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Activated 2020-11-24 at 15.16Z

Marconi Antenna for LF/MF

Antenna work started with some modification of the existing 18 meter VersaTower, plan was to add 6 meter to the top section of the tower. Picture shows unmodified top section in the vise.
The threaded rods are gone and now there are turned plugs instead that fit inside the new steel pipes in a slightly coarser diameter!
The new steel pipes are mounted against the top part, the crossbars and bevels are cut and the welding jigs for these are ready, now only the welding of the tower part remains.
The welding is in full swing; in the picture it is my son, SA6AMV-Henrik, who helps.
The top part is almost finished, now all that remains is to weld new 20 mm threaded stainless steel rods in the lower part. There are aluminum pipes on the threaded rods to protect the threads during welding.
The finished and 6 meters longer top part is loaded on the trailer for further transport to the summer cottage where the antenna will be built.
Picture shows the tower in the finished condition, a 6 meter long aluminum pipe is mounted on the tower and above this there is a 2 meter fiberglass pipe where the crossbar is attached, total high 30 meter.
The construction of the small coil housing starts up, where coils, impedance transformer and other necessary electronics will be housed!
The construction of the coil housing floats on, now is the hammer instead of soldering iron that counts!
Coil housing ready and now starts the interior work, the picture is the impendance transformer attached to the wall with a copper bar that leads down to the ground network.
In this picture you see the copper pipe with a connected copper rail as from this central point it should run out for kilometers with wires in all directions.
The picture shows the bracket which will sit on the side of the coil housing where the antenna wires are connected. 
Here I mill a hole in an aluminum bar to the top crossbar of the antenna.
 The crossbar is complete; this part is located at the top of the tower on a 2 meter long fiberglass pipe.
In this picture you can see how the copper wires are connected to the crossbar. I use a 6 mm stainless steel bolt for this and also stainless coarse steel wire as strain relief.
The crossbar attached to the fiberglass pipe which also acts as an insulator.
The extended tower with 6 meters of aluminum pipes and fiberglass pipes mounted on the crossbar, today I use only 2 meters of fiberglass pipes, not as in the picture !!!
Now the work of building a ground network for the antenna starts, at the same time I measure the antenna with a little computer help, very nice work, but tough with all the digging!
One of many 80 cm wide aluminum discs that are buried in the antenna's earth network, this one like several others is right by the lake in the blue clay!
Here the seawater has flowed down into the hole, you can only see the coarse copper pipe that protrudes from the water. The copper wire is attached to an impregnated post with a 6 mm bolt.
With 1 km of copper wire in the earth network, it starts to look good in the computer, in the picture I measure between 472 and 479 kHz and the curve looks very good !!!
To get resonance on the 630-meter band, I use a roller coil, it takes about 33 uH to get resonance there. The antenna's natural resonance is approximately 600 kHz.
Here is the antenna isolator in place by the side of the coil housing, in the picture it has been raining, as per usual ...
So far, only 1 km of earth network and 3 aluminum discs are connected, much more work remains! Rome was not built in 1 day.
Simple sketch that shows in broad outline what the antenna looks like earlier, now since march 2024 it's like a Marconi L-antenna, see picture below!
From above, photo taken from Google Earth shows my new Marconi L-Antenna near the lake Öresjön at the summer QTH in locator JO67IK.

SM6BGP - Gunnar Ivarsson, Andra Hedakersgatan 16, SE-511 58 Kinna, Sweden
Member of SSA and SK6RUD - Radio Rud of Sweden

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