Building my new antennas:


In June 2008 I started the most complex antenna project since I got a ham:

The first antenna should be a full size 80m dipole. To handle lightning protection the dipole will be build in some distance from the house.

img_4588.jpg (236336 Byte) A rented skid loader helped a lot to dig grooves for the cables.
img_4586.jpg (188663 Byte) These pictures show the longest groove from the house the to antenna in about 60m distance.
img_4585.jpg (221805 Byte) Unfortunately this groove crosses our doorway. Therefore I hade to remove and later to replace the pavement which was a lot of work.
img_4595.jpg (180990 Byte) Every 10 meters I build an inspection point which makes it easier to draw the cables into the burried pipes.
img_4594.jpg (208285 Byte) In the background you can see the ground strap. This will also be the mounting point for the lightning protectors.
img_4596.jpg (242896 Byte) The other end of the pipe ends at the antenna tower. Another pipe with all cables then ends directly below the shack.
Antennas for the lower bands 80m and 40m:
for a long time I evaluated different multi band antennas, like

FD4, Trap Dipoles, Multi Band Dipoles from Kelemen or Fritzel etc.

As ideal solution I choosed a full-size 80m and a full-size 40m Dipole connected to a single 1:1 balun. With an angle of over 60 degrees the two dipoles do not effect each other in any way. The big advantage is that I can feed it over a single cable and do not need any components for tuning.

kw_ant_diag.jpg (59550 Byte) the dual band dipole was measured with the FA-NWT network tester, published in the German Funkamateur magazine.

After only 2 tries for 80m and one try for the 40 m band the antenna was tuned to the right length and worked perfectly.

The picture on the left shows the SWR on both bands.