Not always true Charley. Those are not ALWAYS "good heights". You
forgot one important thing for grade one....HFTA. Without HFTA those heights
are just guesses. Most hams' stations are not on a flat plane and those
numbers can be very far from a "good height".
How do I know this? When I lived in KH6 I modeled my QTH and found that
anything than 90 feet for 20, 15 and 10 would suck. In fact anything higher
than 50 feet or so would be lousy on 10. Now mine was a pretty extreme
case with a ton of rolling hills and mountains, but I've modeled dozens of
QTHs all over including FL and have found that even relatively flat locations
can affect optimal antenna height.
HFTA, HFTA, HFTA!
One other thing, rather than getting a long boomed monster it is better to
have two small 3 element antennas stacked...better performance, which
includes the ability to BIP/BOP/TOP/BOT. I wouldn't trade my two little A-3WS
on 12/17 stacked for a 6 el at the height of the top one. Not only that,
the small antennas are easier to install and maintain than a 6 el monster.
K4XS
In a message dated 4/16/2015 11:34:16 A.M. Coordinated Universal Tim,
k4vud@hotmail.com writes:
1. Put lots of aluminum and wire in the air. The more elements on your
yagi and the wider spacing the better. The good heights are 70, 120, or
140 feet. Running an IC-718 into six elements is way better than a IC-7851
into a C-3 or a 5BTV. Double your budget for the rotor.
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