Might be interesting to someone out there....

I built a copy of the 432 Quagi (8 elements) that appeared in the 1988
ARRL Antenna Book. It has a "claimed" gain of 13 dBi (which, if I
remember right, is 10.8 dBd).

I didn't lament over getting all the elements within 1/128" of an inch
and it came out OK. The only place I needed to deviate fairly
significantly is that I needed to move the first director about 3"
forward of the original design to get a better match. I have no idea
what this will do to the radiation pattern. As designed, mine had a
best SWR of 2:1, causing the solid state final in the Yaesu 857 to start
shutting down such that I was getting about 6 or 7 Watts out instead of
20. Moving the first director forward as noted got the SWR to 1.2:1.
Much as I would expect since a quad element at resonance is about 60
Ohms I believe. Anyhow...

Measured it on the antenna range today at our VHF group's
(http://www.nlrs.org) annual get-together. My antenna came in with a
9.6 dBd gain. I can live with that! It was only 0.3 dB below the
reference antenna, an 11 element Yagi. Seems to have a very sharp pattern!

Anybody have experience with this type antenna? I was impressed enough
to think about giving the 222 version a try...

Scott
N0EDV

On Sun, 24 Apr 2005 03:14:27 +0000, Scott
wrote:

Might be interesting to someone out there....

I built a copy of the 432 Quagi (8 elements) that appeared in the 1988
ARRL Antenna Book. It has a "claimed" gain of 13 dBi (which, if I
remember right, is 10.8 dBd).

I didn't lament over getting all the elements within 1/128" of an inch
and it came out OK. The only place I needed to deviate fairly
significantly is that I needed to move the first director about 3"
forward of the original design to get a better match. I have no idea
what this will do to the radiation pattern. As designed, mine had a
best SWR of 2:1, causing the solid state final in the Yaesu 857 to start
shutting down such that I was getting about 6 or 7 Watts out instead of
20. Moving the first director forward as noted got the SWR to 1.2:1.
Much as I would expect since a quad element at resonance is about 60
Ohms I believe. Anyhow...

Measured it on the antenna range today at our VHF group's
(http://www.nlrs.org) annual get-together. My antenna came in with a
9.6 dBd gain. I can live with that! It was only 0.3 dB below the
reference antenna, an 11 element Yagi. Seems to have a very sharp pattern!

Anybody have experience with this type antenna? I was impressed enough
to think about giving the 222 version a try...

Scott
N0EDV
Scott,
A few years back I scaled that 432 design to 440 and while I didn't
measure the gain, I found that the match wasn't bad (about 1.3:1) on
the first try - so I left it. That could have to do with the fact
that all I really scaled were the element lengths and I left the
spacing as-is. As to performance? Grand! The company radio club had
a "far and away" contest - who could hit the repeater from the
farthest distance; my straight line distance from the repeater was 106
miles (gotta love GPS) and using 5 watts I had workable voice contact.

As Tom suggests in his post, there are better designs - however, I
think that on a "dollar per dB" basis and ease of construction the
quagi is hard to beat.

Howard
KE6MAK

Scott wrote:
Might be interesting to someone out there....

I built a copy of the 432 Quagi (8 elements) that appeared in the 1988
ARRL Antenna Book. It has a "claimed" gain of 13 dBi (which, if I
remember right, is 10.8 dBd).

I didn't lament over getting all the elements within 1/128" of an inch
and it came out OK. The only place I needed to deviate fairly
significantly is that I needed to move the first director about 3"
forward of the original design to get a better match. I have no idea
what this will do to the radiation pattern. As designed, mine had a
best SWR of 2:1, causing the solid state final in the Yaesu 857 to
start shutting down such that I was getting about 6 or 7 Watts out
instead of 20. Moving the first director forward as noted got the SWR
to 1.2:1. Much as I would expect since a quad element at resonance is
about 60 Ohms I believe. Anyhow...

Good matching on a quagi depends on getting the loop length just
right... which in turn depends on using exactly the same insulated wire
as the original author. This becomes increasingly critical with
frequency, so at 432MHz .

Moving the first director, or bending the ends backward or forward in a
symmetrical V-shape, is a very common way of optimizing the impedance
matching. With most yagis it has very little effect on the gain and
forward lobe, though it may affect the F/B ratio.

Measured it on the antenna range today at our VHF group's
(http://www.nlrs.org) annual get-together. My antenna came in with a
9.6 dBd gain. I can live with that! It was only 0.3 dB below the
reference antenna, an 11 element Yagi.

Range measurements are the only way to find out if your antenna is
really delivering the claimed performance, and those seem like
reasonable numerical results.

Seems to have a very sharp pattern!

Welcome to the world of long yagis! If you think an 8-element is
"sharp", wait till you've built something really ambitious.

Anybody have experience with this type antenna? I was impressed enough
to think about giving the 222 version a try...

Quagis are OK, and easy to build, but nothing special compared to other
types of long yagi.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
VHF/UHF Long Yagi Workshop:
http://www.ifwtech.co.uk/g3sek/diy-yagi

"Scott" wrote in message
...
Might be interesting to someone out there....

I built a copy of the 432 Quagi (8 elements) that appeared in the 1988
ARRL Antenna Book. It has a "claimed" gain of 13 dBi (which, if I
remember right, is 10.8 dBd).

I didn't lament over getting all the elements within 1/128" of an inch
and it came out OK. The only place I needed to deviate fairly
significantly is that I needed to move the first director about 3"
forward of the original design to get a better match. I have no idea
what this will do to the radiation pattern. As designed, mine had a
best SWR of 2:1, causing the solid state final in the Yaesu 857 to start
shutting down such that I was getting about 6 or 7 Watts out instead of
20. Moving the first director forward as noted got the SWR to 1.2:1.
Much as I would expect since a quad element at resonance is about 60
Ohms I believe. Anyhow...

Measured it on the antenna range today at our VHF group's
(http://www.nlrs.org) annual get-together. My antenna came in with a
9.6 dBd gain. I can live with that! It was only 0.3 dB below the
reference antenna, an 11 element Yagi. Seems to have a very sharp
pattern!

Anybody have experience with this type antenna? I was impressed enough
to think about giving the 222 version a try...

Scott
N0EDV

I built a 220 version out of a piece of the gray electrical conduit (suspose
to be more UV resistant than the PVC ) , used stainless steel welding rods
for the director elements. It worked out very well for me. I compaired it
to the 11 element CC dummy load antenna and it was much beter. I then built
2 of the 440 versions and never did get the swr to where I wanted it. Think
I gave up on them and went to a K1FO type 22 element yagi.

Hi Tom,

Yes, BEAUTY!! Well, we could have been faced with that "S" word.
No, not the stuff you step in, the stuff you have to shovel. Oh, wait.
Both "S" words fit that description. I was working in Hayward on
Friday and we were having a white-out from the "S" word. Hard to
believe it was 80 just one week before Aurora.

Actually, I'm quite pleased with the Quagi. It appears they outperform
(most) Yagis (at least in gain) with equal numbers of elements. The
loop driven element also seems to help with noise pickup too. It seems
to be a quieter antenna than my Yagis. Running QRP on 432, I'll take
and radiation I can get, even if it's from the feedline (That's my
omni-direction part of my antenna so I can hear others calling and then
I can swing the antenna!!)

Scott
N0EDV


Tom Ring wrote:
Scott wrote:

snip


Measured it on the antenna range today at our VHF group's
(http://www.nlrs.org) annual get-together. My antenna came in with a
9.6 dBd gain. I can live with that! It was only 0.3 dB below the
reference antenna, an 11 element Yagi. Seems to have a very sharp
pattern!

Anybody have experience with this type antenna? I was impressed
enough to think about giving the 222 version a try...

Scott
N0EDV


Good to see you today, Scott. Finally a "nice day" for Aurora - 45
degrees, sunny, and 15 mph north winds. Much nicer than the last 2
years, eh?

I have many 432 designs that will work better than a quagi on the same
boomlength. The quagi as you made it has a significant amount of
feedline radiation, and the gain could be a lot better.

Drop me a note, and I can give you plans, including the T match. If you
dont have delron element insulators available, there are cheap
substitutes you can make from plastic wall anchors.

And 222 yagis are available also. I have K1FO yagis scaled to all bands
that are appropriate.

tom
K0TAR

Hey Ralph,

If you have access to an MFJ 259 type antenna analyzer with the 440 band
included, it makes it a piece of cake to get a match. What I did was
pull out the first director and laid it on top of the wooden boom and
moved it forward until I achieved the lowest SWR, which was 1.2:1.
Never did alter the size of the driven loop. May screw up the patter or
efficiency, but I don't have a good way to measure either, so I didn't
give much of a hoot...just wanted to make the radio happy so it pumps
out full power

Thanks for the words of encouragement...think I'll try a 222 version...

Scott
N0EDV


Ralph Mowery wrote:

"Scott" wrote in message
...

Might be interesting to someone out there....

I built a copy of the 432 Quagi (8 elements) that appeared in the 1988
ARRL Antenna Book. It has a "claimed" gain of 13 dBi (which, if I
remember right, is 10.8 dBd).

I didn't lament over getting all the elements within 1/128" of an inch
and it came out OK. The only place I needed to deviate fairly
significantly is that I needed to move the first director about 3"
forward of the original design to get a better match. I have no idea
what this will do to the radiation pattern. As designed, mine had a
best SWR of 2:1, causing the solid state final in the Yaesu 857 to start
shutting down such that I was getting about 6 or 7 Watts out instead of
20. Moving the first director forward as noted got the SWR to 1.2:1.
Much as I would expect since a quad element at resonance is about 60
Ohms I believe. Anyhow...

Measured it on the antenna range today at our VHF group's
(http://www.nlrs.org) annual get-together. My antenna came in with a
9.6 dBd gain. I can live with that! It was only 0.3 dB below the
reference antenna, an 11 element Yagi. Seems to have a very sharp

pattern!

Anybody have experience with this type antenna? I was impressed enough
to think about giving the 222 version a try...

Scott
N0EDV


I built a 220 version out of a piece of the gray electrical conduit (suspose
to be more UV resistant than the PVC ) , used stainless steel welding rods
for the director elements. It worked out very well for me. I compaired it
to the 11 element CC dummy load antenna and it was much beter. I then built
2 of the 440 versions and never did get the swr to where I wanted it. Think
I gave up on them and went to a K1FO type 22 element yagi.

Yes, I especially like the "ease of build" feature and it was very easy
to get a good solid antenna connector mounted. That always seems to be
the weak point of most homebrew antennas...the feed is usually so
flimsy, I'm afraid to throw the antenna in the back of the truck to haul
it to a portable operating site!

Scott
N0EDV

Ian White G3SEK wrote:

edited here to save bandwidth...

Quagis are OK, and easy to build, but nothing special compared to other
types of long yagi.

Amen brother! There may be better designs, but the Quagi has to be near
the top in the catecories you mentioned, and I agree with everything you
said. Besides, the proof is in the pudding...106 miles on 5 Watts!
Almost unheard of around here (Wisconsin). I'd be pleased with that for
sure!

Scott
N0EDV


Howard wrote:

On Sun, 24 Apr 2005 03:14:27 +0000, Scott
wrote:


Might be interesting to someone out there....

I built a copy of the 432 Quagi (8 elements) that appeared in the 1988
ARRL Antenna Book. It has a "claimed" gain of 13 dBi (which, if I
remember right, is 10.8 dBd).

I didn't lament over getting all the elements within 1/128" of an inch
and it came out OK. The only place I needed to deviate fairly
significantly is that I needed to move the first director about 3"
forward of the original design to get a better match. I have no idea
what this will do to the radiation pattern. As designed, mine had a
best SWR of 2:1, causing the solid state final in the Yaesu 857 to start
shutting down such that I was getting about 6 or 7 Watts out instead of
20. Moving the first director forward as noted got the SWR to 1.2:1.
Much as I would expect since a quad element at resonance is about 60
Ohms I believe. Anyhow...

Measured it on the antenna range today at our VHF group's
(http://www.nlrs.org) annual get-together. My antenna came in with a
9.6 dBd gain. I can live with that! It was only 0.3 dB below the
reference antenna, an 11 element Yagi. Seems to have a very sharp pattern!

Anybody have experience with this type antenna? I was impressed enough
to think about giving the 222 version a try...

Scott
N0EDV

Scott,
A few years back I scaled that 432 design to 440 and while I didn't
measure the gain, I found that the match wasn't bad (about 1.3:1) on
the first try - so I left it. That could have to do with the fact
that all I really scaled were the element lengths and I left the
spacing as-is. As to performance? Grand! The company radio club had
a "far and away" contest - who could hit the repeater from the
farthest distance; my straight line distance from the repeater was 106
miles (gotta love GPS) and using 5 watts I had workable voice contact.

As Tom suggests in his post, there are better designs - however, I
think that on a "dollar per dB" basis and ease of construction the
quagi is hard to beat.

Howard
KE6MAK

On Mon, 25 Apr 2005 02:47:25 +0000, Scott
wrote:

Amen brother! There may be better designs, but the Quagi has to be near
the top in the catecories you mentioned, and I agree with everything you
said. Besides, the proof is in the pudding...106 miles on 5 Watts!
Almost unheard of around here (Wisconsin). I'd be pleased with that for
sure!

Scott
N0EDV

Well, I did cheat a little bit - was up a couple thousand feet on a
mountain. If you're interested and have a good atlas or online map
service, my location is the LA area and the repeater is located pretty
darn close the intersection of the 405 and 105 freeways and I was
located close to the intersection of the 14 and 395 highways.

Now get busy and build the 222 mHz version 8-}
73,
Howard
KE6MAK


Howard wrote:

On Sun, 24 Apr 2005 03:14:27 +0000, Scott
wrote:


Might be interesting to someone out there....

I built a copy of the 432 Quagi (8 elements) that appeared in the 1988
ARRL Antenna Book. It has a "claimed" gain of 13 dBi (which, if I
remember right, is 10.8 dBd).

I didn't lament over getting all the elements within 1/128" of an inch
and it came out OK. The only place I needed to deviate fairly
significantly is that I needed to move the first director about 3"
forward of the original design to get a better match. I have no idea
what this will do to the radiation pattern. As designed, mine had a
best SWR of 2:1, causing the solid state final in the Yaesu 857 to start
shutting down such that I was getting about 6 or 7 Watts out instead of
20. Moving the first director forward as noted got the SWR to 1.2:1.
Much as I would expect since a quad element at resonance is about 60
Ohms I believe. Anyhow...

Measured it on the antenna range today at our VHF group's
(http://www.nlrs.org) annual get-together. My antenna came in with a
9.6 dBd gain. I can live with that! It was only 0.3 dB below the
reference antenna, an 11 element Yagi. Seems to have a very sharp pattern!

Anybody have experience with this type antenna? I was impressed enough
to think about giving the 222 version a try...

Scott
N0EDV

Scott,
A few years back I scaled that 432 design to 440 and while I didn't
measure the gain, I found that the match wasn't bad (about 1.3:1) on
the first try - so I left it. That could have to do with the fact
that all I really scaled were the element lengths and I left the
spacing as-is. As to performance? Grand! The company radio club had
a "far and away" contest - who could hit the repeater from the
farthest distance; my straight line distance from the repeater was 106
miles (gotta love GPS) and using 5 watts I had workable voice contact.

As Tom suggests in his post, there are better designs - however, I
think that on a "dollar per dB" basis and ease of construction the
quagi is hard to beat.

Howard
KE6MAK