In article ,
"Meindert Sprang" wrote:

"Me" wrote in message
...
this is where the Practical and empirical evidence shows that
the math isn't showing what really is hapopeneing.

I have two 1 watt Vhf handhelds, with rubber antennas.
I can talk 16 miles over water with these two radios.
Both myself and my wife are less than 6.5 ft tall.
We are both standing at sealevel. (water lapping at our feet)
Now how does you MATH explain this empirical DATA?

VHF waves tend to follow the curvature of the earth slightly (just like
light diffracts around sharp corners), which indeed gives you more range
than the maths tells you.

Meindert



Yes, Meindert (the engineer) come up with the answer. Vhf does indeed
extend beyond Line of Sight, in all cases, and your math does not take
this into account. The straight that I live on, is 16 Statute Miles
wide, and my wife stands on one side, at the end of a road, at a boat
ramp, and I stand on the other side, in front of my cabin, on the beach.
Both our feet, are being lapped at by the water, at exactly Sea Level,
at that moment, and YES, we do communicate with one watt, Motorola
handheld radios with rubber antennas, and have for the last 15 years.

You made a BAD Assumption, when you stated that VHF (156Mhz) RF
Propigation was only Line of Sight. This is the downfall of your whole
construction. When you have as many years as I have in RF
Communications, you should, by then, have a better understanding of the
basic Laws of Physics, that underpin the technology that your espousing.

Me who knows the difference between Theory and Practice....

On Tue, 11 Jan 2005 20:12:43 GMT, Me wrote:

In article ,
"Meindert Sprang" wrote:

"Me" wrote in message
...
this is where the Practical and empirical evidence shows that
the math isn't showing what really is hapopeneing.

I have two 1 watt Vhf handhelds, with rubber antennas.
I can talk 16 miles over water with these two radios.
Both myself and my wife are less than 6.5 ft tall.
We are both standing at sealevel. (water lapping at our feet)
Now how does you MATH explain this empirical DATA?

VHF waves tend to follow the curvature of the earth slightly (just like
light diffracts around sharp corners), which indeed gives you more range
than the maths tells you.

Meindert



Yes, Meindert (the engineer) come up with the answer. Vhf does indeed
extend beyond Line of Sight, in all cases, and your math does not take
this into account. The straight that I live on, is 16 Statute Miles
wide, and my wife stands on one side, at the end of a road, at a boat
ramp, and I stand on the other side, in front of my cabin, on the beach.
Both our feet, are being lapped at by the water, at exactly Sea Level,
at that moment, and YES, we do communicate with one watt, Motorola
handheld radios with rubber antennas, and have for the last 15 years.

You made a BAD Assumption, when you stated that VHF (156Mhz) RF
Propigation was only Line of Sight. This is the downfall of your whole
construction. When you have as many years as I have in RF
Communications, you should, by then, have a better understanding of the
basic Laws of Physics, that underpin the technology that your espousing.

Me who knows the difference between Theory and Practice....


The old saying by the Motorola salesman selling low band radios to the
farmers was "100 watts goes 100 miles".
It would do that on many days but you dare not design a system around
those figures.

Regards
Gary

Salesman's name was P.T. Barnum as I recall :)

"Gary Schafer" wrote in message
...
On Tue, 11 Jan 2005 20:12:43 GMT, Me wrote:

In article ,
"Meindert Sprang" wrote:

"Me" wrote in message
...
this is where the Practical and empirical evidence shows that
the math isn't showing what really is hapopeneing.

I have two 1 watt Vhf handhelds, with rubber antennas.
I can talk 16 miles over water with these two radios.
Both myself and my wife are less than 6.5 ft tall.
We are both standing at sealevel. (water lapping at our feet)
Now how does you MATH explain this empirical DATA?

VHF waves tend to follow the curvature of the earth slightly (just like
light diffracts around sharp corners), which indeed gives you more range
than the maths tells you.

Meindert



Yes, Meindert (the engineer) come up with the answer. Vhf does indeed
extend beyond Line of Sight, in all cases, and your math does not take
this into account. The straight that I live on, is 16 Statute Miles
wide, and my wife stands on one side, at the end of a road, at a boat
ramp, and I stand on the other side, in front of my cabin, on the beach.
Both our feet, are being lapped at by the water, at exactly Sea Level,
at that moment, and YES, we do communicate with one watt, Motorola
handheld radios with rubber antennas, and have for the last 15 years.

You made a BAD Assumption, when you stated that VHF (156Mhz) RF
Propigation was only Line of Sight. This is the downfall of your whole
construction. When you have as many years as I have in RF
Communications, you should, by then, have a better understanding of the
basic Laws of Physics, that underpin the technology that your espousing.

Me who knows the difference between Theory and Practice....


The old saying by the Motorola salesman selling low band radios to the
farmers was "100 watts goes 100 miles".
It would do that on many days but you dare not design a system around
those figures.

Regards
Gary

On Tue, 11 Jan 2005 20:12:43 GMT, Me wrote:

In article ,
"Meindert Sprang" wrote:

"Me" wrote in message
...
this is where the Practical and empirical evidence shows that
the math isn't showing what really is hapopeneing.

I have two 1 watt Vhf handhelds, with rubber antennas.
I can talk 16 miles over water with these two radios.
Both myself and my wife are less than 6.5 ft tall.
We are both standing at sealevel. (water lapping at our feet)
Now how does you MATH explain this empirical DATA?

VHF waves tend to follow the curvature of the earth slightly (just like
light diffracts around sharp corners), which indeed gives you more range
than the maths tells you.

Meindert



Yes, Meindert (the engineer) come up with the answer. Vhf does indeed
extend beyond Line of Sight, in all cases, and your math does not take
this into account. The straight that I live on, is 16 Statute Miles
wide, and my wife stands on one side, at the end of a road, at a boat
ramp, and I stand on the other side, in front of my cabin, on the beach.
Both our feet, are being lapped at by the water, at exactly Sea Level,
at that moment, and YES, we do communicate with one watt, Motorola
handheld radios with rubber antennas, and have for the last 15 years.

You made a BAD Assumption, when you stated that VHF (156Mhz) RF
Propigation was only Line of Sight. This is the downfall of your whole
construction. When you have as many years as I have in RF
Communications, you should, by then, have a better understanding of the
basic Laws of Physics, that underpin the technology that your espousing.

Me who knows the difference between Theory and Practice....


By the way, the difference between radio line of sight and optical
line of sight at 5 miles is only about .7 miles at that distance.

The factor to multiply the height of the antenna by is about 1.33 for
radio over optical. The difference is not great.

There are phenomenon's such as ducting that take place on a regular
basis over some radio paths. Usually not over 24 hours though.

I can assure you that I can show you many places where hand held to
hand held will not produce anywhere near 16 miles of range even over
water but on rare occasions.

Regards
Gary

In article ,
James Hebert wrote:

Readers may find this article of interest:


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 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