[TowerTalk] Design of the TH-11

[Dennis W0JX]

Mike,
The Super Thunderbird is the TH-11DX and it was designed in the late 80's/early 90's by Roger Cox, WD0DGF, while he was at Telex HyGain in Lincoln, Nebraska. He explained that the design was done on an early computer and the data was sent by telephone to a computer in St. Louis, MO for processing. Antenna design was fairly crude by today's standards. 
 
The HyGain antenna line was purchased by MFJ in 1999. However, there have been NO design changes to the antenna since it was first designed by Roger. In fact, the current online manual that MFJ provides is an exact copy of my original Telex HyGain assembly manual (except for the pages which have the MFJ contact info.
 
My TH-11 was manufactured in late 1995 (the shipping carton says 6/95) and it is an original Telex product. I purchased it unused from a Michigan ham in 2005. It sat unassembled in the box until November, 2011 when I finally got the resources together to afford a crane and assembly team to remove my TH6DX from my 80 foot tower and replace it with the TH11DX.
 
A close study of my original manual, and the current MFJ/HyGain manual demonstrates that ALL of the antenna parts were taken from the TH6 and TH7 line of antennas. The boom, traps, boom to element clamps, and most of the element pieces are exactly the same! Only the wires connecting the driven elements and the balun are different plus different element lengths and spacing. To my knowledge, there is no NEC or EZNEC computer model available for the TH-11. However, I can tell you that it is big and heavy, and the stated 12.5 sq. wind area is a realistic figure.
 
Good luck with your project.
 
Dennis W0JX/8
Milan, OH