[BC] Part 15 LPAM Questions?

[Robert Meuser]

While what you wrote is absolutely true, the reactance is the key 
problem as the required loading coil will have significant resistance 
compared to the resistances you mentioned. While ground losses are also 
a problem, the resistance of a practical loading coil is the big 
sticking point.

R


Richard Fry wrote:

>> It is the extremely high reactance that is the problem.
>
> ___________
>
> The high reactance is a problem, but even when it is canceled using an 
> inductance at the feedpoint, the radiation resistance of a 3-meter 
> conductor -- when the 3 meters includes the conducting path to an r-f 
> ground buried in the earth -- is barely 1/10 of an ohm even in the 
> X-band.
>
> The r-f resistance in the ground connection of a typical Part 15 setup 
> can be tens of ohms.  Antenna system efficiency is the ratio of the 
> radiation resistance to the total of all resistances in the antenna 
> system, so even a resonant Part 15 antenna system can have 
> efficiencies of less than 1%, and many/most of the FCC-compliant ones 
> probably do.
>
> RF
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