Marconi has a very valid point.
It is not wise to keep drilling holes in a boom. Though it might be “still oke” from a boom-strength point of view. It is not wise to keep on drilling holes. To be honest..I do not like the drilling holes solution from a manufacturer upfront.
1- No matter how you see it, it does reduce strength.
2- If the wind starts to blow, at some point there will be some much friction the holes become larger. That will give irritation regarding “extra” noises etc.
You might start thinking about some kind of “hubs” . There are quite some different solutions. I’m sure you will be happier with that. Especially if you keep up your antenna work (and you will) it is always easy to make the antenna in such a way you can always replace the “everything”.
It wouldn’t be wise to go for the same spacing’s as a yagi has. It is a different antenna. The diameter as well as the “length” is different. It would only be logical if the spacing is somewhat different.
It might be that the 6el quad can be improved…I don’t know, I do not have the “original” measurements.
What I do know…
The 17,1dBI gain expressed is not real. You should expect a 11/12 dBI from a 30 foot boom.
Just for fun: have you taken a look at the plots given?
If you take a look at the attached PNG file I have enlarged the “plots”. Oke, please believe me when I say 11 dBI is about max from that boom length, heck ill make it a 12 dBI just for fun.
Here comes the fun,
We all know gain comes from suppressing the beam width (your aim becomes more narrower)
This is expressed in the -3dB beam width figures. (please see explination radiation patterns and how to "see" them.
) for further explanation about beam width.
What it comes down to: Signal engineering is showing us a -3dB beam width in the order of 20 degrees. Nobody in this world is able to do that. Bare in mind…it would take at least a 3 times multiplication of boom length to get that !
So the antenna pattern provided is..Let’s say “less accurate”.
Besides…the FB is fun too!, in the specs they are -44 dB. However if I take a look at the antenna plots and interoperate them right it is nowhere near 40…just above 20 dB (and that’s not done with the 9meter boom length!)
And, no…I’m not against the this quad…I’m sure it works just fine.
against all those wrong figures
That might get a brain working, the SWR beamwidth.
The reason for that is the bandwidth expressed (SWR) it is almost 2 MHz wide! Opposite to what most people think Quads are not know for SWR bandwidth! The 2MHZ expressed means it is an OWA design. OWA designs are known for many positive things but not for maximum gain.
Antennas are fun!