> Steve Katz wrote:
> >
> > Hi Jon,
> >
> > Re G5RV on 80m, I like to think of it as leaky dummy load. It's
> >amazing how much better a simple 125' dipole works, at only 23'
> >longer...
>
> Right on on that one! I had one up here for about a week and
> don't think I've used a worse antenna. A random length of wire
> worked better.
>
[Steve Katz] I agree with you, although others have reported their
G5RV's working all the planets and several distant galaxies with no
problems. I guess "whatever works" for you is the right thing to use.
Personally, I've deployed G5RV's several times since the original RSGB
article 30 years ago and always found they work well on 20m and pretty
mediocre everywhere else. But, again, that's when I compare them to other
antennas that I have installed at the same location, not a stand-alone
evaluation.
> Another good antenna is the inverted L. I have one for 160 and
> it works great. If I had 37' vertical and 150 feet horizontal
> one could be put up for 40, 80 and 160 thrown in for good
> measure. Don't know how they model in NEC or anything, just that
> it works. I've always wondered how an antenna can be modeled in
> NEC to give a reading like "3.2db" or "5.1db" gain. Especially
> on a vertical. It seems there are just too many variables to
> model. How many radials? How long? Are they buried? Are they
> laying on the ground? Are they elevated? Is it wire? Tubing?
> If tubing, is it tapered or not. How far apart are the ends of
> the radials? What kind of support? If metal, how far away is
> the wire or does it just stick up in the air by itself? How is
> it fed? Directly? Through a matching device? I think a better
> figure would be "around 3db" instead of "3.2" absolutely.
>
[Steve Katz] Well, you know how computers work, Tom. They surely
don't know how to round off. Actually, the latest easy-to-use NEC variants
like EZNEC do allow you to punch in a lot of the variables, including height
above ground, radial lengths and heights, etc. The more you feed it, the
more it tries to find the 3.20144739 dB. Still, the models can be fooled
pretty easily, I find. But then, I have daily access to a 10m anechoic
chamber that's good from about 100 kHz to 10 GHz or so, with automated
equipment to provide multiple polar plots on any emitter, minus all
reflections. Which of course, is not "real world," since there are always
reflections, but the data's useful nonetheless...
-WB2WIK/6
> Tom W7WHY
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