On 6/15/2012 6:03 PM, W5DXP wrote:
On Friday, June 15, 2012 4:06:25 PM UTC-5, NM5K wrote:
Only in the cases of corona buildup, etc, on the
elements would that be the case.
He may be talking about precipitation static which was considerably reduced for me in the AZ desert when I converted my dipole to a folded dipole. My problem was dust storms even on a sunny day.
http://www.its.bldrdoc.gov/fs-1037/dir-028/_4096.htm
P-static is unrelated to the reception of EM RF far-field signals. It is a static charge transferred from charged particles in the air directly to an antenna. It was so bad in AZ that arcing occurred at my coax connector. I have actually seen the p-static envelope on my IC-756PRO's display.
The problem with a dipole is that one element of the dipole normally does not have a DC path to ground. When the p-static discharge takes place, it may be through the series capacitor in the receiver. With a loop antenna, including a folded dipole, the p-static usually has a path directly to ground from any point in the antenna system. It's not the only path but it certainly reduces the p-static noise although not completely eliminating it.
Of course, it is possible to reduce the p-static problems on a dipole with a parallel resistor/choke, a 4:1 voltage balun, or heavily insulated wires. Hams who live in low p-static areas of the country will invariably say that there is no such thing because they have never seen it. But hams who have lived in the AZ desert know better.
--
73, Cecil, w5dxp.com
True, but I mentioned that first thing..
"
Only in the cases of corona buildup, etc, on the
elements would that be the case. "
The "etc" including what you are referring to.. I was
just too lazy to include that in the list. :/
But say here in Houston, with the high humidity, we rarely
ever see the type static you had in AZ.
You can also see that in some snow storms from what I hear.
But I mainly want to vote against the idea that a loop, with
no static problems, has the ability to receive less noise as
far as radiated RF from other sources.
It's one of those myths "as far as I'm concerned" that needs
to be put out of it's misery.
For instance, some will claim a small shielded loop that is
indoors, will receive less noise than an equal size unshielded
loop in the same location. Have never seen that to be the
case here, when comparing them. In fact, both the loops I kept
for permanent use were regular old unshielded diamond loops.
The biggest being the PVC frame loop that is 44 inches per side
as I recall.. I have another one that is a circular loop about
16 inches dia. The large one is 7 turns. The small one I think 12
or so.
I tried using shielded loops, but the performance was the
same. I also tried using shielded loops as the coupling loop
inside the larger unshielded loop. Worked fine, but no better
than an unshielded coupling loop with no balance problems.
I kept the shielded coupling loop for the small loop, but
used plain wire on the large one. It was easier to thread
through the spreaders, and also lighter.