Not much of an antenna per Cebik
 

BTW, bought the "Vhf" collection from Cebik
and the model eznec files are pretty good! Would
recommend them, BUT be awa SOME will NOT work
as downloaded (as ELNEC/EZNEC is limited to 500
segments). At least one had over 1000 segments!
be sure to reduce these segments IN SAME (or
similar) amounts, until they are under 500
segments (right hand column) total! then they
run fine! A very interesting collection of
antenna files and worth every penny!
As info, Jim NN7K



Irv, you are correct when you stated it was a big site!
I spent a lot of time reading readers comments until my eyes glazed
over.
It was like reading every quabble from our own archives for the last
twenty years.
I think I will have to read the Cebik articles for myself and trace it
down that way
which will be much more educating. I am glad however that I used the
word "atributed"
rather than stating it as a fact. I will continue with this progect
Regards
Art

Not much of an antenna per Cebik
 

Jim - NN7K wrote:
BTW, bought the "Vhf" collection from Cebik
and the model eznec files are pretty good! Would
recommend them, BUT be awa SOME will NOT work
as downloaded (as ELNEC/EZNEC is limited to 500
segments). At least one had over 1000 segments!
be sure to reduce these segments IN SAME (or similar) amounts, until
they are under 500
segments (right hand column) total! then they
run fine! A very interesting collection of
antenna files and worth every penny!
As info, Jim NN7K

EZNEC+ allows 1500 segments.

Roy Lewallen, W7EL

Not much of an antenna per Cebik
 

how many s-units more exseptional gain does your v have compared to my
dipole at 20 feet?

On May 30, 9:02 am, art wrote:
I read a comment attributed to Cebik where he stated that any
antenna that is not 1/4, 5/8, 1/2 or 1 wave length is not much of an
antenna !
This is a false statement especially when one considers an antenna
element
based on 1 WL. This antenna is widely used and well described
in all antenna books.
I have modelled a similar arrangement in Gaussian form
where the elements are bent into a Vee shaped like yagi with elements
extremely close together where it provides exceptional gain and
pattern
and can be related visually to a bent long boom but without
elements.
A planar antenna can also be made with a similar length of radiator
with
a variable resonator that makes it applicable to a continuous10 thru
20
antenna wherein the resonator serves as a radiating portion instead
of
the normal coax stub. Also ideal for S.W. listeners on intervening
frequencies.( See Cecil's antenna page which uses variable stub
lengths instead of a variable resonator)
Seems like a lot of mis information is being given out with respect
to
antennas apparently with the silent agreement of perceived antenna
experts
and where caustic opinions out weigh technical content .
Regards
Art

Not much of an antenna per Cebik
 

Richard Clark, KB7QHC wrote:
"Sonething of a parasitic half Rhombic (or parasitic V)".

Yes, but the rhombic or Vee antenna usually needs sides which are
wavelengths long to produce significant gain. I don`t know what Art has
proposed. The TV antenna on the roof near me looks like a Yagi with its
elements all bent to the same angle with the boom. Their lengths aren`t
multiwavelength even at 200 MHz. Maybe at UHF? VHF gain would depend on
phasing between the reflector and the driven element, and the multiple
directors and the driven element. Thus its performance would begin with
its similarity with the straight Yagi, I`d wager.

Before cable and satellite were available, many configurations were
tried for TV. Some were sold more on appearance than performance.

It`s tough to cover a 4 to 1 frequency range smoothly, but they tried.
Some produced decent pictures at some distance from the transmitters
over many VHF channels. Amazing!

Best regards, Richard Harrison, KB5WZI

Not much of an antenna per Cebik
 

On Fri, 1 Jun 2007 14:37:32 -0500, (Richard
Harrison) wrote:

Richard Clark, KB7QHC wrote:
"Sonething of a parasitic half Rhombic (or parasitic V)".

Yes, but the rhombic or Vee antenna usually needs sides which are
wavelengths long to produce significant gain.

I was responding to your TV antenna example that exhibited the V shape
with parasitics. The long and short wavelengths both point along the
major axis.

I don`t know what Art has proposed.

Nobody does.

The TV antenna on the roof near me looks like a Yagi with its
elements all bent to the same angle with the boom. Their lengths aren`t
multiwavelength even at 200 MHz. Maybe at UHF?

Exactly.

VHF gain would depend on
phasing between the reflector and the driven element, and the multiple
directors and the driven element. Thus its performance would begin with
its similarity with the straight Yagi, I`d wager.

Exactly (but probably not with any spectacular gain for all the
elements).

73's
Richard Clark, KB7QHC