Hustler 6BTV 6 band trap vertical antenna installation.
Few useful hints based on my experience.
One month later after I arrive in Tanzania and settle down myself along with my family I applied for Amateur Radio License and became thoughtful about antenna type to use for operating from 5H land. In fact, the roof of the house had not enough space for monumental setup and the only option was a vertical antenna. Since I was going to be active almost on all bands, the vertical might be multiband. Having some experience and access to the Russian Internet I could build any antenna. Options were so many, that I even lost my head at the beginning. But later I had to admit the defeat of this idea. It was impossible to find any simple material for antenna construction in Dar es Salaam. There was no aluminum tubing available in this city! My decision in choosing antenna type was partially based on reviews on eHam.net. Finally I decided to buy Hustler 6BTV 6-band trap vertical and I must say that I don't regret. Below are some useful and sometimes essential hints for those, who decide to install a vertical antenna and, in particular, for Hustler 6BTV users.
Hint #1: 6BTV is a great antenna, but it was designed for ideal climatic conditions.
The weather condition at Dar es Salaam city location is very heavy. Not so windy, this part of the Indian Ocean has calm WX. But almost 100% humidity and my very close location to the Ocean (moisture consists of billions of salty water drops) become deadly for aluminum constructions. I decided to protect antenna from impact of salty water and protect at least all interconnections of tubing. I remember in Larnaca, Cyprus Robert (S53R) asked me to give him a hand to pull down his 6BTV from the roof of our hotel. All interconnections were tightly welded! Unbelievable! Dust and moisture made it as hard as cement! The first thing I paid my attention on was the 80m radiator body. It is actually a coil isolated with PVC cover. Upper and lower ends of the radiator have 1-2mm of open area, which is for some reason not protected with PVC and on the whole it is not well isolated from moisture. Secondly, the upper and lower ends of traps have vertical cuts for insertion into the conjugate tubes. These cuts are too long on all traps . It also pose a threat of flowing of moisture inside the trap. It's not only my opinion, that the feeding assembly needs a serious improvement. All mentioned parts were additionally isolated using self-amalgamating rubber tape and silicone sealant, which is used for waterproof sealing in the bath and kitchen. Sealant resists mildew and withstands temperature extremes from between -50 to +150 deg. C. An excellent material for antenna home-brewers!
Antenna was assembled on the ground in two pieces. The lower part from the feeding point up to the 20m trap. And the rest of the upper antenna parts in the second piece. Final assembling was done on the roof. Erection of the antenna and fixing its guys took only 5 minutes.
Hint #2: Use UV protected material wherever possible.
I already had to replace PVC guy ropes. They become crumbly under African sun. Still have no idea what material would be the best since it must be a good isolator, strong enough and UV resistant at the same time.
Hint #3: 6BTV will never perform well without good counterpoise system. YOU MUST USE RADIALS WITH IT!
Statement saying that 6BTV will work without radials is maybe true only for ground-mounted antenna case. However, I red articles where other people suggested to make as many random length radials for ground installation for better performance.
What happen if you do elevated 6BTV installation without counterpoise system? Well, if you are lucky you may get a good SWR reading on all bands. The most common confusion is that SWR 1:1 means effective antenna performance. In reality this is not true. A dummy load also has 1:1 SWR if you measure it. But dummy load will never work as an antenna.
Conclusion: Use radials! Minimum 4 1/4 wavelength radials for each band as written in the Manual from Hustler. Less radials will significantly reduce the effectiveness of your antenna. E.g. I don't have enough space to make 4 radials for 75m, I could only make two going into opposite directions. My 6BTV does as a vertical dipole on 75m while it has excellent TX and RX results on 20, 15 and 10m.