Out of curiosity, I brought up an EZNEC model of two stacked 5 element
beams from the ARRL Antenna Book, 20th Ed., model ARRL_5L15 95'.EZ. I
deleted half the elements to leave a single 5 element array, and lowered
it to 65 feet. I also changed the current source to a voltage source for
simplicity, and removed the wire loss (which EZNEC translates to NEC as a
bunch of loads) -- the wire loss makes a difference of only 0.05 dB.
Here's an NEC model of the 5 element array up 65':

CM 5L15 95'
CE
GW 1,11,-3.464585,-3.528538,19.812,-3.464585,3.528612,19.812,.008906
GW 2,11,-1.766258,-3.345701,19.812,-1.766258,3.3457,19.812,.0088644
GW 3,11,-.4925144,-3.283913,19.812,-.4925144,3.283913,19.812,.0089841
GW 4,11,1.120895,-2.98782,19.812,1.120895,2.98782,19.812,.0087506
GW 5,11,3.464584,-2.793987,19.812,3.464584,2.793987,19.812,.009137
GE 1
FR 0,1,0,0,21.2
GN 2,0,0,0,13.,.005
EX 0,2,6,0,1.414214,0.
RP 0,1,361,1000,80.,0.,0.,1.,0.
EN

Gain as-is is 14.11 dBi; with loss, 14.07 dBi. Zin = 21.51 - j22.26 ohms.
Takeoff angle is 10 degrees.

Seems to me this would be a lot easier to build and support than the
"Gaussian" model. And I'll bet you could make up the half dB gain
difference quite easily by adding a sixth element.

People with the 20th Edition of the Antenna Book can open the model, make
the same modifications I did, and run it with the EZNEC ARRL program
furnished with the Antenna Book, or any EZNEC program type except the
demo.

Anyone who's impressed with the gain figure of either antenna should model
a dipole at the same height for comparison.

Roy Lewallen, W7EL

A dipole at 85 ft shows a gain of 7.5 dBi, with a TOA of 11 degrees.
Using ARRL's program "YW" a 6 element Yagi at 85 ft has a gain
of 16.7 dBi on 14 MHz.

Running Roy's program, above, I get exactly the same results. The
F/B ratio is also excellent at 28 dB.

Frank

"Frank's" wrote in message
news:WW4%h.5980$au6.1475@edtnps90...
Out of curiosity, I brought up an EZNEC model of two stacked 5 element
beams from the ARRL Antenna Book, 20th Ed., model ARRL_5L15 95'.EZ. I
deleted half the elements to leave a single 5 element array, and lowered
it to 65 feet. I also changed the current source to a voltage source for
simplicity, and removed the wire loss (which EZNEC translates to NEC as a
bunch of loads) -- the wire loss makes a difference of only 0.05 dB.
Here's an NEC model of the 5 element array up 65':

CM 5L15 95'
CE
GW 1,11,-3.464585,-3.528538,19.812,-3.464585,3.528612,19.812,.008906
GW 2,11,-1.766258,-3.345701,19.812,-1.766258,3.3457,19.812,.0088644
GW 3,11,-.4925144,-3.283913,19.812,-.4925144,3.283913,19.812,.0089841
GW 4,11,1.120895,-2.98782,19.812,1.120895,2.98782,19.812,.0087506
GW 5,11,3.464584,-2.793987,19.812,3.464584,2.793987,19.812,.009137
GE 1
FR 0,1,0,0,21.2
GN 2,0,0,0,13.,.005
EX 0,2,6,0,1.414214,0.
RP 0,1,361,1000,80.,0.,0.,1.,0.
EN

Gain as-is is 14.11 dBi; with loss, 14.07 dBi. Zin = 21.51 - j22.26 ohms.
Takeoff angle is 10 degrees.

Seems to me this would be a lot easier to build and support than the
"Gaussian" model. And I'll bet you could make up the half dB gain
difference quite easily by adding a sixth element.

People with the 20th Edition of the Antenna Book can open the model, make
the same modifications I did, and run it with the EZNEC ARRL program
furnished with the Antenna Book, or any EZNEC program type except the
demo.

Anyone who's impressed with the gain figure of either antenna should
model a dipole at the same height for comparison.

Roy Lewallen, W7EL

A dipole at 85 ft shows a gain of 7.5 dBi, with a TOA of 11 degrees.
Using ARRL's program "YW" a 6 element Yagi at 85 ft has a gain
of 16.7 dBi on 14 MHz.

Running Roy's program, above, I get exactly the same results. The
F/B ratio is also excellent at 28 dB.

Frank

Is it possible to post an image of what Art's antenna would look like?
I would like to so what his antenna looks like as his discription has gone
beyound my imagination.

Jimmie.

Is it possible to post an image of what Art's antenna would look like?
I would like to so what his antenna looks like as his discription has gone
beyound my imagination.

Jimmie.

I can send you a JPEG of an NEC graphic. It is only 9 kB. The array
looks like two stacked 3 element yagis, with only the upper array
driven. I deleted the lower array, and it only made a slight
difference to the performance.

Frank

Frank's wrote:

I can send you a JPEG of an NEC graphic. It is only 9 kB. The array
looks like two stacked 3 element yagis, with only the upper array
driven. I deleted the lower array, and it only made a slight
difference to the performance.

Sure doesn't look like stacked Yagis to me. No two elements are at the
same height. Or are we talking about the same model?

Roy Lewallen, W7EL

On Sat, 05 May 2007 16:15:13 -0700, Roy Lewallen
wrote:

Sure doesn't look like stacked Yagis to me. No two elements are at the
same height.

Hi Roy,

Ever the conventionalist. Elements needn't be at the same height to
perform this job. Maybe to perform a better job, maybe not; but it
doesn't seem like anyone will visit this one again soon. Antennas
seem to have the capacity to present a better model than the last one
shown. Using the NBS Yagi to compare certainly wasn't the epitome of
design.

Or are we talking about the same model?

Only one person could possible confirm that, and history has revealed
we have NEVER seen that happen.

73's
Richard Clark, KB7QHC

"Roy Lewallen" wrote in message
...
Frank's wrote:

I can send you a JPEG of an NEC graphic. It is only 9 kB. The array
looks like two stacked 3 element yagis, with only the upper array
driven. I deleted the lower array, and it only made a slight
difference to the performance.

Sure doesn't look like stacked Yagis to me. No two elements are at the
same height. Or are we talking about the same model?

Roy Lewallen, W7EL

If I got the coordinates right, then tags 2, 4, and 6 are within +/- 2 ft of
the
same plane and parallel to the Y axis. Tag 6 is in the middle, and is the
driven element. Tag 2 is longer (Reflector) than the driven element, and
Tag 4 is
shorter (director). The currents in these 3 elements appear to be about
what
I would expect in a 3 element beam. The other three Tags (1, 3, & 5) are
more random in their placement, and far removed from the "Yagi" like plane.
The do not seem to contribute very much
to the performance. The radiation pattern is very close to a Yagi
pattern, although the vertical beam width appears wider.

Just to be sure I did not mess up -- again! -- I have pasted the code below.

Frank

CM Gaussian Array
CE
GW 1 31 273.3 164.1 820 273.3 -164.1 820 0.65
GW 2 41 25.1 203.3 1079 25.1 -203.3 1079 0.65
GW 3 31 171.1 202.1 582 171.1 -202.1 582 0.65
GW 4 30 321.6 178.4 1036.5 321.6 -178.4 1036.5 0.65
GW 5 41 2.1 206.5 701.2 2.1 -206.5 701.2 0.65
GW 6 31 153.5 194.5 1038.1 153.5 -194.5 1038.1 0.65
GS 0 0 0.025400
GE 1 -1 0
GN 2 0 0 0 13.0000 0.0050
EX 0 6 16 0 1 0
FR 0 5 0 0 14.15 0.05
LD 5 0 0 0 3.08E7
RP 0 181 1 1000 -90 0 1 1
EN

"Frank's" wrote in message
news:%V6%h.6012$au6.5029@edtnps90...
Is it possible to post an image of what Art's antenna would look like?
I would like to so what his antenna looks like as his discription has
gone beyound my imagination.

Jimmie.

I can send you a JPEG of an NEC graphic. It is only 9 kB. The array
looks like two stacked 3 element yagis, with only the upper array
driven. I deleted the lower array, and it only made a slight
difference to the performance.

Frank

If you could send me the jpg I would appreciate it. I had been trying to
picture what this may look like from Art's discription. I was imaginining a
cluster of elements of random lengths pointing in all kind of different
directions all fed from a common feedpoint.

Thanks
Jimmie