rickman wrote:
On 4/23/2017 10:17 AM, Ralph Mowery wrote:
In article ,
says...
On Sat, 22 Apr 2017 12:43:39 -0400, rickman wrote:
I've also considered the possibility of a higher powered unit built into
the boat with a small remote control.
A higher power transmitter will help the Coast Guard hear you but will
do nothing for you hearing the Coast Guard. More antenna gain, and a
higher antenna are better solutions.
Going from 5 to 25 watts of FM will gain almost nothing. Raising the
antenna several feet from the sitting down position will gain a lot.
Are you saying that a hand held 5 watt transceiver with a rubber ducky
antenna will reach all receivers because of the line of sight
limitation? Is that true even for contacting a land station with a 200
foot high antenna? A 3 foot high antenna and a 200 foot high antenna
give nearly 20 statute miles of range. Will 5 watts be heard that far
away?
Radio amateurs have launched satellites which usually have about 1 to 5 W
of power on VHF and UHF. Those can be clearly heard on a portable
with a very small antenna even when 2000-3000km away.
The loss of signal on line of sight is easy to overcome with narrow
band modulation and this kind of power. It is the "beyond line of sight"
attennuation that is the problem. Everything you can do to remove that
will help a lot more than power.
Today I was working at the repeater in our local radio/tv tower. We
were at 220m above ground level and it was easy to work over a repeater
about 80km away from us using only a handy with 1W of output. Only
because at that height this is (almost) line of sight.