2 meter beam

[ethomas]

I am going to stand my tower in a couple of weeks with a set of 4 element maco. I was thinking about putting a 2 meter beam out to the side about 4 foot even with the boom will this work or affect anything?

 

[BJ radionut]

Ethomas: Question...are you thinking of placing the 2m beam in-between a set of stacked 4's(vertical 4's)?
Or just offsetting it from main mast on a Horizontal beam?
I have had a 15 element 2m beam(vertical) as little as 4ft. above a large tri-band beam and it worked fine...did it scew the pattern of either?
(most likely) but did it really mater...no not really.
Will if affect the tuning of each after placement?...Yes I found adjustments were necessary after array was up on the tower...
So anyway give us a few more details of your plans...
All the Best
BJ

 

[ethomas]

i was thinking of offsetting it from main mast my maco 4 beam will be mounted vertically. I do not think i could put it above or below because my mast pipe would have to be way long because the elements are so long. I think to the side would not affect it much

 

[BJ radionut]

ethomas: These thoughts(maybe some else has done something like this)...The problem I see is getting the whole package balanced. The "stacking" support for the 2m beam is going to present a interesting "wind load" issue. I would think the 2m beam will have to be 3 or 4ft (just guessing) away from the 4 element to keep the interaction between them to a minimum...then to hold the 2 stable is going to require a good stable/stout thrust bearing on the top of the tower...and a rotor with a good brake...HAM IV/Tail-twister or the like to minimize the stress on the boom and rotor.

If your looking for good ground wave conditions on 10/11m with the Maco in the vertical position then standing off the 2m beam may cause the mast to stress(or lean) in the direction of the additional boom...
If your interest is working DX then the Maco would much better be served Horizontal a few feet above the top of the tower(lower noise threshold in most cases) and then mount the 2m beam /4 ft or so above/then say an AR10- 1/2 wave vertical for 10/11m above that...

I did that with a old Mosley tri-bander(10/15/20m) about 3 feet above the top of the tower...then 5ft to the boom of a pair of "stacked" 15 element 2m vertical beams...then the AR10 was only about 2 or 3 feet above the top of the 2m stack...So all total only about 11 or 12 foot of mast above the tower....
I used a $50 thrust bearing at the top...I turned the whole array with Alliance mod. 73 twin speed rotor(about $100 used) for 7 or 8 years before Hurricane "IKE" twisted the tower about 10ft from the bottom....
I am getting windy here!!!
Anyway the Mosley was at 54ft and the AR10 was around 60ft at the bottom...
The 2m stack with 25 watts I could easily work 50-100+ miles simplex...
the AR10... 100+ miles on 10m ground wave was pretty common(DX it was sometimes better than the Mosley)...
So that's my thoughts for the $.02 worth...
All the Best
BJ

 

[Captain Kilowatt]

Something else to consider is that the 2m beam offset from the mast will tend to act like a weather vane in the wind and want to turn the rotator placing a lot of stress on it.

 

[RatsoW8]

I would definately mount the 4 ele yagi horizontaly. Put up a cheap 1/4 wave gp for local stuff. Then mount the 2m yagi a few feet abouve it. This is how I set up my F12 C-3SS and 2/440 yagi above it. The F12 is at 45' and the 2/440 yagi is at about 50'. The hazer is a luxury