GAP TITAN: Unterschied zwischen den Versionen

Version vom 22. November 2007, 18:58 Uhr

For many years, longer than a decade I have been experimenting with antennas. Most joy I won from the quad loop, because this antenna is so simple you can easily build it with a few meters of wire and a wooden mast. After a storm broke it some years ago I was left to think about something different. Well, I also had to finish my studies at Regensburg university and there was my relocation to Munich, so I had too little time to do anything spectacular. A simple long wire had to be sufficient.

But as with all long wire types, they won't have their resonance at the frequency you want to use, and so it started to get on my nerves. Antennas have always been a delicate issue with my parents since they didn't want their garden to look like a giant spider web with dozens of wires hanging in the sky, so wire-based antennas gradually lost their attraction.

One day I took a walk through the WWW and arrived at WIMO - the German representative of GAP. I discovered a web page about verticals. - Having read about the ground plane type before I was a little sceptical first, because GPs require massive traps in order to be good for longer wavelengths and not be too high either. Note, we have a limitation of 10 meters here. If you build up something higher than 10 meters, you need an official permission.

Very quickly the GAP TITAN caught my eye. Being a vertical antenna for all shortwave bands except 160 meters, it perfectly fits my need as a shortwave person. And there's something special about the GAP idea: GAP antennas tackle a very severe problem which occurs with all end-fed verticals. If you don't want to distribute kilometers of wire as a counterpoise in your garden soil, you will have a problem about dissipation, because most of the eradiated power will end up in the ground. Center-fed antennas like the GAP TITAN don't have this problem to such a big degree. They are far more efficient in getting all your power out on the air.

And such a center fed vertical fits quite perfectly in the vegetable patch of my mother!

1 Legal Issues

There is a law in Germany that generally permits constructions below 10 meters height if they don't exceed 10 cubic meters. So there is generally no permission process. An exception to this general rule may exist if there are some specific local rules to your neighbourhood ("Bebauungsplan"). The Bebauungsplan contains restrictions to heights, architectural styles etc. The local construction authority of your community can inform you on any restrictions that possibly apply.

In my case, the GAP (7.50 m) resides on the mounting pole (2 m) and thus the overall height is 9.50 m.

Another law requires transmitter operators to ensure that people will not be harmed by the electromagnetic radiation they cause. If PEP is below 10 watts, no further activity is required. If above 10 watts, German HAM operators need to send a detailed declaration to the Bundesnetzagentur on how they ensure that bypassers will not be harmed by their radiation. In my case I generally stay below 10 Watts, since I am convinced that most QSOs are possible with this power.

2 Setup Experiences

The assembly takes roughly 1 hour. It is rather straightforward if you closely follow the assembly instructions. WIMO also has a well-translated German version. In order to find a good location, it is recommendable to arrange the radial square counterpoise in the lawn in order to see its dimensions. Three weeks ago my dad and I built up the mounting pole on a solid concrete socket. Today (07-11-2007) we mounted the readily preassembled TITAN to the pole. The TITAN weighs about 12 kilos, and it will basically stand by itself. Yet it is better to install some guy wires in otder to protect it from damages in the next storm. I decided to buy the wiring kit from WIMO as it also contained a bracket to attach the wires to. The wires are actually black 3 mm DRACON ropes.

The only thing which is a little problematic in the assembly instructions is this: There is a little hole at the bottom of the antenna which leads the coax cable out of the lower section. It is necessary to do this richt at the beginning of the mounting. It is possible to do it at the end if you have forgotten it, but you have to unmount the entire lower section of the antenna for this purpose.

After attaching the TITAN to the mounting pole I mounted the counterpoise square and connected the coax to my rig. Great surprise: On 8 bands (10-12-15-18-20-30-40-80) the SWR was well below 1:2. Readjusting and fixing resonnance was not necessary!! - not even on 40m!

@@ Zeile 28: / Zeile 28: @@
 ==My GAP==
 [[Image:Gap_in_the_garden.jpg|400px]]
+[[Image:Gap_in_the_garden2.jpg|400px]]
 == Links ==

GAP TITAN: Unterschied zwischen den Versionen

Version vom 22. November 2007, 18:58 Uhr

Inhaltsverzeichnis

1 Legal Issues

2 Setup Experiences

3 Experiences and Tests

4 My GAP

5 Links

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