[TowerTalk] Two 15m yagi stacking

[Keith Dutson]

I am planning a stack of three 5 element 20 meter Yagis.  They will be at
50, 100 and 150 feet (15.2, 30.4, 45.6 meters), close to 3/4 wavelength.
Yagi boom length often determines best stacking distance.  My Yagis have a
44 ft (13.4 m) boom.  Using a shorter boom such as found on a tri-bander,
best stacking distance should be close to 1/2 wavelength.

In my experience, more elements (spaced on a longer boom) is better than
fewer elements (on a shorter boom).  Using 4 and 5 elements is a good choice
for 40 and 20 meters, and I like 6 and 7 elements on 15 and 10 meters.  

73, Keith NM5G

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of BA7NQ Terry
Sent: Friday, February 23, 2007 7:16 PM
To: TowerTalk at contesting.com
Subject: [TowerTalk] Two 15m yagi stacking

I am preparing make my first yagi stacking for contest station and
researching some document from internet. The tower will have 30 meters high,
and I have two 5 element yagi.

My question is:

1) The separation distance between two yagi? Some documents said is 3/4
wavelength, or 5/8 wavlength, or 0.62 wavelenght. How to consider this space
vs stacking performance?

2) My idea is, the bottom yagi fix to EU, and the top yagi is rotatable,
when the top yagi beaming to EU, then switch the two yagi to "BOTH", is this
right?

3) About the YAGI, I found many station use 4 element or 5 element yagi for
stacking,  is high-elements good for stacking or just 4 or 5 elements
better?

Thanks for reading my message.

73! de BA7NQ Terry