[Elecraft] ARRL book on receiving antennas

[Don Wilhelm]

Skip,

That is a great formula for theory - I vaguely remember it from my 
electromagnetic fields course.
But how you measure it?
With practical measurement equipment, it is difficult to isolate to a 
single plane.

That may be do-able with fully characterized equipment in a controlled 
antenna field space or in an EMC lab, but it certainly is not practical 
in a typical ham antenna installation - and even the radiation 
resistance is not easily measured.

Antenna modeling done properly will provide a much more easily produced 
result.  Comparative results between different antennas can be obtained 
from a reference pickup antenna, but that can only show the relative 
performance, we still have to guess at the efficiency.

73,
Don W3FPR

On 9/9/2018 4:26 PM, Fred Jensen wrote:
> It's the double integral of the power [watts] over all elevation angles 
> 0 to Pi and all azimuths 0 to 2Pi divided by the power [watts] 
> dissipated in the radiation resistance at the feed point.  This of 
> course assumes the antenna is over a flat, horizontal plane. ;-)
> 
> 73,
> 
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
> 
> On 9/9/2018 12:39 PM, Bob McGraw K4TAX wrote:
>> How does one measure transmit antenna efficiency?
>>
>> Bob, K4TAX