[Elecraft] KPA500 troubles

[Wes (N7WS)]

Then I guess I could just "vaguely" follow the rules, sort of like the 
President, his cabinet, the heads of the alphabet soup agencies, IRS, EPA, FBI, 
NSA, VA, ICE, DHS,... do.

That said, I think you're making this too complicated.  The rule states:

    "For the purpose of computing ERP, the transmitter PEP will be multiplied by
    the antenna gain relative to a half-wave dipole antenna. A half-wave dipole
    antenna will be presumed to have a gain of 1 (0 dBd). Licensees using other
    antennas must maintain in their station records either the antenna
    manufacturer's data on the antenna gain or calculations of the antenna gain."


Note, there is no mention of any directivity, or lack thereof, so I would take 
it that this is a theoretical free-space value.  Zero dBd is equal to 2.15 dBi 
so modelling another antenna and calculating its gain in dBi, which is the 
normal modelling outcome, then subtracting 2.15 from that number yields the gain 
relative to an ideal dipole, i.e the FCC reference.

Right away this gives a significant advantage to an actual horizontal dipole 
that has ground gain, assuming that the dipole is rotatable and the elevation 
angle is favorable for the path. Absent that, and considering the physical size 
one would probably use a vertical and bump up the power to account for the 
inevitable losses.

Wes  N7WS


On 11/12/2015 3:12 PM, Jim Brown wrote:
> Your point is, of course, well taken, Wes. BUT -- there's a certain vagueness 
> to the FCC definition, in that it does not specify mounting height of the 
> reference dipole, making comparisons to a vertical antenna, which relates to 
> mounting height quite differently, at least a bit squishy.
>
> 73, Jim K9YC
>