long boom 5 element for 11 meters?

[missouri 69]

I have heard that the longer a boom on a beam antenna the better....
so does anyone have measurements [plans] for a long boom 5 element?
I have a 31' boom 2 1/2 " dia to start with...
does any one have the optimum measurements for a 5 element or 4 element beam
I have measurements [plans] for maco beams
thanks
sam

 

[Master Chief]

Increasing the boom length for a number of given elements will also increase the gain of that antenna. In other words, a 5-element long boom antenna will have more gain than a 5-element short boom.

The consideration you need to make is the mechanical requirements necessary for the longer boom. If a 1.5" boom may have been acceptable for a short boom antenna, you may need to go to a 2" boom for the same amount of elements on a longer boom.

At some point, the boom can become too long. There is also a give-and-take on antenna parameters and you need to decide what parameter gets priority. In other words, if you optimize the antenna for GAIN, then your F/B suffers, and vice-versa.

Here is some good reading:
http://home.planet.nl/~poelm348/

The above website gives consideration to HEIGHT over the number of elements. It is interesting reading.

The ARRL Antenna Book comes with optimized versions of a 5-element 10 meter antenna and the software required to scale it down to 11 meters.