The RED GUM TREE ANTENNA

[BillC]

It being a very nice April day I found time to construct a Red Gum Antenna. The details as follows... select a tall tree out in the open, take a large screw around 8'' long and drive the screw into the tree about 1'' you could use a 1/4' whitworth bolt, this fitting should be placed about 6 feet off the ground, then take a heavy duty jumper lead and connect the screw fitting from the tree to your radio using that lead . You will hear stations you have never heard before . The antenna works very well on all of the hf bands for receiving at least . I Know that some members have wire antennas in secret locations, but that might not be necessary as Red Gum trees can be found in abundance.

 

[BillC]

Red Gum trees like to drop limbs too, so you have to be careful.

 

[VK3YNV]

Interesting idea, it would be fascinating to see a frequency sweep, and maybe you could adjust the feed point impedance by moving higher up the tree away from the grounded root system.

 

[BillC]

It is amazing how well this system works, as you say Ray I,m sure the impedance would change with a different tapping point. The tree shown in the image is about 130 feet high, so a tapping point in the range of 6 to 20 feet might make a reasonable match to most receivers. This afternoon at about 4 o, clock I was able to hear lots of northern Europe stations , one I recorded from The Netherlands, a good strong signal.

 

[VK3ZYZ]

The top loading may help for the low end of the band.

 

[BillC]

Yes Denys, I am sure you are right. The tree antenna seems to work like a capacitance loaded vertical. In this particular case the tree height is about two wavelengths on 20 meters , also given that the tree trunk is around 8 to 9 feet in diameter it should perform well as a broad band device and I would suspect that impedance matching may not be particularly critical for this particular system. It really performs very well and I hope that other members would try this out for themselves. If a Red Gum tree was not available maybe an Oak tree would work. Thanks very much for the constructive comments and encouragement. Cheers...