Remember that these guys were using a well chosen test range -- they
didn't have access to MIL grade range, and they used methods to take
their range into account. When you're making measurements by
substitution, the use of calibrated observation antennas doesn't matter.
And the difference between their range, and an idealized range, doesn't
matter much, thanks to their methods. It's been 15 years since I studied
their reports, but back then, I couldn't see any holes in their methods.
Note that the baseline for gain dBd was a dipole at the location of the
DUT, and I think I recall that location was chosen for uniform ground
characteristics.
Further, if you read N6BT's writing about antennas and N0AX's antenna
reviews, it's clear that both think about how vertical directivity and
mounting height interact.
As to the Moseley results -- I don't see anything in their setup that
accounts for a 6dB difference from one antenna to another. Further, note
that results for the other antennas clustered in a far more reasonable
manner. Further -- the smaller tribander was less inferior to the others
-- more like 3dB.
Another VERY important point. The design issues are maintaining vertical
and horizontal directivity over the width of the ham band in question.
That's a LOT of variables to control. To understand this, we only need
to try modeling simple Yagis in competent software. I've never taken the
effort to go beyond Dean Straw's YW.
I'm told those with the EE chops to know that Brian Beasley has taken
this to a far higher level, but his software has been unavailable for
decades. And I haven't gone into it, because my real very tall redwoods
favor high dipoles for the lower HF bands, and it took me three years
and advice from K7LXC to find a place in that dense redwood forest where
I could swing something as small as the straight 3-el SteppIR!
73, Jim K9YC
On 3/31/2026 1:04 AM, vk3od--- via TowerTalk wrote:
He used calibrated antennas to make these measurements long before N0AX and
K7LXC whose procedure did not use calibrated measuring antennas on a controlled
range.
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