"Antonio Vernucci" wrote in
:

....
the results you got on EZNEC are encouraging. Nevertheless I would not
like to try using a lengthened element in conjunction with a
capacitor, as the difference between that configuration and the
original configuration would be the maximum (although it would be much
easier to adjust a capacitor than the inductance of an hairpin).

Tony,

Some thoughts.

You are suggesting that it is easier to make a low loss capacitor that is
located at the feedpoint in a hostile environment, than it is to make a
low loss inductor (the hairpin).

Just as the hairpin is a s/c stub for inductive reactance, you could use
an o/c stub... but remember that transmission line elements are a path to
low Q reactors, use thick conductors for the transmision line (which for
an o/c stub will need to be much longer than for the s/c stub).


What puzzles me is that the antenna manufacturer reported me having
sold several hundreds of those antennas, and no one has reported him
the bandwidth being too narrow or the exagerated wet terrain
influence.

Only hundreds?

Hy-Gain have used this feed system on 2m antennas for a very long time.
Yes, their gain figures seem a bit generous, but the hairpin is a viable
commercial option.

I am not sure on what I am going to do, also because I am not 100%
sure on whether the bandwidth problem is only due to the matching
system, or it is also due to the particular antenna design.

My gut feeling is that optimised long Yagis have narrow bandwidth because
of the large number of elements with role that is frequency critical. A
short Yagi has wider bandwidth with the same feed system.

It is a long time since I read your first post, but narrow bandwidth can
be an advantage. It reduces out of band signal reach your first amplifier
where it will mix and produce IMD products that may be in-band. Narrow
band antennas help to provide the selectivity that is lacking in many /
most modern radios.

Owen