On 4/23/2011 2:20 AM, Charlie Gallo wrote:
> As I said before, I have a SMALL NYC lot (42x98)
Your lot is the same width, but about 30 ft shorter, than what I had in
Chicago. I suggest that you try to install one of the Hypower loaded
dipoles for 80/40M as an inverted V, getting the center and each end as
high as possible. Do NOT buy one that is designed to cover lots of bands
with more than one set of loading coils -- they don't work very well --
but the ones with one set of loading coils work VERY well. You can also
add a fan element to the 80/40 model to cover 20M. And/or you could put
up a second tri-band fan for 20/15/10.
Try to install it so that it is broadside to EU and VK -- this will put
nulls in directions that hurt the least. It's important to realize most
of the radiation from an antenna is the part(s) that carry the most
current. For a dipole, that's the center of the antenna, so getting that
part of the antenna up high will maximize its performance on 80M. It is
FAR less important what happens to the ends of the antenna, so they can
almost hit the ground and the antenna will still work. In Chicago, I
used simple TV mast to elevate my dipoles. Not pretty, not very robust,
but I guyed them so that they were "good enough." Perhaps you can get
one end up higher than the other. That's fine. In Chicago, I stuck a
couple of 10 ft sections of TV mast on the top of my garage to hold one
end of my 80/40 dipole. I managed to work EU and SA fairly well with it
on 80 and 40, and even some JAs a bit after sunrise.
In general, dipoles, even fairly low ones, are likely to beat verticals
that don't have decent radial systems or a counterpoise to carry the
return current. With any antenna for 80/75M, and for most multi-band
and/or loaded antennas, you WILL need a decent antenna tuner.
Study the two links on my website that discuss Antennas for Limited
Space for more ideas and detailed construction techniques. One is text
and the other is a Power Point. Both are pdf files.
http://audiosystemsgroup.com/publish.htm One trick I used was to
improvise a vertical for 80 and 160 by tying both sides of the dipole
feedline together, and using a big wrought iron fence that ran around
the front of my lot as a counterpoise that I added to a dozen or so
radials. That worked very well on 80 and 160 (better than loading it as
a dipole on 80), but not on any higher bands.
73, Jim K9YC
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