I just installed a Butternut HF9V on the galvanized steel roof of my
garage, using the roof in place of radials. Just a couple of things I
thought people might find worth knowing:
-- I could not use my MFJ 259B at the base of the antenna (standing on the
roof). Readings were wildly dependent on where I was holding the meter,
whether my hand was on the case or not, etc. Evidently standing on part of
the antenna is not recommended.
-- Resonances on the higher bands are quite far off nominal, presumably
reflecting the difference between the roof and a normal radial
arrangement. 15M is 'way high, while 10 is 'way low. 20m still centers
around 13.9 MHz, but SWR in the band is acceptable. I WAS able to adjust
80 and 40, but what with needing to get down off the roof every time I want
to measure anything, I haven't sorted out the other bands yet.
By the way, performance is quite adequate. Ran a few comparisons to Europe
on 20m last night, and it's down 6-12 dB compared with my stacked
tribanders, although QSB was also quite a bit worse on the vertical. It
also is only down a few dB with domestic stations on 40m, compared to my
yagi at 104 feet. Presumably both antennas are too low-angle for this
application.
73, Pete N4ZR
Sometimes a tower is just a tower
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