On Sat, 29 Jan 2005 16:45:29 -0800, Richard Clark
wrote:
On Sat, 29 Jan 2005 19:22:12 -0500, Buck wrote:
Speaking of Yagi's and gain, I know that the gain (and inversely the
bandwidth) of a yagi is increased by extending the spacing between
elements. A wide spaced gives a little more gain than narrow spaced
elements. I believe it also narrows the beam width of the signal.
Hi Buck,
This is fine.
I don't think it affects that TOA, though, except maybe by its
relationship to the ground and its surrounding terrain.
It is unlikely that anything you do in such a small footprint will
bring any geometric change that brings even a perceptible change to
the TOA. However, by simply increasing gain, the entire lobe
structure of the antenna increases (same shape balloon, but now a
larger balloon) which does impact the TOA; but not its angle, instead
more its magnitude. This, in a sense, was the comparison Roy was
drawing upon with the different examples.
In a sense, increasing the antenna gain (all other factors held
constant) would be indistinguishable from simply boosting the
transmitter gain (or adding an Amp).
73's
Richard Clark, KB7QHC
I think you and I are in agreement except for what Art believes. (see
his statement below
I believe it is time for antenna designers to concentrate less on
obtaining gain and instead concentrate more on lowering the TOA.
without the need of excessive real estate requirements.
He agrees that the antenna is better as it improves receive as well as
transmit, but I can't see the TOA being more important than the gain
unless it is really off by a long way. An NVIS antenna has a
different purpose than a DX antenna so he would need an antenna that
fits his needs. I am not sure what would reduce the TOA over a Yagi
unless it is a Yagi pointed downward.
Maybe what we need to be doing is asking Art what his situation is and
trying to find the antenna that best fits his needs. I can't help but
think that this question arose because he can't seem to find the
antenna that helps him make successful DX contacts.
I used a TA-33JR for years. It was a fantastic 3 element beam. It
was small, fit on my roof and could be turned by a RadShak TV Rotor.
Even though it wasn't the ideal height above ground, it made a world
of difference chasing mobiles for the WA counties award.
I try to learn a lot about antennas. I don't claim to be an expert
and certainly don't want anyone to think I am trying to make Art (or
anyone else) look like they don't know what they are talking about.
BTW, Art, have you looked at the N4GG antenna? It is on the ARRL site
for members. I built one and didn't understand it so I took it down
and made a new antenna. Then I got the details of it, but it was
promoted as being a low angle of radiation. I don't know the degrees,
though. It was certainly a much quieter antenna than the dipole.
I talked to N4GG by email. He is a real nice person.
Good luck,
Buck
--
Buck
N4PGW