Tuesday, January 11, 2011

N4LA Antenna Repair

This past weekend I spent  most of my Saturday repairing my ... 4 element ... 40 meter ... wire yagi
Above is a picture of the 40 meter driven element
I also have two directors, and one reflector in this wire array 
It's pointing approximately 35 degrees NE 
Although its not quite a flat top ...its darn close ... and works very well  pointing into Europe
This is the 3rd low band season its been utilized ... and each year I've tried to make minor improvements
This year I changed the spacing of the reflector and driven element
That alone improved the front to back at least 6db / 1 S unit
I also replaced all the rope that holds the ends of the wire elements up with ... .095 Weed Eater string !!
This is an old trick a friend of mine (Dave / NA4L ) from SW Virginia showed me a few years ago.
He used this stuff to hold up the wire verticals to his 80 meter 4 square.
Some of the Europeans call it Weed Whacker String !!
Its quite a bit stronger than the small rope I was using.
It's UV resistant ... it doesn't fray like rope does up in the tree tops
It slides over the tree limbs much easier than rope... so less snags
Its almost invisible ... and, it last a long time
Best of all ... its about half the price of the rope I typically use on antenna projects 
I also use springs on the center supports that hold up the middle of each dipole element
The spring allows movement of the dipoles ... which helps strengthen the yagi in high winds.
These small improvements should decrease my maintenance time 
and increase my operating time !!


VE3WDM said...

Good morning Todd, the spring is a great idea never seen that before but sure does make sense for allowing movement in the antenna system.

John AE5X said...

I just did the same thing yesterday. I'd been meaning to for a while for all the reasons you mentioned. A spring and 2 carabiners for quick disconnect during high winds.

Anonymous said...

Thanks for an idea, you sparked at thought from a angle I hadn’t given thoguht to yet. Now lets see if I can do something with it.