[Towertalk] 40 meter beam

[Tom Rauch]

> I suggest the same Telrex antenna OR if you can find a DX Engineering
> 3 element yagi .... GREAT antenna !

I am the happy owner of a Telrex 40M yagi (the longer boom 
antenna), now that I have rebuilt and retuned it. In original form that 
antenna is what I consider over-rated junk. I spent more on repairs 
than it would have cost to buy a new M2 antenna.

While it is big and heavy, I think the reputation mostly comes 
because it was the only big 40 meter antenna around for a long 
time. Unfortunately big and heavy is not always strong or reliable.
  
Mechanically the Telrex antenna is poorly designed. It uses thin 
tubing for the elements, and puts the elements right through the 
boom were they wobble and wear on the boom and the insulators. 

In original form, it broke something during every wind storm. 
Usually it would break right where the 1-1/2" tubing tapered to 1-
1/4".

Electrically it was a bit off from optimum, and the factory balun was 
a **very** poor design. It was severely unbalanced, and added 
reactance to the system.

I replaced the factory balun with a good balun that actually works, 
rebuilt the elements with 6061-T6 .058 wall with a better taper, and 
strutted the elements with a support line. Now it has been up a 
year or more without failures.
73, Tom W8JI
W8JI@contesting.com