My ARRL books go back a decade or more
and the graph showing gain per boom length
has several curves based on different measurements
e.t.c. Has a graph been made based solely on NEC
program findings over say a perfect ground and at a uniform height?
Art

Hi Art,

While this was the common theory many years ago, there other ways to get
gain from an antenna other than boom length and number of elements.

ie On 2m we are able to get 11.2 dBd on a 45inch boom with 3 elements
stacked 2 wide. Yes, this is range tested see results at
http://www.csvhfs.org/ant/CSANT04.HTML


73,
Guenther VE3CVS
www.degendesigns.com


" wrote in message
news:xOzcd.263953$D%.243703@attbi_s51...
My ARRL books go back a decade or more
and the graph showing gain per boom length
has several curves based on different measurements
e.t.c. Has a graph been made based solely on NEC
program findings over say a perfect ground and at a uniform height?
Art

On Sun, 17 Oct 2004 17:01:22 -0400, "G&R" makes a claim and opens
himself up to skewering:

|Hi Art,
|
|While this was the common theory many years ago, there other ways to get
|gain from an antenna other than boom length and number of elements.
|
|ie On 2m we are able to get 11.2 dBd on a 45inch boom with 3 elements
|stacked 2 wide. Yes, this is range tested see results at
|http://www.csvhfs.org/ant/CSANT04.HTML

Uh Oh! The measured data show 11.2 dBd, the advertising shows 13.97
dBd. I thought maybe I went to the Raibeam site by mistake but no, I
went he

http://www.degendesigns.com/StackedVwave.htm

I love that precision BTW. I've done a fair amount of antenna range
testing using HP 8510s for measurement receivers and I've never been
able to establish gain within 1/100 dB.

But you can do it with a ham receiver and "subjective analysis".
Congratulations.

Since you're using two 45" booms spaced 58" apart, I would argue that
you should compare your design to a 148" boom Yagi and see what
happens.

How about posting your dimensions so we can see what modeling says
about them.

One further note: The Dataq DI-194 mentioned at:

http://www.degendesigns.com/Downloads.htm

WILL NOT work with all computers. This device is powered by the
serial port and my Toshiba laptops will not drive it.

Wes,
You make the point quite well that I was trying to make before I read your
post (written simultainiously)
and at the present time NEC is seen as judge absolute.
Yes there are many ways to increase gain but you cannot use a shackled NEC
program to authenticate
the results and we often use such as a crutch.
On the subject of boom length
I was basing things on a single boom length where number, position and
physical atributes of additionion elements
are brought into play to overcome program idequacies and provide correction
of assigned dimensions to achieve maximum gain.(Is this to much to ask now
that we have the NEC tool/)
To often the accusation comes up that computor input was incorrect or not
enough segments provided e.t.c.
and a datum curve would prove a valuable tool, not only to those that use
computor modelling but also
to experimentors who seek real world answers and possibly challenge the
authenticicity of either methods
Thanks for the links,will read them later, have to get a floooooo shot now
Art


"Wes Stewart" wrote in message
...
On Sun, 17 Oct 2004 17:01:22 -0400, "G&R" makes a claim and opens
himself up to skewering:

|Hi Art,
|
|While this was the common theory many years ago, there other ways to get
|gain from an antenna other than boom length and number of elements.
|
|ie On 2m we are able to get 11.2 dBd on a 45inch boom with 3 elements
|stacked 2 wide. Yes, this is range tested see results at
|http://www.csvhfs.org/ant/CSANT04.HTML

Uh Oh! The measured data show 11.2 dBd, the advertising shows 13.97
dBd. I thought maybe I went to the Raibeam site by mistake but no, I
went he

http://www.degendesigns.com/StackedVwave.htm

I love that precision BTW. I've done a fair amount of antenna range
testing using HP 8510s for measurement receivers and I've never been
able to establish gain within 1/100 dB.

But you can do it with a ham receiver and "subjective analysis".
Congratulations.

Since you're using two 45" booms spaced 58" apart, I would argue that
you should compare your design to a 148" boom Yagi and see what
happens.

How about posting your dimensions so we can see what modeling says
about them.

One further note: The Dataq DI-194 mentioned at:

http://www.degendesigns.com/Downloads.htm

WILL NOT work with all computers. This device is powered by the
serial port and my Toshiba laptops will not drive it.

Hi Wes,

Yes I am aware of the difference between the advertising on the site and the
range results.

As you are aware antennas do not have even gain across the entire band. We
have designed the antenna to cover the entire 2m band and as a result do see
a variation in the perfromance across the band, hence max gain.

And before you cut down my comments, the precision on the results are from
the softare and we are in the process of redesigning the format to more
accurately reflect our actual results both modelled and actual.
Unfortunately our business is antennas and web design.

The results posted on the CSVHF society are valid as the antenna was tested
with a gain of 11.2dBd at 144.18MHz Horiz Polarization. Design Freq is
146.0MHz.

We are in the business of designing and selling antennas not developing
antennas and giving them away for free. However, if your serious about the
data for the antenna contact me directly so that we can discuss the details
(email listed below).

As to the DATAQ, well I have no answer for that one, as we don't build it or
sell it. Our software is designed to with run it. Strange though, my
Toshiba does and so does my SONY through a USB to SERIAL converter.

One final point, the purpose of the posting was that identify that an
antenna does not always need boom length and elements for gain and that
there are other ways to achieve this.

Respectfully,

Guenther VE3CVS

www.degendesigns.com






"Wes Stewart" wrote in message
...
On Sun, 17 Oct 2004 17:01:22 -0400, "G&R" makes a claim and opens
himself up to skewering:

|Hi Art,
|
|While this was the common theory many years ago, there other ways to get
|gain from an antenna other than boom length and number of elements.
|
|ie On 2m we are able to get 11.2 dBd on a 45inch boom with 3 elements
|stacked 2 wide. Yes, this is range tested see results at
|http://www.csvhfs.org/ant/CSANT04.HTML

Uh Oh! The measured data show 11.2 dBd, the advertising shows 13.97
dBd. I thought maybe I went to the Raibeam site by mistake but no, I
went he

http://www.degendesigns.com/StackedVwave.htm

I love that precision BTW. I've done a fair amount of antenna range
testing using HP 8510s for measurement receivers and I've never been
able to establish gain within 1/100 dB.

But you can do it with a ham receiver and "subjective analysis".
Congratulations.

Since you're using two 45" booms spaced 58" apart, I would argue that
you should compare your design to a 148" boom Yagi and see what
happens.

How about posting your dimensions so we can see what modeling says
about them.

One further note: The Dataq DI-194 mentioned at:

http://www.degendesigns.com/Downloads.htm

WILL NOT work with all computers. This device is powered by the
serial port and my Toshiba laptops will not drive it.

On Tue, 19 Oct 2004 14:02:18 -0400, "G&R" wrote:

|Hi Wes,
|
|Yes I am aware of the difference between the advertising on the site and the
|range results.

So are you going to fix it or not?
|
|As you are aware antennas do not have even gain across the entire band. We
|have designed the antenna to cover the entire 2m band and as a result do see
|a variation in the perfromance across the band, hence max gain.

Huh? So are you saying that you have nearly 3 dB gain variation in 2
MHz.?

|
|And before you cut down my comments, the precision on the results are from
|the softare and we are in the process of redesigning the format to more
|accurately reflect our actual results both modelled and actual.
|Unfortunately our business is antennas and web design.

In a paper I wrote for the ARRL Antenna Compendium, I said,
"Simplified 'antenna analyzers', especially those with digital
readouts can lull the user into unjustified confidence in the accuracy
of his measurements."

Change the words "antenna analyzers" to "computer software" and it
describes this situation to a T.

|
|The results posted on the CSVHF society are valid as the antenna was tested
|with a gain of 11.2dBd at 144.18MHz Horiz Polarization. Design Freq is
|146.0MHz.
|
|We are in the business of designing and selling antennas not developing
|antennas and giving them away for free. However, if your serious about the
|data for the antenna contact me directly so that we can discuss the details
|(email listed below).

My slightly distorted email is above. If you choose to send me your
parameters, I promise to keep it in confidence. I don't not design,
or manufacture antennas (or anything else) for a living.
|
|As to the DATAQ, well I have no answer for that one, as we don't build it or
|sell it. Our software is designed to with run it. Strange though, my
|Toshiba does and so does my SONY through a USB to SERIAL converter.

I know you don't build or sell it, I'm just offering a caution to
those who might be tempted to buy one. It works on my desktop but not
my laptop, which is a pity because I had a portable use in mind.

|
|One final point, the purpose of the posting was that identify that an
|antenna does not always need boom length and elements for gain and that
|there are other ways to achieve this.

Absolutely. One driven element at the focus of a 40' parabola is a
decent antenna at 2-meters.

Regards,

Wes N7WS

" wrote in message
news:xOzcd.263953$D%.243703@attbi_s51...
My ARRL books go back a decade or more
and the graph showing gain per boom length
has several curves based on different measurements
e.t.c. Has a graph been made based solely on NEC
program findings over say a perfect ground and at a uniform height?
Art


They probably have been done but there will not be much difference between
them and the ARRL graphs. Its been long known how to calculate antenna gain,
computers just take the teadous labor out of it.

Jimmy,
I did not want to choose a curve that matches my modelling which you can
when presented with three different curves all of which are formulated at
different
times by different people. I would have thought that the advent of NEC
would
render these curves redundant !
Art

"Jimmie" wrote in message
. com...

" wrote in
message
news:xOzcd.263953$D%.243703@attbi_s51...
My ARRL books go back a decade or more
and the graph showing gain per boom length
has several curves based on different measurements
e.t.c. Has a graph been made based solely on NEC
program findings over say a perfect ground and at a uniform height?
Art


They probably have been done but there will not be much difference between
them and the ARRL graphs. Its been long known how to calculate antenna
gain,
computers just take the teadous labor out of it.

Art Unwin wrote:
"Has a graph been made based solely on NEC program findings over say a
perfect ground and at a uniform height?"

I don`t know, but I`ve seen Yagi-Uda gain versus boomlength charts.

Before relying on such charts, it may be worthwhile to read "The
Yagi-Uda Story" on page 246 of the 3rd edition of Kraus` "Antennas".

Also, the solution to a Deutsche Welle Short Wave Antenna problem on
page 703 is given on page 705:

"the gain of a single 1/2-wave dipole is 2.15 dBi and of 2 collinear
in=phase 1/2-wave dipoles is 3.8 dBi. The array of 8 such collinear
dipoles adds 3+3+3=9 dB. The reflector screen adds 3 more and the ground
bounce another 6 dB for a total gain of 3.8+9+3+6=21.8 dBi or a
directivity of 151 approx."

The solved problem is worth the price of the book as a reality check.

Best regards, Richard Harrison, KB5WZI

"Richard Harrison" wrote in message
...
Art Unwin wrote:
"Has a graph been made based solely on NEC program findings over say a
perfect ground and at a uniform height?"

I don`t know,

Neither do I thus the question

but I`ve seen Yagi-Uda gain versus boomlength charts.

So have I but not based on NEC


Before relying on such charts, it may be worthwhile to read "The
Yagi-Uda Story" on page 246 of the 3rd edition of Kraus` "Antennas".

Also, the solution to a Deutsche Welle Short Wave Antenna problem on
page 703 is given on page 705:

"the gain of a single 1/2-wave dipole is 2.15 dBi and of 2 collinear
in=phase 1/2-wave dipoles is 3.8 dBi. The array of 8 such collinear
dipoles adds 3+3+3=9 dB. The reflector screen adds 3 more and the ground
bounce another 6 dB for a total gain of 3.8+9+3+6=21.8 dBi or a
directivity of 151 approx."

The above extract is lost on me as I was looking for maximum gain per unit
boom length based on NEC without regard to number of elements
required to attain that gain. Thus increases or decreases from critical
coupling
can be ascertained..

Art


The solved problem is worth the price of the book as a reality check.

Best regards, Richard Harrison, KB5WZI