Topband: Suggestions for a tower?

[Jim Brown]

On 4/23/2014 5:15 AM, Jaan Jürgenson wrote:
> I could think of isolating the guy wires or replace them for non-conductive
> type. I'm not sure if it possible to isolate the base today. Shunt fed the
> tower, use it as a folded monopole? Or should I just use the tower as a
> support for a L-antenna?

Hi Jaan,

Certainly the tower without the guy wires would load and perform quite 
well, but it also needs a good radial system.

To load the tower, you would need to isolate those guy wires, and also 
break them up with egg insulators. That's a tricky thing to do safely 
with the tower already up in the air, and it means that you will have to 
REPLACE the existing guys, because they will not be long enough to 
terminate at each insulator. I would get advice from someone very 
experienced with tower work before attempting it.

Another way to use the tower effectively is as a support for a sloping 
vertical that is insulated from the tower at the top, and fed from the 
base, also with radials. The tower will act as a passive reflector, 
providing a few dB of gain in the direction of the slope. The tower also 
needs radials for this configuration. I have two sloping wires like this 
on my 120 ft tower, one going east, the other west. The feedpoints are 
roughly 18m from the tower.

You MIGHT get away with the sloping wires with the guys in place as they 
are -- I would certainly prepare and study an NEC model before trying it.

73, Jim K9YC