On 9/2/2013 1:11 AM, Fred McKenzie wrote:
In ,
wrote:

I doubt I'll be mounting this in a boat although that is a possibility
someday, I do have a ski boat. But more likely is that I'll mount it at
my house on a lake to provide some amount of emergency monitoring. So I
expect to mount it in the pickup so it can be easily removed and brought
into the house. I guess that means a second antenna too.

Rick-

I am assuming you can manage the legal requirements for use of the
radio. As others mentioned, a license may be needed.

One question you must address, is what kind of range do you need to
cover? VHF radios are essentially line-of-sight. Due to the curvature
of the earth, the "radio horizon" will limit your range.

You can estimate the distance in miles to the radio horizon, as the
square root of twice the altitude of your antenna in feet. For example,
the antenna on the roof of your truck will be approximately five feet
off the ground. The square root of ten is about 3.2, so your horizon on
level ground will be about 3 miles away.

You can add the distance to the kayak's horizon to yours. So it would
matter if the kayak is on a mountainous stream or on the open ocean or
lake.

If vehicle mounting does not provide the range you need, a tall antenna
may be required at the house. (Have you considered using cell phones?)

Hi Fred, I appreciate the response.

I'm not sure there is a lot of value to calculating the line of sight
for the antenna mount. I don't have much choice in the mount other than
having to make it lower because of some practical consideration like
hitting bridges... As to need, I want the max I can get of course. The
other end of the link will all be handheld radios.

The kayaks will be on the Chesapeake Bay, but close to shore. So land
obstructions will be the limiting factor most of the time. At least it
seemed that way on prior trips. But I don't have a lot of experience
with the hand held units we used so I'm not sure what I should have
expected.

The sort of issue I'm more interested in discussing are things like what
type of antenna and how best to mount and connect it to the radio. Of
course, I'm interested in the radios if anyone here has experience with
them. I see 25 Watt (which I'm assuming is the max available) units at
the bottom end for just over $100 and others which seem to be similar in
regards to the specs I understand for over $200 and of course the prices
run upward too. Are there aspects I should look for that I need to dig
deeper into the specs to find? For example is there some spec on the
internals of the receiver that would make a weakly received signal more
clear than another radio? What about the speaker itself? Would it be
better to have an external speaker or is the internal speaker usually ok?

I'm looking for advice from those who are experienced with marine VHF.
Of course, I don't know what I don't know, so I'm looking for help
figuring out the questions.

--

Rick