Don,
Good suggestion. Let me suggest a variant that at least two of use
are using. I use it because of my severe space limitation. Basically,
the antenna is an inverted L that is fed at its center at the top of the
vertical run thereby obviating the need for a ground. It has a total
length of a about 1/2 wave, but half is vertical, or nearly so, and the
rest runs to a convenient tree that is a little lower than the tree
holding up the vertical piece. I feed it using 450 Ohm ladder line to a
4:1 current balun where I transition to coax.
I ran an Eznec simulation of this antenna. It appears to play really
nicely on 80-30 meters, and the lobes get a little crazy starting at
about 20 meters. On the air, performance appears to agree. The downside
of this antenna is the vertical piece is susceptible to local man-made
noise. This is far from a perfect antenna, but I sure can work DX and
locals.
Let me restate that this is not a perfect antenna. I started down
this road as the upper bands are not going to be great as we slip lower
in the solar cycle and I wanted to get DXCC on 80 and 40. This antenna
does lay down a low lobe on both bands and losses are reasonable. A good
horizontal antenna will have a higher radiation angle at the support
heights I have. This is my way of dealing with the problem of getting
low angles with reasonably high supports. If I had 100+ foot supports
around, I might look at some other option.
73 & Happy New Year,
Barry
K3NDM
------ Original Message ------
From: "Don Wilhelm" <donw...@embarqmail.com>
To: "Terry Brown" <n...@comcast.net>; elecraft@mailman.qth.net
Sent: 1/1/2017 9:44:06 PM
Subject: Re: [Elecraft] Need help from an EZNec user on a horizontal
loop question
Terry,
Have you considered an 80 meter inverted L?
It takes up little real estate for the radiator, but does require
putting down a ground screen at the base of the inverted L.
If you do not wish to bury 32 radials for a ground screen, consider
using resonant elevated radials. Two elevated radials running in
opposing directions will do the job nicely.
Put the elevated radials above ground by about 10 feet to keep them out
of the range of humans and deer and other things running into them and
causing harm. If there are horse riders who will be riding through
your property, you may want to increase the height to 15 feet.
73,
Don W3FPR
On 1/1/2017 4:55 PM, Terry Brown wrote:
I am moving from my current QTH where I have a horizontal loop up
about
35-40 ft. that is a bit longer than 1 wavelength on 80. I feed it at
one
corner with 450 ohm twin lead connected to a 4:1 voltage balun, then
coax to
my rig. I can tune all the ham bands either barefoot to my K2 or KX3
and
the KXPA100 using their internal tuners.
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