[TowerTalk] precipitation static & folded verticals

[N5NUG]

The folded top loaded vertical was resonant at 7 Mhz with the folded
skirt system coupled to the feed line through a series capacitor.
The structure's natural resonant for a (30 ohm +/-) feed point was
at 2.4Mhz with just the mast and top hat. You are correct, the two
structures are very different in that respect.

So, are you saying the top loading contributes significantly to the
capture area of the antenna to invalidate the test results? If so, I
will withdraw my comments about the test.

But, before I do, can you (Yuri) explain to me why the electrically
longer (folded and top loaded) structure was inherently quieter than
the naturally resonant monopole structure when they are both
resonant at the same frequency? I sure don't know the mechanics
here. Can you give me some basis for the results of the test or
where I went wrong? 73, Ed - N5NUG

K3BU@aol.com wrote:
> 
> In a message dated 1/22/2001 12:36:50 PM Eastern Standard Time,
> n5nug@ix.netcom.com writes:
> 
> >
> >  I compared a 34' tall 40m vertical monopole antenna located about
> >  75' from  a 31' top loaded folded vertical (4 skirt wires) antenna
> >  about 8 years ago. I compared the two antennas A-B fashion on 40m
> >  for noise as well as signal strength. The monopole was matched with
> >  a loading coil to the 50 ohm feed line. The top loaded folded
> >  vertical was capacitor coupled to the skirt system for a 50 ohm
> >  match. Both antennas had the same number of radials (60) 34' long
> >  (thanks to a neighbor to my east).
> ...
> > Top loading was via a 17' diameter (8 spokes) top hat assembly with the
> > outer perimeter of the spokes tied together with #14 wire. The
> > natural resonance point for the top loaded vertical was about 2.4 Mhz.
> 
> It appears that two different antennas were compared, with different
> radiation patterns. One quarter wave (monopole) vs. top loaded folded
> vertical that was resonant around 2.4 MHz. Folded vertical would have
> different pattern (lower angle and more gain), so comparing them and serching
> for answer to cure for precipitation static is not exactly appropriate.
> I think that comparing monopole to shortened, loaded and folded vertical
> resonant on the same frequency (same pattern) would be more representative.
> 
> Yuri, K3BU
> 
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Anyone else care to contribute? 73, Ed - N5NUG

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