[TowerTalk] replacement guys (was ...and C31XR)

[Jim Lux]

At 10:11 AM 9/21/2005, StellarCAT wrote:
>I will see if I can find it again - I may well have done him an injustice to
>quote without the reference.
>
>I would however respectfully disagree with your assessment -
>about being dead wrong. The point is that if guys are cut to be
>non-resonant and they are by nature further away from the antennas
>and in the wrong plane than the amount of coupling is insignificant.
>If this were not true than antennas like the C31XR and many others
>would not work - they are no different! Metal IN PLANE cut to be
>non-resonant.
>Granted the antennas are designed around the existing elements but again
>they
>are in the plane and they are very close.
>
>g.
>
>----- Original Message -----
>From: "Tom Rauch" <w8ji at contesting.com>
>e plane in most cases,
> > can be cut to be non-resonant,  and for the most part are
>a long distance away.
>
>It would be interesting to read the "article", because it's
>dead wrong if that is what it actually says.
>
>The issue isn't adding controlled gain. The issue is pattern
>distortion.
>
>73 Tom

As Tom points out, you can do a lot of stuff and not change the forward 
gain or the beam squint all that much, however, the placement and depth of 
nulls is another story.

So the question becomes how much pattern distortion is too much?
Changing a -20 dB null into -14 dB?
Changing a 15 dB F/B into 10 dB?

It would be pretty easy to come up with an approximation that could answer 
these sorts of questions. It's done all the time for phased array errors to 
estimate worst case and/or integrated sidelobe levels.

As far as in plane vs out of plane, the coupling is roughly proportional to 
the cosine of the angle between the two elements.

Jim, W6RMK