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