Thanks to all who replied. Aram, I haven’t forgotten *all* my high school
trig. Besides, my friends say I often go off on a tangent. So... I used this
method:
< https://gabrielhemery.com/how-to-calculate-tree-height-using-a-smartphone/>
I made several angular measurements. I tossed out the most extreme and
averaged the rest. There was some uncertainty about how far back from my roof
peak the neighbor’s roof is. The result is that the neighbor’s roof is
somewhere between 1.5 feet higher and 0.5 feet lower than my tower mast.
While the precise figure is within my error of measurement, I do know now that
three more feet of mast will get an antenna higher than the roof. I can do that
with a 5 foot piece of PVC pipe hose-clamped to the existing mast. I can
jerry-rig that for a “proof of concept.” If that works well, then I can invest
in something more permanent.
Brian on the LUG and Moose on the Oly list have tempted me greatly with visions
of laser-based measuring devices. Thanks, guys! If I get one, it can be my
very own Jewish Space Laser. With a little help from the Germans or the
Chinese!
https://www.amazon.com/gp/product/B07CN1TSGY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
https://www.boschtools.com/us/en/boschtools-ocs/laser-measures-glm165-40-187965-p/
--Peter, dictating to my iPad
(If it misconstrues, please excuse)
> On Mar 9, 2021, at 7:00 PM, Peter Klein <boulanger.croissant@xxxxxxxxx> wrote:
>
> This is sort of off-topic, but does involve photography. Is the top of my
> roof tower a bit higher than my neighbor's roof, as it appears to be? Or does
> my iPhone 7 camera's distortion or where I stood make the picture
> meaningless? This is significant because I'm thinking of putting up a
> directional antenna for VHF (ham radio), and having a unobstructed view of
> the horizon is very desirable.
> <http://gallery.leica-users.org/v/pklein/temp/IMG_1036RoofAntennas-w.jpg.html>
>
> If you know of a reasonably easy way to determine this without expensive
> surveyor's tools, please tell. ("Brother, can you spare a Theodolite?")
>
> Background: When the roof tower was installed, the house on the left was a
> one-story rambler. Now it's a McMansion.
>
> --Peter
>
>
--
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