James wrote:
Any recommendations on this ? I know that an atv would not provide much
of a ground plane, so I think a 1/4 wave would be out of the question.

For optimum performance, a 5/8WL needs a better ground
plane than a 1/4WL. I once provided four radial whips
attached to the luggage rack on my motorcycle which
worked with a 1/4WL vertical. It performed well.

Any recommended "type" (wavelength, etc) and brand for this use ?

On my bicycle, I use a J-Pole made out of ladder-line.
It is attached to a fiberglass bicycle flag pole. It
doesn't need a ground plane. This should work well on
an ATV. You may even already have the fiberglass flag
as is required when riding on many beaches.
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73, Cecil http://www.w5dxp.com