[TenTec] radios and spectral purity

[Jim Brown]

On 5/14/2012 6:58 AM, Rick Dougherty NQ4I wrote:
> just a few days ago I fired up two fo them on 20m cw...barefoot...on 14.005
> and 14.030 ...just 25 kcs away from each other into separate antenna
> systems...either could tranmit and would NOT
> hear any noise from the other...now that is AMAZING.

I'll top that!

I have a 3-el SteppIR on a 120 ft tower, and a year or so ago, I added a 
second tower and monoband antennas for 20, 15, and 10   The two towers 
are about 150 ft apart. My SO2R setup is a pair of K3s driving a pair of 
Titan 425s. Soon after getting the second tower going,  by accident I 
noticed that I had both radios on 20CW, about 50 kHz apart, and the 
radios did not hear each other -- no clicks, no phase noise!  This is 
with 1.5kW output, and both receivers set to copy weak signals -- 
attenuator off, preamp on!  Obviously, it matters where the antennas are 
pointed, and in this case, they were pointed to the east coast and the 
locations of the towers puts each antenna off the side of the other.  
I've since observed similar results on 15M and 10M during contests, and 
there are times when I'll have two radios on the same band with antennas 
pointed in different directions, one radio calling CQ, the other S&P 
(search and pounce) to find multipliers.

73, Jim K9YC