[Antennaware] Equivalency.

Terry Conboy n6ry at arrl.net
Fri Feb 27 11:42:40 PST 2009

On 2009-02-26 7:45 PM, bumerang boom wrote:
> When attempting to equivalate the triangle tapered tower body to a cylindrical structure, is not enough just to find the equivalent surfaces.
> One has to consider also the fact that the cylindrical structure presents always  half of the surface to the incoming wave front while the triangle will not do this. This is to say that the illumination surface of your cylindrical sensor is always 1/2 while on the triangle is always less than 1/2 with worst case of 1/3 depending on the angle of the incident wave.
> For transmitters this might not be important but on receive it will reduce the uV/m output by a corresponding amount.
> BB
> Without Wax
The consideration of orientation may be a concern where the diameter of 
the cylinder or the face of the tower approaches a half-wavelength.  
It's unlikely to have any impact on the MF or HF bands for normal tower 
heights and vertical polarization.

Do you not believe in reciprocity?  Why would it make any difference on 
TX vs. RX?  Do you predict that doubling the diameter would double the 
received signal?

73, Terry N6RY

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