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To Harry Hapgood, re: com radio range.
50 miles out at 5000 ft ain't all that bad, Harry. However, if you believe
it should get more, take your airplane to a reputable avionics shop and have
the tech check you comm antenna's VSWR. This measurement will tell you how
well your com radio is matched to the antenna. A lousy VSWR (ratio = 1:1 is
perfect and probably impossible to attain) is usually an artifact of the
antenna design but many other things can screw it up - such as squashed or
kinked cables, bad connection to the antenna and/or the radio and faulty
cable.
A high VSWR will mostly affect the transmitter but if it's really bad, the
receiver can be bothered too.
In my Lancair, I've noticed that my transmitter, and occasionally the
receiver, exhibit some directional sensitivity. That is, ATC sometimes will
report that they can't read me and when I make a turn either way of , say 45
degrees, they hear me 5 by 5. This only happens on some frequencies and it
happens to be in the part of the band where my VSWR is highest (it'll vary
depending on the frequency being used).
I'm using a Bob Archer antenna for comm and though it's quite good, there
are some quirks.
Dan Schaefer
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