Hi Carl,
Remember that power on 475 kHz is defined as ERP, so loss in the system
is OK if we have enough power to throw into the feedline! N6LF has been
working on this and published something in QEX last summer. It's
probably on his website.
On Mon,7/18/2016 3:49 PM, Carl Moreschi wrote:
My particular interest right now is a good antenna for the new 475 khz
band that is coming. I have a 1000 foot dipole at 50 feet and it
shows an excellent load at 475 khz. My belief is this antenna will be
more efficient even at a 20 degree takeoff angle than a 50 foot
vertical that has a very large and inefficient loading coil and radials.
Modeling is your friend, and these are very simple antennas to model.
It allows us to LEARN things rather than "believe" them. The key to
learning from a model is to plot the results if antennas you want to
compare ON THE SAME PLOT. The way to do this with NEC is to do the
design, compute the far field response, and save both horizontal and
vertical patterns. Then model the second antenna, save those patterns,
and then import the patterns from the first antenna onto the same graph.
Now you can clearly see which is better at which angles, and by how much.
73, Jim K9YC
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