[Lowfer] Loops 101

[Peter Barick]

>>> ashlockw@hotmail.com 10/07/02 12:20PM >>>
>
Peter,

According to the most thorough text book coverage I can find the AREA
is the 
controlling parameter for radiation efficiency Vs size. This means the

circle is the best radiator for a given length of wire. However, given
the 
50ft tall by 50ft diam cylinder, that many of us believe is the
controlling 
size of the loop, the 50ft square loop has more area than the 50ft diam

circle by 27% or 2.7db from a signal standpoint. However the circle has
27% 
less perimeter than the square and this amounts to a reduction in Rac
(AC 
resistance) of about 20% when ground losses are factored in. This would
be 
about +1db. The total advantage of the square over the circle would
then be 
only 1.7db.

Bill
>
-----------------------------------------------
Very good, Bill. Okay, I agree when, say, the base equals the diameter
dimension, then the square subtends the circle, hence have 27pct more
area. But in my prior thinking I was using an imaginary string loop
(fixed length) and pulling it into the various shapes, as it were. In LF
this may be the deciding issue when a fixed length of conductor is being
applied, as, only so much type-x wire.

However, oft times it is the anchor points that take precedence, that
pair of tall trees, that tower and tree, where the base and height are
fixed and the conductor is fitted to form. In such a case a large circle
is impractical, moreover, impossible.

Peter