[Antennas] 1/4 wave sloper...whats really radiating?

[n5ge at n5ge.com]

I don't have a model for the setup you have, but I have modeled my 80m half
sloper (.25wl) and tower.  In the model the mast radiates very slightly, so I
suspect any radiation of the objects above the top of the tower would be
minimal.

Half sloper's cause the tower to radiate, so the tower is doing most of the
radiation, but the azimuth pattern will be slightly skewed in the direction of
the sloping wire.

To model your tower, the easiest way to model it is to create wires in your
model that are vertical with the diameter changing when the section size
changes.  For example if the base section is 25 inches on a side model it as a
25 inch diameter wire the length of that section.  If you save the model with
nothing but the tower you will always have the tower model when you need it.

73,
Tom
Amateur Radio Operator N5GE
ARRL Lifetime Member
QCWA Lifetime Member

"Only the white eyes would believe they could cut the top
off a blanket, sew it to the bottom and have a longer
blanket."

-- American Indian comment about Daylight Saving Time --
 

On Thu, 09 Feb 2012 14:29:39 +0000 (GMT), jkolin at optonline.net wrote:

>I'm using  two 1/4 wave slopers tied to one feed point at the top section of my 90' crankup twr. One is 75M and other is 40M. They are separated by 24" pvc pipe at the bottom end of the 40M wire. I run the twr up to abt 75' and both work very well at that height. 
>
>Tower has 5 el 20M yagi on 42' boom at bottom of 12' Mast. A 3 el 10M yagi is at top of mast.
>
>I think the yagis, their booms, possibly their individual elements and the 12' mast may be contributing to the actual total radiation.
>
>I wonder how I can prove or disprove what components mounted above the slopers are actually radiating .
>
>Neon bulbs or low wattage small flourescent  3/4" dia bulbs placed at possible high voltage points?
>
>Any ideas ?
>
>Thanks...    Jay, NE2Q
[snip]