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Old October 3rd 03, 03:39 AM
Cecil Moore
 
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Greg Queen wrote:
I am no expert on the "legalese", but it appears the FCC has specified power
in terms of Effective Radiated Power (ERP). The standard is no more than
50-watts radiated by a dipole in free space. My interpretation is that you
look at the performance of your antenna at its maximum radiation point
(i.e., the azimuth & elevation) and compare it to the radiation from a
dipole in free space at its maximum radiation point(s). If your antenna has
less radiated power than the dipole, then you can feed more power to the
antenna (up to the point that you get the same radiation as a dipole in free
space).


But a horizontal dipole over ground has a gain over a dipole in free space.
Consider a horizontal dipole with a maximum gain of 6 dBi Vs a free space
dipole with a maximum gain of 2.14 dBi. Do you have to decrease the power
to the horizontal dipole over ground to bring it down to 2.14 dBi?

Consider a vertical dipole with a maximum gain of 0 dBi. Can the power
be increased to obtain the free space 2.14 dBi or 6 dBi over ground?
--
73, Cecil http://www.qsl.net/w5dxp



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Old October 3rd 03, 02:42 PM
K7JEB
 
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Greg Queen wrote:
I am no expert on the "legalese", but it appears
the FCC has specified power in terms of Effective
Radiated Power (ERP). The standard is no more than
50-watts radiated by a dipole in free space.


% Bonnie KQ6XA (in a slightly different thread):
% Roy, the FCC has clarified this issue recently
% in communications with ARRL. The FCC indicated
% we should do all our compliance calculations
% for 5MHz as if the antennas are in free space.

Cecil, W5DXP:
Consider a vertical dipole with a maximum gain of
0 dBi. Can the power be increased to obtain the
free space 2.14 dBi or 6 dBi over ground?


Don't ask.
Don't tell.
Don't pursue.

K7JEB


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Old October 3rd 03, 05:24 PM
Cecil Moore
 
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K7JEB wrote:
Don't ask. Don't tell. Don't pursue.


Darn, I was about to lay down a perfect ground for my dipole
but EZNEC says that would only gain me 1.5 dB over normal
ground.

Wonder how many 5 MHz hams have already violated the FCC
guidelines by running 50 watts into a dipole over ground?
Oops, that's asking and pursuing, isn't it?
--
73, Cecil, W5DXP

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