On 4/20/2024 11:57 AM, Richard (Rick) Karlquist wrote:
> No one has commented on the "High Efficiency" "Broadband" claims,
Unfortunately, "High Efficiency" and "Broadband" are relative terms
and have a different meaning to the AM broadcasters than they do to
amateurs. They amount to nothing more than marketing terms.
To the broadcaster, "High Efficiency" simply means the same field
strength as a "standard" (typically 90 degree) antenna over the
standard 240 radial system. The HEB, given the field measurements,
meets that standard. Here one is simply trading one set of losses
for another.
Similarly, to the AM broadcaster, "Broadband" simply means sufficient
bandwidth to keep the transmitter happy and avoid distortion of an
IBOC digital signal. That is far more narrow than even a "50 KHz
under 1.5:1" for amateurs on 160.
73,
... Joe, W4TV
On 4/20/2024 11:57 AM, Richard (Rick) Karlquist wrote:
No one has commented on the "High Efficiency" "Broadband" claims, so I
will. No antenna of this size will simultaneously have both high
efficiency and wide bandwidth, according to established limits in the
literature. See K6OIK's Pacificon paper with the latest refinements
to these limits. Additionally, narrow band antennas typically don't
handle a lot of power. I doubt that this would be extensible to 50 kW.
not that it matters for ham radio.
When placed over ground, even with an elevated counterpoise, there
would still be ground losses, which would affect efficiency.
Also, although the antenna technically only occupies 1/8 acre, the
fields will be very high within 1/6 of a wavelength, about 50 meters
at 1 MHz. This covers 2 acres. I know my 90 foot 160m vertical,
complete with guys, ground screen and top loading wires neatly
fits within a 100 foot radius circle. about an acre.
What's not to like about this?
Rick N6RK
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