On Sep 25, 10:51 am, Larry wrote:
John H. wrote :

Anyone - Is the performance of the 5' antenna seriously below that of the
8'er?

None whatsoever. I got to the horizon on a Metz Manta 6 halfwave at butt
level in a Sea Rayder jetboat all the time.

VHF only goes to the horizon, line of sight. To get further, you must
extend the horizon with ALTITUDE. 5' to 8' means nothing.

Screw a bunch of sun-destroyed fiberglass rods. The Metz is guaranteed for
life unless you lose the whip out of it. All the USCGs boats use the Metz,
a testimonial to its rugged construction. Completely self-contained. No
ground plane required. It'll work the horizon holding it in your hand.http://www.metzcommunication.com/manta6.htm
Great company, too.

This guy has it on sale:http://www.northeastmarineelectronics.com/index.asp?
PageAction=VIEWPROD&ProdID=2984
$34! That's half price!

Larry
--
Search youtube for "Depleted Uranium"
The ultimate dirty bomb......

If distance goes as square root of the height, a 3' antenna mounted on
the same mount as the 8' antenna will reduce my distance by only about
40%.

I may be wrong about this but I think the shorter antennaes are less
"gain". This means they send less power in a horizontal plane.
Sailboats use low gain antennaes because they heel but generally have
them up very high.

Bottom line, I suspect the real answer is that the 3' antenna probably
loses more than 50% of the range due to "gain" and distance to
horizon.

My options (with bimini):

1. Mount the 8' antenna on the side "gunnel" where it would interfere
with casting AND be about 2' lower, effectively being the same as a 6'
antenna (except for gain) AND requiring more coax.
2. Mount the 8' antenna on the heavy stainless bimini tube support
getting back 1' of height.
3. Replace the 8' antenna with a 3' antenna but carry the 8' one for
use in an emergency.