Quad is not a Monster
Why a Quad ?? Why not a Yagi or a Deltaloop or a ......
The simple reason is that I wanted to experience it by myself. I have been designing, constructing & working with yagis for the last 5 years of my ham radio life. A good example is the 3 el monobander yagi for 20m and 4 el monobander yagis for 10m & 15m.
Yagis are ;
Perfect. Gives what you expect and easy to handle.. cheaper to construct.. easy to tune..mechanically stable...and many more..
But, there was a dream from the start in me to construct a quad which I thought was a 'Monster'.
Monsters don't give you much more than you expect. I realized this only after building one Quad on my own efforts.
Quad is a ;
Huge antenna.. difficult to construct, handle and mount, even more difficult to tune. But once you overcome all these, it will be a better one among others. My quad is a diamond shape 2 el 5 band system. Gamma matched each element is switched through a relay box. Single feeder comes to the shack.
Construction
The construction of the quad took nearly 3 weeks. Two elements were made on the roof. This original design is a 3 el 5 band quad. But I decided to go for only Ref- Driven configuration completely ignoring the director. Yes, this is a violation of design rules but not for ever, because the 3rd element is under construction.
The initial thing was to clear some space to put this up. I had to remove my 2 monobanders for 10m & 15m from the tower.
Then I have put the 2x2 square Aluminium boom on the tower and connected the Reflector after lot of efforts during the Noon @ 30C temp. Thanks to Kapila and the team for the help . Getting the quad element to the boom is much more difficult than getting a 4 el yagi to the tower top !!
When I finished putting up the driven element also, the diamond quad looked like this (below); No feeding system /Matching system connected. The Bamboos were not treated or coated. Simple reason was to minimize the cost of construction. The antenna in the background is my 20m full size 3 el monobander which is there for the last 4 1/2 years. The diamond quad spreader arm comes closer to the roof making the life easier for tuning.
Then came the hardest part..installing the gamma matches for each element and tuning. This took nearly 2 weeks to get a satisfactory tuning.
The Bamboo spreaders are sagging and bending when they get dried under tension. That doesn't make a big impact on the antenna performnce. Then the antenna with completed gamma boxes looked like this below;
The 2 el Quad. Behind is the 20m home designed, homebrew full size yagi on 40ft tower.
The Gamma capacitor is in a homebrew PVC water pipe container. the spreaders are all Bamboo. Elements are 18 SWG copper wire. Rotator is a TV type 'Channal Master' rotor. As you can see, the boom is waiting for the 3rd element to come .
The Date 17th December 1999- 8 days before my 26th b'day. I have installed the 3rd element. This time the director and the driven element was constructed using sectioned Aluminium tubing . It looks great like it looks in the book. Now the reflector is the only element having bamboo spreaders. I might have to change it too. But I left it to the future . A special note of thanks to all my village friends who came for erecting the big baby quad.
The dimensions
x : Side length of each element (Total length is 4 times the side length)
y : Distance from the centre of spreaders to the 'element to spreader' attaching point.
