On 12 mayo, 22:12, Jim Lux wrote:
Owen Duffy wrote:
Owen Duffy wrote in
:

Ok, since you are discussing impedance matching, what was the effect on
VSWR bandwidth.

It seems to me that as you go lower in frequency, the inductive reactance
at the feedpoint becomes less and the series stub reactance becomes
greater, so one aggravates the other.

The question is whether the outcome is narrower than desired or available
with other matches.

Because Mosely's explanation contains so much BS, I have no faith in
anything they have said.

Aside from marketing BS..

Owen raises a good point. *You bring the feedpoint Z from 31.8+j2 to
51+j150. *Resonating the j150 with a -j150 is fine, but now,you've
effectively got a resonant circuit with moderately high Q, or, at the
very least, more circulating power between matching network and antenna.- Ocultar texto de la cita -

- Mostrar texto de la cita -

Very good and detailed análisis Jim.

Owen point it is also good, but seems to me it is a little odd biased
by the others claims of Mosley people :)
I think that if Owen "forget Mosley" perhaps he could give another
chance to the system itself. For example = not all directive antennas
needs a great bandwidth...

However 4NEC2 simulation seem to favor the system we are analyzing.
Adding an ideal reactance of -155 ohms coarsely in the first segment
to the right of the central segment of mentioned provided 4NEC2 model
with lengthen driven element and doing a 13 to15 MHz frequency sweep I
got a lightly increment on VSWR bandwidth of approximately 200 kHz and
a decreasing of VSWR at resonance from aprox 1.5:1 to 1:1 (perhaps for
the localization of capacitive reactance on model?).

Finally, maybe I am also a little biased because my third speculation
was viable and that made me feel happy, hi hi :D

73

Miguel Ghezzi LU6ETJ