Topband: End fed twin-lead top band antenna

[F3WT]

>
>> I seem to also remember another post where someone (Tom perhaps? -  
>> I don't
>> remember now) said they had talked with Orr about this  
>> configuration and he
>> later agreed that perhaps it didn't work as stated in the book.
>
> If you can hoist a wire (or that twinlead) to the height you've  
> described,
> the best way to utilize it is as a top-loaded vertical Tee. Simply  
> tie both
> sides of that feedline together at the ground and feed it against  
> radials.
> Tweak the length of the top horizontal section to bring the vertical  
> to
> resonance. That will give you something on the order of 30-35 ohms  
> at the
> feedpoint.


You may want to take advantage of your twin-lead other than just using  
it as to parallel connected fed 2 wires.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           Consider 
  it as a folded unipole vertical fed by gamma-match. -( source "  
Vertical Antenna Handbook from Paul H. Lee, N6PL).
This has the advantage to increase the  real-part of feedpoint  
impedance ( R of R+jX ) .

Here is how it should go:

At the bottom:
Tie one end of twinlead-vertical to radials common point (ground).  
Use  the other as your feed point ( fed directly with 50 Ohm coax or  
thru a capacitoras said elsewhere or L-network if not matched.

At the top ( at hight abt  20M times velocity factor of twin-lead  
equalling a quarter wave-length of 80M   ):
Tie both end of twin lead together on top . Tie to them your  
horizontal section (abt 20 meters normal wire ) to complete your  
antenna to in fact what it looks like :an inverted L as already said  
in earlier posts. It should resonate at 160M. If you disconnect that  
horizontal section, you should have a close 80M exclusive vertical. 
( as opposed to 160M where you will have some horizontal radiation  
lobes).


73
Pierre
F3WT