Thoughts about the DK7ZB 5 (6) band quad

I'm still looking for a good solution to build a 5 band quad. However I made some unsuccessful attempts in the past (27 years ago). The main problem is how to tune the reflector for max. gain/front-back. There are several tips that can be found on the internet, most are theoretically but in real life it almost couldn't be done. So in the end it's trail and error.

A while ago I came across the DK7ZB quad. It's quite a different design and easier to build. The drawback might be the open line that feeds the director but when using a autotuner and a 1:1 balun it could be easier to accomplish. Another option would be connecting it to the ladder line of the inverted-V through a remote switch.The specs are almost the same as any other 2 element 5 band quad.

Specs of the DK7ZB compared to a Big Signal 2BS-5B tradional quad as example:

	DK7ZB		2BS-5B
Band	Gain dBd	F/B dB	Gain dBd	F/B dB
10	6,3	30	5.19	18,6
12	6,2	14	4,9	12,6
15	5,8	17	5,1	14,4
17	5,5	21	4,6	13,5
20	5	30	4,95	13,1

I just took the 2BS-5B as example since this quad is popping up everywere on the internet these days. But there are many other manufacturers selling 2 element 5 band quads with almost the same specs. I could have picked any other one as example.

PDL2 quad used in 2008 @PE4BAS

I've seen quads that use aluminium wire as radiator, I really don't like that although without question
it is a lot lighter as insulated copper wire. The main advantage of isolated cu wire is that it is cheap and strong. The disadvantage is that it is heavy, you need a strong construction to hold it. But to make a strong construction for a quad antenna is not easy. It is expensive as well if you want to buy special fabricated glasfiber tubes.

Personally I just want to experiment to see if this quad would be interesting to have in my tower. But it shouldn't cost me too much. So, the idea is to use cheap glasfiber telescopic fishing rods and 1mm alu welding wire because of the weight. This way the antenna might be a bit flimsy but good enough to test things. If the prototype antenna is doing the job for me I can always decide to invest more money in a final version.

Previous 1993 attempt to build a quad on 11m, it didn't work well...