[UK-CONTEST] 4 square simulator

[Cooper, Stewart]

ON4UN gave a great talk at Dayton this year (which went right over my head) about optimising 4 square design and lobe steering. Also setting up a real system with minimal test equipment. Paper is at:
http://www.kkn.net/dayton2005/ON4UN-Dayton-2005.pdf

Stewart
GM4AFF


-----Original Message-----
From: uk-contest-bounces at contesting.com
[mailto:uk-contest-bounces at contesting.com]On Behalf Of Mark Marsden
Sent: 22 December 2005 15:52
To: UK Contest Reflector
Subject: Re: [UK-CONTEST] 4 square simulator


Ian

It gets even better, just put four random towers wherever the underlying
rock allows and then design the coefficients!

What is amazing, just try putting two wanted signals say 20 degrees
apart with an interferer in between them, and watch the optimser notch
it out.


73, Mark G4AXX



-----Original Message-----
From: Ian White GM3SEK [mailto:gm3sek at ifwtech.co.uk]
Sent: 22 December 2005 15:24
To: Mark Marsden
Subject: Re: [UK-CONTEST] 4 square simulator

Hello Mark

>
>A four-square simulator is now available as a free download. This is a
>spin-off from work done by Plextek for Ofcom's SMART antenna program
>for beam and null steering.
>
>It provides a real time display of the polar diagram and signal to
>noise ratio of multiple wanted signals and unwanted interferers. 
>Playing around with the direction of the signals and watching the
>weighting coefficients optimise gives valuable insight into what a four

>square can do.

That is sooo cool!

Please can Plextek design an array that will adaptively null out the
interferers on RX, and then switch to TX and drop big sidelobes on them?

>Changing the array size is most revealing.

I don't want to hear about *any* other spacings! Not after all the
trouble we had last week, trying to make four post-holes in an exact
0.25 wavelength square. The best that a 6-ton digger could manage was
four small scrapes into solid rock.

The tower base was actually easier - we let the hole decide where it
wanted to be.


--
73 from Ian GM3SEK
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