"James Hebert" wrote
VHF Marine Radio Communication

http://continuouswave.com/whaler/reference/VHF.html

There seems to be some confusion regarding the
calculation for radio horizon. I am afraid I did
not collect anecdotal reports from anonymous USENET
contributors, but instead relied on other sources.

Cf.: definition of radio horizon:

http://amsglossary.allenpress.com/gl...radio-horizon1

James, don't confuse 1w-rubber-duck man (anonymous "me" contributor) with
logic. Heck, after reading his story, I may pull down my antenna and replace
it with a rubber-duck. After all, I only get 20-25 miles reliable range to
surface craft from a 60' amsl antenna w/25w! This might have something to do
with small craft's antenna rocking through an arc of 60 degrees at the
entrance to the Chesapeake Bay!

Tropospheric Ducting is a real problem with VHF-Marine. While Bruce has some
interesting stories to tell about making use of that up North, we normally
find it a real hindrance to good communications in the mid-Atlantic. Having
five or more CG Groups trying to answer the same mayday, and hearing traffic
from a hundred or more miles up and down the coast is not a good thing for
vhf-marine radio.

see http://home.cogeco.ca/~dxinfo/tropo.html for ducting forecasts

Jack Painter
Virginia Beach, Virginia

On Wed, 12 Jan 2005 01:43:12 -0500, "Jack Painter"
wrote:



Tropospheric Ducting is a real problem with VHF-Marine.

yes, as a ham i once talked from allentown, PA to n. carolina on VHF
FM in the ham bands.

While Bruce has some
interesting stories to tell about making use of that up North, we normally
find it a real hindrance to good communications in the mid-Atlantic. Having
five or more CG Groups trying to answer the same mayday,

yes, we CG radio operators try to avoid that situation but it's
sometimes inevitable. what's even worse is that we sometimes don't
respond to a mayday, assuming it's in some other CG AOR.


---------------------------
to see who "wf3h" is, go to "qrz.com"
and enter 'wf3h' in the field

My turn for a radio sea story.
I was on Barter Island...north slope of Alaska near the Canada
border (Kaktovik), when we had a three day RF 'event'. Whereas
we generally could communicate with over-the-pole aircraft at
ranges of 200 miles, we suddnely couldn't talk to them until they
were just about overhead. Our radar also suddenly started painting
the fuel tanks of the next DEW site west...but we couldn't see aircraft
50 miles away. Talk about refraction!
Just for the record, I'm an RF guy too...I worked for a few years doing
path studies, with all the measuring gear to confirm theory. The end results?
On average, the math worked...but there were days it didn't. The more
marginal the predictions (in terms of range), the more it varied from day-to-day.
The folks paricipating in this thread suggesting that the physical/optical model
of the earth is not the same as the RF model are right on. 4/3K ring a bell?
Cranky tonight Norm B


On Wed, 12 Jan 2005 22:51:00 GMT, (Bob) wrote:

On Wed, 12 Jan 2005 01:43:12 -0500, "Jack Painter"
wrote:



Tropospheric Ducting is a real problem with VHF-Marine.

yes, as a ham i once talked from allentown, PA to n. carolina on VHF
FM in the ham bands.

While Bruce has some
interesting stories to tell about making use of that up North, we normally
find it a real hindrance to good communications in the mid-Atlantic. Having
five or more CG Groups trying to answer the same mayday,

yes, we CG radio operators try to avoid that situation but it's
sometimes inevitable. what's even worse is that we sometimes don't
respond to a mayday, assuming it's in some other CG AOR.


---------------------------
to see who "wf3h" is, go to "qrz.com"
and enter 'wf3h' in the field