Now that is interesting, Roy. I was going to put up a 160 m inverted L this
summer. I am limited to only being able to go up about 45 feet, so I would
need about another 90 feet horizontal.

Are you suggesting that it might be a better arrangement to go up the 45'
and then put up the top "T"? If so, roughly how long should the top part of
the T be (each side of center) to get me to 160? I'm guessing it may not be
accomplished without some base loading...and that is what took me to the
Inverted L in the first place...direct coax feed, albeit not a particularly
good low angle radiator.

I am prepared to put down a radial field...but I want to stick with a simple
vertical wire, either extended horizontally as an Inverted L or as you
suggest, a T, if it can be done. I have about 100' either side of center
available to construct the top part of the T. In either case, the top
loading wires will need to be somewhat of the inverted v construction, as I
don't have 45' high supports for each end.

Thanks for any thoughts you might have. I need to get something done before
winter!

73,

....hasan, N0AN

"Roy Lewallen" wrote in message
...
To determine the horizontal wire current, download the free EZNEC demo
from http://eznec.com. That's exactly the kind of thing it's good for.

If you put a single horizontal wire out to make an L shape, the wire
radiates a considerable amount. Being as low as it is, a lot of the power
will be dissipated in the ground, and only a small fraction will be
radiated at a low elevation angle. But if you connect to the center of a
horizontal wire to make a T shape, the fields from the two halves of the
horizontal wire will nearly cancel, so it'll radiate very little. Its main
effect, like a capacitive top hat, will be to even out the current in your
vertical wire, which will raise the radiation resistance and therefore the
efficiency.

EZNEC or a similar program will quickly show you the differences in field
strength in various directions for the antenna as it is, and with either
of the top loading configurations.

Roy Lewallen, W7EL

dansawyeror wrote:
Roy,

Thanks. This might be feasible. The site would support 50 foot wire from
the tip. At 500 watts what would the current in the horizontal leg be? In
other words what is the minimum effective gage?

What is the purpose of this leg? Is it capacitive or does it begin to
look like something else. What are it directional characteristics?
Dipoles nodes are perpendicular while long wire nodes are parallel.

Dan

Roy Lewallen wrote:

Frank wrote:

. . .
I agree with comments about adding a horizontal wire to the top of the
vertical; it will probably be easier than a capacity hat. I am
overloaded with work at the moment, but would like to attempt a model
in a week or so when I have less work.



Take a look also at a tee type arrangement. That is, a horizontal wire
with the tip of the vertical connected at or near its center. It might
have some advantages over connecting the wire's end to the vertical. But
of course it might be more involved to construct.

Roy Lewallen, W7EL