"Roy Lewallen" wrote in message
...
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

Roy,
I built basically a loaded mobile antenna that went onto an airport
building in Raleigh, NC (about 60 feet) I was reluctant to build it because
I was afraid the people that I made it for (CAP) might not know how to do
the elevated radials. I was afraid they might come back on me. I reckon I am
one of those "trial and error" hams that has tried about everything in the
last 40 years and I am still learning. Anyhoo, BOY was I WRONG! They put
the thing on the air and it really puts out a good signal! None of us have
done any measurements or NEC modeling, etc. Frankly, I was surprised as I
had done very few vertical installations (well, I've got an AV8 vertical
all-bander). All I know is, at the 60-70 foot level with tuned radials, it
really sings!

73

Jerry
K4KWH

hasan schiers wrote:
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"?

It might be. You might benefit from the radiation from the horizontal
portion of an L, and you might not. But if it's quite low, the radiation
will be mostly straight up, and a fair amount will be expended warming
up the ground. Neither will occur with a T.

If so, roughly how long should the top part of
the T be (each side of center) to get me to 160?

That's just what antenna modeling programs are for! Dust off your EZNEC
and you'll have the answer in minutes.

. . .

Roy Lewallen, W7EL

Jerry wrote:

Roy,
I built basically a loaded mobile antenna that went onto an airport
building in Raleigh, NC (about 60 feet) I was reluctant to build it because
I was afraid the people that I made it for (CAP) might not know how to do
the elevated radials. I was afraid they might come back on me. I reckon I am
one of those "trial and error" hams that has tried about everything in the
last 40 years and I am still learning. Anyhoo, BOY was I WRONG! They put
the thing on the air and it really puts out a good signal! None of us have
done any measurements or NEC modeling, etc. Frankly, I was surprised as I
had done very few vertical installations (well, I've got an AV8 vertical
all-bander). All I know is, at the 60-70 foot level with tuned radials, it
really sings!

73

Jerry
K4KWH

I spend a lot of time learning about how antennas work, and try to pass
the information along as best I can. But I find over and over again that
most people don't have the ability to evaluate things in anything but a
binary fashion -- everything has to be "good" or "bad" (or "good" and
"evil"), "theory" or "experiment", "perfect" or "no good"; antennas
either "work" or "don't work". So what I say is often interpreted as a
statement that an antenna has to be perfect in order to work well, or to
"work" at all -- whatever that means. But that's not at all what I'm
saying. Let me try once again to clarify what I mean.

Just about anything will radiate, from a dummy load on up. But some
antennas radiate a greater fraction of the applied power than others,
and some radiate more in desired directions than others. What I try to
do is to understand how they work so I can, if I want, optimize an
antenna for a particular purpose. (And I don't necessarily always want
to -- sometimes it's not worth the trouble.) But an antenna doesn't have
to be optimum in order to talk to people. It doesn't even have to be
optimum to get sixty-over-nine reports and break pileups. And it doesn't
even have to be anywhere near optimum in order to provide you with many
pleasant QSOs. You don't have to understand anything at all about how
antennas work to put one up that will give you many hours of fine QSOs
-- I must have put up hundreds without having a clue about how they
really worked, and I worked plenty of stations. And I, like anyone else
who's been around a few years, have a handful of great stories about
some really crappy antenna that worked the rare DX. (I've even done it
with a crappy antenna and QRP.) What you have to understand is that you
can work *more* stations, more reliably, if you do take the time and
trouble (and if your yard and pocketbook will allow) to make your
antenna more efficient and make it concentrate its radiation in the
directions you want. But to a lot of people, it's not worth the time and
trouble -- and that's fine.

Some people simply aren't interested in the technical aspects of the
hobby, and would rather spend their time doing something other than
learning about or even modeling antennas. There's nothing at all wrong
with that. Those folks won't find many of my postings to be interesting,
and won't read them, which is fine. And, like I did for a long time,
they'll put up plenty of antennas that work well enough -- and even from
time to time one that works exceptionally well. But I hope my postings
will be useful to those people who are interested in learning more about
antennas and/or who enjoy squeezing more performance out of them. And I
learn from this, too!

Learning about antennas doesn't diminish your ability to experiment and
successfully create working antennas. What it does is to give you more
tools, so you can -- if you choose, but only if you choose -- make an
antenna do what you want, rather than putting it up and settling for
whatever it does.

Roy Lewallen, W7EL

Roy,

Is there an EZNEC howto. I have tried to use the demo a few times and can't seem
to get started. I tried to model a simple dipole and a center loaded vertical
and got very lost.

Thanks,
Dan

Roy Lewallen wrote:
hasan schiers wrote:

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"?


It might be. You might benefit from the radiation from the horizontal
portion of an L, and you might not. But if it's quite low, the radiation
will be mostly straight up, and a fair amount will be expended warming
up the ground. Neither will occur with a T.

If so, roughly how long should the top part of the T be (each side of
center) to get me to 160?


That's just what antenna modeling programs are for! Dust off your EZNEC
and you'll have the answer in minutes.

. . .

Roy Lewallen, W7EL

On Thu, 25 Aug 2005 19:15:13 -0700, dansawyeror
wrote:

Is there an EZNEC howto. I have tried to use the demo a few times and can't seem
to get started. I tried to model a simple dipole and a center loaded vertical
and got very lost.

Hi Dan,

It would be far simpler to hit the "Open" button and select an already
existing example of an antenna and see where that goes.

73's
Richard Clark, KB7QHC

On Thu, 25 Aug 2005 19:15:13 -0700, dansawyeror
wrote:

Is there an EZNEC howto. I have tried to use the demo a few times and can't seem
to get started. I tried to model a simple dipole and a center loaded vertical
and got very lost.

Perchance have you happen to read the help file?

Hint; that information is there.

Danny, K6MHE

dansawyeror wrote:
Roy,

Is there an EZNEC howto. I have tried to use the demo a few times and
can't seem to get started. I tried to model a simple dipole and a center
loaded vertical and got very lost.

In the main window, click Help, then Contents. This is the EZNEC manual.
Read the Getting Started section, and go through the "Test Drive"
tutorial it directs you to. That should get you started.

Roy Lewallen, W7EL

All I know is, at the 60-70 foot level with tuned radials, it
really sings!

They do. I've always preferred an elevated vs ground mount
vertical. At that height on 80m, you appx equal to a ground
mount system with 60+ radials, if they are using 3 or 4.
Also, more clear of surroundings, etc.. Your local ground/space
wave will usually be better. I bet it's good to dx at 2-3 AM...
I've also used the usual L's and T's on 160m. Like Roy mentioned,
which is better will depend on the angle needed. The T is better
for strict DX, but often the L can be better to regional stuff.
I'd have to double check, but I don't think adding the other
half of the "T" top really changes the resonant freq a whole lot
vs the L. IE: when using a "T", you will still need nearly a full 1/4
wave from the base to either end of the top horizontal section
if not loaded.
What can be handy for low banders, is nearly any dipole can be
loaded up as a T vertical, if you short the conductors. Doesn't
matter what type of feedline. Loading a 80m dipole as a T on
160m, is usually far better than trying to load the dipole as a
dipole...
If you don't short the feed together, but only feed one conductor,
you then have a quicky L...Thats one quick way to compare them on
different signals to see which is best at a given time. 160 is kinda
weird...Often an L will outdo a T early in the evening, but usually
later,
the T will be better, even on the same short paths. Would seem to
indicate the higher angles are less used later at night..
Sometimes I run a 80 meter turnstyle, and feed that as a vertical with
an "X" capacity hat... That made a pretty good vertical which usually
beat
the L late at night. BTW, the vertical part of both antennas are appx
40-45 ft or so.. So fairly equal in that regard.
MK

I bought EZNEC +,v4 and enrolled in the ARRL antenna course. With my
many years of experience (bad & good!) I knew it was unlikely I would
really get much out of either....

It has turned into one of the best educational bargains I have ever
encountered. I am less than halfway through the course and find my
biggest problem is that I keep running off in all directions to check
out my past antenna failures.

My wounded ego is healing nicely and I am satisfied that I am no
antenna expert. I am a perpetual antenna student!

On Thu, 25 Aug 2005 19:15:13 -0700, dansawyeror
wrote:

Roy,

Is there an EZNEC howto. I have tried to use the demo a few times and can't seem
to get started. I tried to model a simple dipole and a center loaded vertical
and got very lost.

Thanks,
Dan

John Ferrell wrote:
. . .
I am a perpetual antenna student!

And so are we all.

Roy Lewallen, W7EL