[TowerTalk] TH-6 vs. TH-7 vs. TA-36

[Bob Perring]

So far, and I understand I am jumping ahead a bit, since there may be
some who have not had a chance to respond to the question(s),the
responses about 

the Hy-Gain TH-6 vs. the Hy-Gain TH-7 

seem to centered upon the available band width for low SWR.


This was a given at the time of the question.

The TH-7 is dual element driven, so the SWR bandwidth will be better than
the TH-6 or TA-36.


OK, so I take, and easily add,  another driven element and properly
parallel feed it on the TA-36 or TH-6,

Does this move us back to a cancellation of the TH-7 being advantageous
over the other two because of SWR bandwidth ?


Does the TH-7 have "other" advantages over the TH-6 or TA-36?


So as to better focus the question,

For a tri-band beam of six element construction................


The FIXED values in the antenna comparison would seem to be:

(discounting the count of a second driven element)

A.    3 trapped elements.

B.    3 full size elements

C.    24' Boom


The VARIABLES would seem to be:

(discounting construction strength, since I am interested in performance
as the sole evaluation criteria) 

A.     Feed system

B.    Trap efficiency and Trap resonance frequencies

C.    Trapped element resonance values

D.    Full size element resonance values

E.     Element placement locations on the boom

F.     Single element "Q" values

G.     Trapped element "Q" values


Question #1

Are there parameter variables other than the above listed? 

If so, what might these be?


Question #2

What would one do to make these three antennas all equal in performance, 

or, more importantly, better in performance?


1.   Change the location of certain elements on the boom?

2.   Change the length of certain full size elements?

3.   Change certain trap resonance values?

4.   Change loaded element resonance values or post-trap or pre-trap
element 

       stub lengths?

5.    Add another driven element in parallel with the first, allowing for
feed 

       impedance alteration?


73,

Bob

N5RP

Houston, Texas 

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