On Sun, 18 Jan 2004 06:15:40 -0500, "Bruce"
wrote:

Brian and Gary...good stuff. Now understanding the loss of power, it
would make sense to get an amp (Idon't think it would be legal) or have a
second line run to the spreader on the mizzen.That would drop the run down
to 30' and a corresponding increase in power.
Thanks for you help
Bruce

The amp IS illegal under normal use. However, most don't realize that
in an emergency situation where life is endangered, all radio laws are
null and void and any power is fine if it saves lives.



Larry W4CSC

As has been pointed out, the cable loss (within reason), is a somewhat moot point.

Given an antenna height of X, it is not hard to calculate the maximum expected range, plus some for
refraction, then also given the typical receiver sensitivity, (assume 10 microvolts for a
not-so-good receiver), and antenna gain, you'll find that the power required at the antenna is not
much. When the boat's rock and roll effect on the antenna pattern is considered, the power
requirements of course must go up. As a side note: low gain antennas are better in this respect,
assuming the low gain is due to an wider vertical beam-width, and not just poor design.

But in my estimation, the real key to reliable marine VHFcommunications is in the connectors.

When a young lad I spent 5 years maintaining antennas (all frequencies) in a coastal environment,
(actually, within 200 yards of the beach) and can assure you that an unprotected/exposed connector
in salt air can bring an antenna to its knees in 3 to 6 months.

Norm

As has been pointed out, the cable loss (within reason), is a somewhat moot point.

Given an antenna height of X, it is not hard to calculate the maximum expected range, plus some for
refraction, then also given the typical receiver sensitivity, (assume 10 microvolts for a
not-so-good receiver), and antenna gain, you'll find that the power required at the antenna is not
much. When the boat's rock and roll effect on the antenna pattern is considered, the power
requirements of course must go up. As a side note: low gain antennas are better in this respect,
assuming the low gain is due to an wider vertical beam-width, and not just poor design.

But in my estimation, the real key to reliable marine VHFcommunications is in the connectors.

When a young lad I spent 5 years maintaining antennas (all frequencies) in a coastal environment,
(actually, within 200 yards of the beach) and can assure you that an unprotected/exposed connector
in salt air can bring an antenna to its knees in 3 to 6 months.

Norm