Thread: New antenna
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Old October 12th 07, 03:43 AM posted to rec.radio.amateur.antenna
art art is offline
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Default New antenna

On 11 Oct, 18:58, JIMMIE wrote:
On Oct 11, 6:45 pm, John Smith wrote:





JIMMIE wrote:


...


I dont have EZNEC, But I will trust you if you care to model a 1/4wl
monopole and compare it to an 1/8wl monople operating against a
perfect counterpoise. Fine enginneer that Art is he should have no
trouble in calculating field intensity at a receiving antenna 1 mile
away. I have total respect for the integrity of your work as long as
you show your math.


Jimmie


No.


We are talking about a small antenna ~25% of full 1/4 wave length which
performs as well or outperforms its full length 1/4 wave version.


We are talking about a 1/2 wave antenna which is only 20-30% the length
of its full length 1/2 wave version which performs as well or even out
performs its' full 1/2 wave length ...


Show me an EZNEC model of what the Navy tested for Mr. Vincent--indeed,
show me where anyone before Mr. Vincent was able to demonstrate a
working model capable of the above characteristics?


JS


http://www.fi.uba.ar/materias/6654/d...FMFAntenna.pdf

Probably more than you ever wanted to know about short antennas.

Jimmie- Hide quoted text -

- Show quoted text -


Now a bunch of erronious information
He states for short antennas a good ground field is paramount
which is false. It is correct for a fractional wavelength antenna
but not for a short antenna. Then he goes on to relate a top hat with
efficiency
so the question is does the top hat make radiation per unit
length the same terminology as efficiency since the top hat does not
increase height?
Basically, if you have a fractional wavelength antenna then a ground
plane is
paramount to provide a low resistance to ground (power loss)for the
the ANTENNA circuit.
If a low resistance path to ground is not there then the
system is closed by the outside of the feed sheathing to transmitter
ground
which closes the ANTENNA system providing combination radiation as
well as system loss.
I say again, one must have equilibrium for maximum efficiency and that
requires a full wave length
radiator and at the same time holding to the LC ratio for that
length.
These are cardinal rules as shown by Gauss.
Regards
Art KB9MZ