It would interesting to take a known good antenna like a monoband Yagi
(or perhaps a SteppIR) and do a set of measurements over the course of
several days to evaluate the measurement repeatability. If someone had
designs on doing a K7LXC/N0AX type antenna evaluation study, this would
help determine the size of the error bars for measurements of different
antennas taken over the course of several days. Stable weather would
likely be a desirable characteristic of the measurement environment (no
drastic changes in ground characteristics during the measurement period).
I had to use Google to get the bagpipe joke :-)
73, Mike W4EF............
On 10/31/2020 3:55 AM, Mark - N5OT wrote:
Great idea. Do the exercise as well as you can multiple times, throw
out the outliers and average the rest.
Drones are changing the world. Bagpipe players take note.
73 - Mark N5OT
On 10/31/2020 12:17 AM, David Gilbert wrote:
I would think that testing antennas today should be easier than it
was when the K7LXC/N0AX report was done, and I don't see why an
antenna range is even needed anymore. A wideband noise source
mounted on a drone with an appropriately polarized short antenna
could fly around the antenna while a receiver on the ground connected
to the antenna took measurements. Drones are very stable these days
even in stiff winds, and while I don't think GPS positioning would
necessarily be accurate enough to define near field location, various
ways of doing so from the ground (optical triangulation, tethers,
etc) should be sufficient. Far field measurements out several
wavelengths could most likely just rely on the GPS coordinates.
All of that assumes reciprocity, of course, but even if that was in
question I'd bet that it would be relatively simple and inexpensive
to design/build a small receiver for the drone that forwarded signal
strength data to the ground via an RF or optical link.
One big advantage of using the drone, of course, would be that the
measurements could also be taken at the actual operating site,
thereby including the effects of nearby structures.
I haven't seen any reports of anyone doing this yet, but I assume
that people already have.
73,
Dave AB7E
On 10/30/2020 8:35 PM, chetmoore@cox.net wrote:
Not a FLAME. But You would likely benefit from reading the k7lxc
N0ax tribander report. After raeading it I ordered the C31XR.
Force 12 is no more but some of their antennas are mechanically
improved and sold by JK and there are A lot newer tribanders I
would like to see them test on their antenna range. Hint, tests
of some of the mosely and hy gain antennas did not fare all that
well. I had a TH6, a TH3 , TH7 and a classic ta33 all of which worked
Pretty well..........in their day. My th-3 is still a good FIELD
DAY antenna and great as a mult antenna to grab south American
mults so I don’t have to rotate the c31.
N4fx
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