Rodger,
Elevated verticals with elevated 1/4 w. radials will work better on
the HF high bands than ground mounted verticals partly because they
are elevated enough to clear obstructions that attenuate or block the
transmitted RF on the high bands. Height helps on the high bands for
receiving also. It doesn't hurt on the low bands but below 40 m. it
is harder to physically achieve the height needed to have a true
elevated vertical and elevated radial system that's isolated from
earth. Hams try what they think is an elevated vertical on 75 (10
feet off the ground let's say) but it doesn't seem to work as well as
lots of radials and vertical on the ground because their elevated
vertical isn't high enough to make a difference so they get the
impression it is worse or makes no difference and generalize that to
all frequencies. On low frequencies where wavelengths are long
enough to reduce or eliminate the effect of relatively small
obstructions that might be a problem on 29 MHz, a ground mounted
vertical will work okay. So the bottom line is it's best to go with
the costs that impose structural limitations and elevate on the high
bands where it is cheap to do so, and go with ground mounting and lots
of surface or buried radials on 75 and 160 meters where such
construction is easy (or easier) and more affordable and the longer
waves are not affected as much by ground clutter.
Re fresh water: Fresh water has poor ground conductivity by itself.
But fresh water when combined with the salts and minerals in earth
becomes a key ingredient in good ground conductivity. Bone dry dirt
is a lousy conductor. Each separately is no good. But when the two
tango, everything comes together. So, your lake isn't the thing
that's helping you out. It is the land around the lake where the
water table is probably high and the ground moist, that is letting
your verticals and ground system perform. You still need radials but
they are aided by that land and its lake water supply. Farther away
from the lake you probably have ground that drains and dries out more
often. Not as good.
73
Rob
K5UJ
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