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.
|A rented skid loader helped a lot to dig grooves for the cables.|
|These pictures show the longest groove from the house the to antenna in about 60m distance.|
|Unfortunately this groove crosses our doorway. Therefore I hade to remove and later to replace the pavement which was a lot of work.|
|Every 10 meters I build an inspection point which makes it easier to draw the cables into the burried pipes.|
|In the background you can see the ground strap. This will also be the mounting point for the lightning protectors.|
|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.
|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.