Topband: Portable 18m toploaded vertical

[Björn Mohr]

Hi gang!

Some time ago I asked for antenna ideas for the 18 meter glass fibre
Spiderbeam pole. Thanks for all the input!

Of the many ideas I have chosen to go for a top loaded vertical with three
sloping loading wires at 16.5 meter made of 1mm enamelled CU wire. I was
recommended not to go above 15 meters for the hat but we'll se if it
survives the winter, so far it seems steady :)

The antenna is very close to water in north direction (the Baltic Sea) and I
am using two elevated radials. It is resonant at 1825 and impedance is
around 25-30 ohm. 

My only challenge is that space available for guying makes the hat wires
slope more than the recommended 45 degrees. What I understand is that the
hat becomes less effective and the wires have to be longer, but will the
bigger angle have other effects and is there a lower limit to avoid?

Also I made an unun using a T-200-2 with a 19 turn bi-filiar winding using 1
mm enamelled CU wire. How much power should I expect this transformer to
handle?

More later on the performance!


73 de Björn /SM0MDG