Topband: City Lots

[Jim Brown]

On Tue, 30 Dec 2008 14:50:00 +0000, doktorij at bellsouth.net wrote:

>Jim,

>Nahhh, NLI is easy ;o)
> 
>Try LAX on the top band. Wasn't so bad when Earl K6SE was still 
alive
>and active, but not so "easy" any more...

In both cases, a direct result of limited antennas. Here near SF, we 
work a bunch of LAX, SB, and SDG, but not many of these guys have the 
antennas to make it to the east coast. 

>Maybe we could talk some of the "population" into moving to say NNY 
or ND? ;o) No worries about city lots there.

A year or so ago some of the MN guys did a DXpedition to ND for a 160 
contest. It would also be nice if someone did that for VE4! 

>Something else I recall seeing at Dayton, a more expensive option, 
but
>maybe worth looking at if one is serious, was pool grounds. This 
stuff
>is bonded heavy gauge copper wire in a grid and comes in rolls (five 
>foot wide by 50' long I think). It should look like a "solid" copper 
>sheet to RF on 160, 80 and 40. You may have seen something similar 
in 
>your work. This is meant to be buried and last in the ground. I 
>believe it is for meant to be for lightning protection.

When I worked in broadcasting MANY years ago, a very heavy duty 
version of this kind of thing was installed in a good-sized grid 
around the base of AM broadcast antennas, especially directional 
arrays. As an intern from EE school, I spent much of a summer helping 
the chief engineer silver-solder the ground system for a 4-tower 
array on 930 kHz. 

The reason this is a VERY good idea is that the current distribution 
in a radial system is highest close to the base of the antenna, 
falling off as you move away, so having a very low impedance close to 
the tower is more important than at a distance. 

73,

Jim K9YC