[TowerTalk] One of our own...

[Joe Subich, W4TV]

 > Doesn't this apply to a delta too ?

All of this applies to a "delta" (triangular, apex up) loop.   Other
formats of vertical loops have different rules for feeding to maximize
vertical polarization ... for example a diamond (square) loop would be
fed at one of the "side" corners and a square or rectangular loop
(e.g., hung between two towers) would be fed in the center of one of
the [vertical] sides.

In most cases, (unless one has a tower more than 150 feet tall) the
loops will be somewhat "squashed" for 160 (flatter than optimum).  An
equilateral delta will be on the order of 160 feet tall; a "diamond"
will be nearly 200 feet tall.

73,

    ... Joe, W4TV


On 5/26/2016 2:23 PM, Bob K6UJ wrote:
> Joe,
>
> I am in the planning stage of trying a delta loop, apex up.
> Doesn't this apply to a delta too ?  For vertical radiation, feed 1/4 wave
> down from the top (apex)  ?
>
> Bob
> K6UJ
>
>
> On 5/26/16 9:58 AM, Joe Subich, W4TV wrote:
>>
>> On 5/26/2016 12:31 PM, Jim Thomson wrote:
>>> ## Instead of feeding in the lower corner, if you really wanted 100%
>>>  true vert radiation, then feed it part way up on one side. I believe
>>>  it had to be fed 1/3 the way up one side of the loop. Then route
>>> the coax straight across from the elevated feedpoint....to the
>>> tower, then down the tower to shack.
>>
>> That depends on the aspect ratio of the loop.  The correct feed point
>> for maximum vertical polarization is 1/4 wave down from the apex. If
>> you have a true equilateral triangle, the feedpoint will be 1/3 of the
>> way up from the corner ... if the loop is "flatter" (lower tower) the
>> feedpoint will be farther from the corner.
>>
>> 73,
>>
>>    ... Joe, W4TV
>>
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>>
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