guessing two
> radios have been successfully used for the 10m contest. Any ideas or tips on
> the setup for minimizing inter-station interference would be greatly
> appreciated.
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