Call for a *practical* design for a 5 or 6 element wideband yagi using a hertz dipole as DE
 

Hi. I'm wanting to "design" using a "simple design methodolgy". As far as I
can tell that means avoiding using models and antenna programs because I
think designing a practical yagi from a model is *not* a simple design
methodology. That's my impression.

So I think the best option I have is to take a practical design and use the
principle of scaling, and using a program that will make adjustments to the
element lengths for an alteration in element diameters and a program that
will make adjustments in element lengths for alteration in boom size. I'm
pretty sure element spacings will need not to be altered given some
reasonable alteration in either element diamters or boom size.

(Do these correction programs assume a particular element fixing method I
wonder!!. Where are these programs. I only know of ELE.EXE)

I'm looking for a practical design that uses a hertz dipole as DE, not a
folded dipole. And it ought to be wideband well, a bandwidth of about 4% of
the center frequency.

Boom needs to be metal.

I'm looking to make the center frequency 159 Mhz. So any practical design I
suppose is likely to be a VHF yagi not too far removed from 159 Mhz.

There can be a balun arrangement or not, but I don't want to feed a balanced
DE with unbalanced coax.

My antenna is to be a receiving antenna.

My email is:



Please remove REMOVE.

Thanks.

"Richard" wrote

I'm looking to make the center frequency 159 Mhz. So any practical design
I
suppose is likely to be a VHF yagi not too far removed from 159 Mhz.
My antenna is to be a receiving antenna.

Richard, I thought you wanted a marine-band antenna? The center should be at
156.300 to 156.800 mHz and will cover above that fine, but not well below
it.

Jack

"Jack Painter" wrote in message
news:Ol_xc.9311$K45.4284@fed1read02...

"Richard" wrote

I'm looking to make the center frequency 159 Mhz. So any practical
design
I
suppose is likely to be a VHF yagi not too far removed from 159 Mhz.
My antenna is to be a receiving antenna.

Richard, I thought you wanted a marine-band antenna? The center should be
at
156.300 to 156.800 mHz and will cover above that fine, but not well below
it.

Jack

I'm following two threads with my antenna muses, I don't know which one is
going to come out on top:

engaging in applying scaling, and tackling what is required when changes are
made in element diameter and boom size of a tried and tested *practical
design* one that employs a metal boom,

or following the track that seems to involve simply scaling with a *model*
and the making of other adjustments to the model, (arising from element
diameter changes) where in practical terms the model is sufficiently
equivalent to a "practical design" by virtue of the employment of a non
conducting boom in the construction of the yagi.

But to your point:

Marine band is from 156-162 Mhz. Center 159 Mhz.

Jack Painter wrote:

"Richard" wrote

I'm looking to make the center frequency 159 Mhz. So any practical design
I
suppose is likely to be a VHF yagi not too far removed from 159 Mhz.
My antenna is to be a receiving antenna.

Richard, I thought you wanted a marine-band antenna? The center should be at
156.300 to 156.800 mHz and will cover above that fine, but not well below
it.

Jack
Marine band goes up above 160 mhz a bit..If I remember right, the
boats/ patches, etc I used to hear were about 162 mhz. Been a while
though. They were above 160 mhz for sure. MK
--
http://web.wt.net/~nm5k

Richard wrote:
Hi. I'm wanting to "design" using a "simple design methodolgy". As far as I
can tell that means avoiding using models and antenna programs because I
think designing a practical yagi from a model is *not* a simple design
methodology. That's my impression.

So I think the best option I have is to take a practical design and use the
principle of scaling, and using a program that will make adjustments to the
element lengths for an alteration in element diameters and a program that
will make adjustments in element lengths for alteration in boom size. I'm
pretty sure element spacings will need not to be altered given some
reasonable alteration in either element diamters or boom size.

(Do these correction programs assume a particular element fixing method I
wonder!!. Where are these programs. I only know of ELE.EXE)

I'm looking for a practical design that uses a hertz dipole as DE, not a
folded dipole. And it ought to be wideband well, a bandwidth of about 4% of
the center frequency.

Boom needs to be metal.

I'm looking to make the center frequency 159 Mhz. So any practical design I
suppose is likely to be a VHF yagi not too far removed from 159 Mhz.

There can be a balun arrangement or not, but I don't want to feed a balanced
DE with unbalanced coax.

My antenna is to be a receiving antenna.

My email is:



Please remove REMOVE.

Thanks.


There use to be a program available written by Gunter Hock, DL6WU, that
was for designing VHF/UHF yagi antennas. It took into account boom type
and size, element size, bonding methods, etc.. The original program was
written in BASIC. For my own use, I converted it over to a JavaScript
driven web page. If you are interested I just posted it on the web at
http://www.k7mem.150m.com/Electronic.../yagi_vhf.html.
Maybe this is the kind of thing you are looking for. The original BASIC
source code is available.

I only started this web site a week ago so don't expect everything to
work completely. There are several known links that really don't go
anywhere yet.

--
Martin E. Meserve

K7MEM wrote:

There use to be a program available written by Gunter Hock, DL6WU, that
was for designing VHF/UHF yagi antennas. It took into account boom type
and size, element size, bonding methods, etc.. The original program was
written in BASIC.

There are now many different programs called "dl6wu-something.bas" out
there on the web... but DL6WU didn't actually write any of them.

The master copy of the program that Martin is using is on my 'VHF/UHF
Long Yagi Workshop' page. It was originally written by KY4Z and W6NBI,
and AFAIK it is still the only one that DL6WU has personally checked
against his original tables and graphs. For that reason it is guaranteed
to be maintained for the indefinite future.


However, the DL6WU yagis are not suitable for the OP's original request
for 5/6 elements, because these are all "long" yagis with a minimum of
10 elements.


--
73 from Ian G3SEK
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

"Richard" wrote
I'm looking to make the center frequency 159 Mhz.

Richard, I thought you wanted a marine-band antenna? The center should
be
at
156.300 to 156.800 mHz and will cover above that fine, but not well
below
it.

Jack

But to your point:

Marine band is from 156-162 Mhz. Center 159 Mhz.

Richard, my point was, your antenna will funtion better centered on the
lower part of the band, using any wideband features the antenna has to work
upward in frequency, not downward.

Since DX'g was your goal, why not take advantage of this feature? During
summer months troposheric ducting provides some pretty amazing DX features
in this band. In the states, it is common to for stations to copy traffic
hundreds of miles away when this happens.

Best regards,

Jack Painter
Virginia Beach, Va

Ian White, G3SEK wrote:
K7MEM wrote:


There use to be a program available written by Gunter Hock, DL6WU,
that was for designing VHF/UHF yagi antennas. It took into account
boom type and size, element size, bonding methods, etc.. The original
program was written in BASIC.


There are now many different programs called "dl6wu-something.bas" out
there on the web... but DL6WU didn't actually write any of them.

The master copy of the program that Martin is using is on my 'VHF/UHF
Long Yagi Workshop' page. It was originally written by KY4Z and W6NBI,
and AFAIK it is still the only one that DL6WU has personally checked
against his original tables and graphs. For that reason it is guaranteed
to be maintained for the indefinite future.


However, the DL6WU yagis are not suitable for the OP's original request
for 5/6 elements, because these are all "long" yagis with a minimum of
10 elements.



Thank you for the corrections. I will make the necessary adjustments on
my web page to give proper credit.

I only suggested this program to show that there are programs out there
that take the factors he described into account. He could design for 10
elements and then trim back the number of directors. This will get him
in the ball park. He could then describe it to a modeling program to
see how it stacks up.

--
Martin E. Meserve