Richard,

Interesting, even if a bit above my current point in the learning curve.


Generally, I am experimenting with antennas here, trying to find the
junction between theoreticl concepts, and the physical realities of the
real estate, building, and trees, etc. just all hams do, I am sure.

Antenna #1 is now up, it is an OCF stung between to trees, not bad.

But now I am moving on to #2 which is this proposed 160m full wave loop.
I have collected a handful of these old masts (junk yards, the local dump
etc.) nice material to have on hand.

Here is more detail of the proposed loop, so that I can better glean
something constructive from your intriguing ideas.

Only one of the proposed masts will be resting on the ground out in the
middle of the orchard. Three are attached to buildings (adding height)
and one is attached to a sturdy wooden "telephone" pole (again adding
height and a way of mounting). The idea of putting radials in the ground
does not seem practical for most of these masts, however, your idea is
intriguing none the less.

Since I have a bunch of masts to play with, and I am in the antenna
experimental mode, and have rural real estate to play around in, I am
wondering about the antenna you have suggested.

Maybe we are talking about the possibility of Antenna #3 here.

Am I to understand that a promising antenna (you call a broadband
vertical) can be made from a single 50 foot telescoping tv metal mast,
the base of which is at ground level, utililizing the guy wires as part
of the antenna system, with a system of radials in the ground underneath?
How would I best feed this antenna, and would it be worthwhile with just
this single mast, and what advantages would such an antenna have over
others that I might construct?

At this point, I have only made plans for various wire antennas. Do not
have any verticals. The tower and beam are only a twinkle in my minds
eye, and I have to visit that neighbor who has a 75 footer he is not
using that he suggested might be for sale, but that is down the line a
way. Meanwhile I am tree fishing here, and recycling masts when I can
find them.

I have more or less concluded, that my nicest 50 foot telescoping tv
mast, is not the way to go for a "beam" and rotator, even the small ones,
the engineering of such a project seems to court a Laurel and Hardy kind
of fiasco in my imagination, at least until someone tells me that they
did it and it was smooth sailing.....

which is to say, I do not yet have a plan for some kind of antenna which
can be rotated....whatever its desing might be.....

man, there is so much to this antenna thing......it is what this is all
about.....and I love it....



-bill


Richard Clark wrote:

On Sat, 17 Apr 2004 18:14:58 GMT, zeno wrote:
I am getting ready to put up my masts (5 of them) for a 160m
full wave loop. For the most part I am using recycled
telescoping tv masts which will be up around 50+ feet.

Hi Bill,

You are on the threshold of being able to do much more for slightly
more effort.

Let's suppose you use wire with insulators to break them up (generally
only advised as a must below tower mounted beams so that opportunistic
resonances don't mess up directionality and tune).

Further, let's suppose all wires at the top have a good metal
connection to the mast.

Further, let's suppose each of these wires is broken such that the
first insulator(s) is more than 25 or 30 feet above ground (straight
down, I am not measuring along the wire).

Nothing else matters beyond what you would then do for general
construction.

I presume that all masts are driven into the ground (or at least are
not insulated from ground); and that at each mast you could build a
radial ground screen of eight to a dozen wires as broad as those first
set of insulators are out from the mast (probably 20 to 30 feet each).

You then have the opportunity of developing four broadband vertical
antennas (each with a gamma feed because of the grounded situation).
There's a good chance they would operate on 80M without too much
effort (you might push them to 160).

Most of the work is in the top connection, and the first set of
insulators - beyond that no commitments are needed if you simply
decide to walk away later. That is easy with little difference in the
up front effort.

73's
Richard Clark, KB7QHC