James,
I understand your concerns and it sounds like the aluminum is
under-dimensioned.
I also understand the wish to use what you have, but that might actually be
a bad idea, depending on what you want to build.
For me, the only logical choice of material is a telescoping fiberglass pole
and copper wire for the radiator.
They are light weight and because they taper, they are not so conspicuous
when viewed from a bit farther away.
Also, they don't often break and when they do, it's usually only one section
and you can replace the individual sections for just a few bucks.
In an ice storm 2 years ago, I had a tree fall over, into my 60 ft.
fiberglass pole.
It wiped out the pole, of course, but only 2 sections broke and it cost me
just $30 to repair it.
Funny, I thought I was being specific with my rating of the 3 antennas.
"It's horses for courses."
Depends on what you want to do.
The first choice is, should it be monoband or multiband?
If multiband, I personally would only run with a VD. I hate traps (break,
lossy, collect water) and I am to lazy to put a lot of radials down.
If monoband, anything will work, as long as it is built well, following the
multitude of excellent tips we have read on this thread.
On the one hand, I hate to have to tune a matchbox, and my shortened VD will
always require a matchbox.
I purchased a 1000 Watt Palstar automatic tuner, but haven't tried it yet.
Maybe that's the solution I've been looking for.
On the other hand, 95% of my operation is on 40.
My last two years in Germany (2006/07), the only antenna I had up
permanently was my One-Armed-Bandit; the 40m with one single radial bent
back on itself.
It probably was not quite as good as any of the three antennas we discussed
yesterday, but it was close enough, broad banded, didn't need a tuner, etc.
Something for a lazy guy like me.
There's so many antennas I d like to try.... and the wife never lets me put
up more than 3 (preferably 2) except for a few days for a contest weekend,
when I put up 5 or 6 more! :-)
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Richards
Sent: Thursday, January 06, 2011 8:27 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] New and Improved Terminology (NVIS origins)
OK, Rick, I get all that. It -IS - a difficult choice and not as
clear cut as one might, at first blush, think.
As I mentioned in another post, I am contemplating making either a 20 m
vertical dipole or a 20 m vertical quarter wave with tuned elevated
radials. I purchased some aluminum tubing to make a rotatable dipole,
but I think I selected so small diameter tubing as it sorta sags and
flops in the wind if I jiggle it. I made both 6 meter and a 10 meter
dipoles from similar sized aluminum tubing, and they seem quite study
and weather resistant. Should eve hold a couple birds who might perch
thereupon. But I think I need larger, stiffer elements to go for a 20
meter design.
I am closely tuned into your comments on the logistics of raising a full
sized half-wave vertical dipole, but on 20 meters this would need a
minimum of 20-25 feet and that can be done with wooden masts, metal
masts, or even make the antenna its own mast as a stand-alone item
(one could use a fiberglass rod for the first X feet, and then run the
lower element to another, short fiberglass rod (center insulator) and
then run the higher, second element up higher. Guy the whole thing at
approx 40 foot total height. But, a 20 foot high center mounting point
is doable even with a home brew wooden mast (a friend of mine made a
mast out of coupled /doubled-up two-by-fours to hold the end of a sloper
from his tower... and I could copy that.)
But a quarter wave ground plane employing three or four approx 17 foot
radials mounted on a 15-20 foot mast on my back deck would be even
easier to make, erect, and deploy. Unfortunately, I think the tubing
have now is still too wobbly, wiggly and flexible to take the sometimes
high winds we get off Lake Michigan here in West Mich. But, I persist
with the notion because I hate to waste the tubing I purchased and have
not figured out another good use for it !
So... ALL of this discussion, from you and all the others guys, has been
of particular interest to me both academically and practically as I play
ham radio and design new antennas to erect.
So, until I figure a use for this tubing.... I will probably hang the
new OCF dipole I have built, together with one or the 6 or 10 meter
aluminum dipoles, and see how they work. I am just a bit frustrated
because the prospect of a nicely tuned, balanced and adjusted 20 dipole
or ground plane appeals to me - as my other HF antenna is an untuned,
unbalanced 43 foot aluminum monopole - which works swell, but not, I
figure, as well as a dedicated 20 meter ground plane or vertical dipole
would work on 20 m. I don't quite know what I would do with all the
greater efficiency I might have !
So, thanks for the answer. Very helpful, even if not decisive !
I would love to have all you guys over for a big luncheon, with plenty
of beer and other libations of choice, as an antenna think tank to
debate what I might actually do. We might not reach a consensus, but
I am at present suffering analysis paralysis.
===================== James -K8JHR =====================
On 1/6/2011 4:16 PM, Rick - NJ0IP / DJ0IP wrote:
> James, that is a tough call because it is not really apples to apples.
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|