|Array Solutions' W9AD 2 element multi-band vertical phasing system|
I had one Butternut HF9V for low bands and found info about WX0B Array Solutions' multi-band vertical phasing system. I contacted Jay WX0B and Bob W5OV and ordered one setup from them. Purchased one HF9V more from Europe and a lot of cables from Finland.
Whole project was very interesting. I have now about 30 radials in both verticals, which is about minimum amount, have to cut some more later. I tried to be as precise as possible with all the measurements. I didn't do any modelling with Eznec but all the documents available in Array Solutions' website, in ON4UN's Low band dxing, N0AH's article in NCJ Mar/Apr 2006 and some other articles give you a very good picture how to do it and what can be achieved. There is so many moving parts, so many changing details (terrain, ground conductivity, multi-band verticals, phasing lines, different spacings between two verticals etc) in this setup that you could spend five years with modelling if you like to and then make your PhD Thesis about this. But another way is: learn basic principles and just make it. I did. And system works fb. Thanks Array Solutions, tnx Bob, tnx Jay.
I calculated those six phasing lines for the coaxial phase shifter. My goal was to make system usable for 80-40-30 and maybe for 160 in the future. I chose those phasing lines in a way which gives at least two or usually three different phasing alternatives in all bands (160-80-40-30). This means for example on 80m that I have possibilities to use 3/8 WL (135 degrees), 1/4 WL (90 degrees) and (68 degrees) long phasing lines. All those give me different patterns. Just check Low band dxing, chapter 11 "Phased Arrays", Figure 11-2 on page 11-3. MS Excel spreadsheet is a good tool for calculations if you like to be analytical.
For 160 meters I use only another vertical's radials as a ground for INV-L. These switching boxes give you possibilities to choose only vertical A, only vertical B, A+B for a broadside pattern, A+B with 180 degrees phase shifter for an endfire pattern, A+B with delay line for an endfire towards vertical B and A+B with delay line AND with 180 degrees phase shifter for an endfire towards vertical A. Sounds complicated, but it is easy in practice. So basically an omni-directional pattern plus four different patterns per band. Plus some fine tuning with different lengths of phasing lines.
How it works ? It works very fine. The difference is not so dramatic as for example between a low mounted yagi and a vertical on 20 meters, many times with a yagi you can hear and with a vertical you can’t. Difference between one vertical and double verticals is naturally smaller. This system is not like a yagi on 40 meters, in some cases it could be worse than a dipole at 100ft high on 40m (I don't have yagis on low bands and no high trees around). But this is much better than one vertical on 80-40-30m. Not much gain compared to one vertical, in theory 2-4 dbs, in practise you will see more than this often in your s-meter and get bigger difference reports from other stations, like 1 s-unit or "10 dbs". But sometimes no additional gain or difference is very small. But patterns are there and they are just like in the papers. You get front to side and front to back attenuation between 10-30 dbs. Some deep nulls could be even deeper. Effects change in different situations (propagation, angle of radiation, band, qsb, distance to other station etc) but you turn the pattern with your switches and you will hear the difference. My vertical setup is not 100% ready, I have some things which I like to test more, I don't have enough space in my small suburban site to make everything placed like I'd like to and there is even some wires too close to these verticals and so on. But after all, this system, Array Solutions' W9AD multi-band vertical phasing system works just like it should work and has surpassed all my expectations. Very good, recommended.
73 Ari OH6MW