Right. I.e., in my case since we are talking about a short 600' inv-v
antenna on 630m at 85' I get a calculated value for R(rad) of about 0.66
ohms.
If I raise this perfect antenna model to approx 1/2-wave above a perfect
ground I get ~16 ohms and at 1-wavelength above perfect ground ~17.3 ohms.
My goal is to arrive at a somewhat accurate number for EIRP to ensure I
am compliant with FCC requirements.
I think I have two choices:
1. Should I trust EZNEC and return my ground type to real, add back in
all my wire losses, and losses in my inductors etc and trust the
finished dBi gain value provided by the program?
2. Or should I or do I need to install the finished antenna at height
with all it's inductors and ohmic losses etc and try to make
measurements of the antenna voltages and currents at the feedpoint in an
attempt to calculate R(loss) ? I realize I will have to carefully take
into account the impedance transformation due to the coax feeding the
antenna since my measurements will be in the shack and not up on the
tower top.
Opinions or experiences anyone want to share?
Gedas, W8BYA
Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.
On 3/17/2019 12:23 PM, Edward Mccann wrote:
Noting that the Rr varies as a function of height above ground.
AG6CX
Sent from my iPhone
On Mar 17, 2019, at 7:38 AM, Dave Cuthbert <telegrapher9@gmail.com> wrote:
Gedas,
you are correct. The reported resistive part of the input impedance is the
short dipole is the radiation resistance.
Dave KH6AQ, formerly WX7G
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