On Sun, 23 Apr 2017, highlandham wrote:

On 23/04/17 04:03, Jeff Liebermann wrote:
quote =====
When you're on the water line, antenna height does make a big
difference. Prepare a roll of coax cable setup as an RF extension
cable. Attach connectors and adapters so that they fit the radio and
the antenna. If in trouble at sea, lash the antenna to the top of a
pole or oar to gain altitude. A separate antenna, such as a common
ground plane or coax sleeve antenna at the end of the coax cable would
make a better antenna than a rubber ducky.
unquote =====

A simple alternative to the J-Pole antenna would be a ground plane antenna
made of welding rod material on an SO-239 socket with a 4 hole square flange
with a vertical quarter wave radiator and 4 hinged radial elements,the
latter under 45 degrees when in use .
The SO-239 socket would be connected to a PL-259 connector and a suitable
length of coax.

But on a kayak? It won't do much good lying on the kayak, and unless you
get it high enough (which has problems in itself), you'll poke your eye
out.

Why not go for something that doesn't need horizontal radials.

Michael