RadioBanter - View Single Post - How can I measure or observe my hf antenna's take off angle?

March 5th 05, 06:07 AM

wrote:
Don't professionals use the term?

I don't believe so.

Seems like it shows up in pro computor
programs.

Yes, it's a carryover from the amateur programs. Brian Beezley, K6STI
was, I believe, the first to use it in an antenna analysis program. (You
won't find it in NEC-2, NEC-4, or even MININEC.) Those of us who
followed were pretty much forced to include it because of demand from
the amateur customers. I can't speak for other programs, but it's in
EZNEC pro simply to keep the amateur and pro programs similar.

Doesn't the Antenna handbook refer to TOA ? I do know they made a graph of
incoming
RF ray angles which amounts to the same thing.

The ARRL Antenna Book probably uses TOA. It's a publication intended for
amateurs. No, a graph of incoming ray angles is not a graph of TOA as
used by EZNEC and other programs. You've just given a good example of
the misunderstanding and confusion that the term is subject to.

What is wrong with the common
perception
that it is the angle of maximum gain?

Nothing at all. It's just that a lot of people think it means something
else. In some of your postings, in fact, I get the sense that you don't
always use it with that meaning. For example, you sometimes seem to give
a lot of weight to the TOA as a figure of merit, and none at all to the
field strength or gain at the angle at which communication is taking
place. So either you're using TOA in a different sense, or you have no
interest in maximizing the ability of an antenna to communicate effectively.

If you were designing a 'point to point' antenna would you not look for the
angle of maximum gain?

No, and there's an example of the perception problem. If you don't
understand why, please go back and re-read posts I've made in response
to your earlier postings on the topic.

If so what would you call that angle ?

In EZNEC, the term takeoff angle means exactly that. My well-confirmed
fear is that people would use it as you seem to be doing.

If you are refering to an antenna
lobe pattern could you not invoke
the +/- 3 db points as used in many other places in antenna work?

Lobe pattern? Invoke? Sorry, I have no idea what you're asking.

Methinks that people are looking for problems to argue about
Art

On that we agree.

Roy Lewallen, W7EL