[Lowfer] Active Whips and Rubber Sheets

Thu, 31 Jan 2002 13:09:09 -0500

Les,

The tests I ran about two years ago indicate the E-probe signal is
proportional to the height above the ground. I ran the test in an open
field, after my back yard test, to eliminate the effect of the trees, and
the results were the same. You will also find the S/N improves with height
because you are getting farther and farther away from your grid of house
wiring and kid- controlled computers <G> that transmit nasty noise to the
E-probe.

Why do you need a mast? I installed a nylon rope over the tallest tree in
that area of the back yard and just host the E-probe up and down to make
changes.

Bill

Many of you are no doubt familiar with the "rubber sheet" theory that states
to
avoid electrostatic fields and obtain maximum performance from any
active whip antenna, you need to place it at the highest possible point in
the area.

In my case, that would be at the top of the 40 foot mast that supports the
"XM" flattop. Currently, the active whip is doing a good job at only
15 feet above ground but I'd love to do better.

So, two questions:

1. In your experience, am I likely to achieve much more performance if I
place
the whip on top of the 40 foot mast?

2. My real concern is having to lower and raise the mast for repairs. I had 
thought
about trying to rig another pulley at the top to raise and lowfer the entire
active whip case...but not sure how to really make that stable.

Tips, suggestions?

73,

Les

Les Rayburn, director
High Noon Film & Interactive
100 Centerview Drive
Suite 111
Birmingham, AL 35216
(205) 824-8930
(205) 824-8960 FAX
(205) 253-4867 CELL
http://www.highnoonfilm.com

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