[TowerTalk] 75 meter loop

[K4SAV]

You could move the inverted vee to 125 ft and pick up 2 to 3 dB.

A vertical loop with 102 ft horizontal wires and 42 ft vertical wires, 
with the top wire at 80 ft (resonates at 3.55 MHz), fed at the center of 
one side will give some improvement in low angle signals, about 7 dB 
improvement at 5 degrees elevation, 4.6 dB at 10 degrees elevation, 2.6 
dB at 15 degrees elevation, and the break even point is at 22 degrees.  
The inverted vee will win big time for signals above 22 degrees. No free 
lunch, sorry. The feed point impedance of this loop will be about 50 
ohms.  The bad part is that it has narrow bandwidth, about 110 KHz for 
less than 2 to 1.

If you feed this loop at the top or bottom, your inverted vee will beat 
it by about 1 dB for low angle signals.

Note: The ratio of horizontal wire length to vertical wire length is 
what makes the feedpoint impedance 50 ohms. If you make the loop square 
the feedpoint impedance goes up and you lose some low angle gain.

An inverted vee at 95 feet is a good antenna.  It' hard to beat it with 
a simple antenna without going higher.  Of course there is always the 
OB2-80.

Jerry, K4SAV

Joe Barnes wrote:

>can anyone tell me what kind of performance I can expect from a 75 meter 
>loop positioned on its side with the top at 80 feet or so? I am still 
>trying to find something to out perform my inverted v with the apex at 
>95 feet. Ive tried a bazooka at 125 feet and it was a joke. Thank yall, 
>73, Joe N4JBK
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