[CQ-Contest] SO2R technical questions

[Jim Brown]

On Tue,1/20/2015 1:40 PM, Mike & Coreen Smith VE9AA wrote:
> How can I tell if I have too much energy at the input of "radio 2" when
> transmitting on "radio 1" ?

When the smoke comes out of the front end transistor.  :)

> Is this too much signal?

See above. W2VJN's excellent "Managing Interstation Interference" 
addresses this, and is a must-read. Lots of detailed advice, all of it 
solid.

http://www.inrad.net/product.php?productid=248&cat=148&page=1

> I can build some coax stubs over time.

In addition to the W2VJN book, also see k9yc.com/Coax-Stubs.pdf  for 
detailed advice and tutorial stuff that complements George's book. It's 
tricky to use stubs on multi-band antennas though -- you have to switch 
them, and both the switch and the coax between the switch and the Tee 
where they are inserted are part of the stub.

> ..and I am working on a YCCC SO2R box
> as time permits but don't have a lot of spare dough for BPF's (2 of them
> would run me $1200-$1400 CDN by the time I had them in the shack)

The TXBPF kits that 5B4AGN puts together are first rate, second only to 
the W3NQN-designed filters that Array Solutions sells for a lot more money.

> nor a SIX-PAK(another $1k_),

One of the YCCC guys has designed a kit to do that. Poke around for it.  
I'm thinking about building one.

> If I am willing to leave the amp turned off (sigh..), and antennas will all
> be separated only 50', how do I know if I have too much signal at the input
> of the 'other' radio?


> Oh and feel free to school me on SO2R

Practice, practice, practice, during contests, of course. I'm no expert, 
although I've been banging away at it for nearly 3 years, and gradually 
getting better. It does make most contests a lot more fun.

> p.s.- I will sorely miss using the amp, but if I try SO2R @ 100w and like
> it, maybe I can stumble onto some cheap 419 BPF's

You don't want one -- it's a dog.  Several years ago, I tested several 
bandpass filter sets and wrote up this review that eventually was 
published in NCJ.

http://k9yc.com/BandpassFilterSurvey.pdf

I'd guess that in most contests, an amp is worth more than 100W SO2R.  
FWIW, NAQP is a great one to get your feet wet -- simple exchange, 100W 
max, no cluster.

73, Jim K9YC