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Bruce Woodburn
 
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Default More on radar blips and arcs... ?Bermuda Triangle?

I saw an interesting artifact while in the North Atlantic. With the range
set to 30 miles, we had a huge reflection at 25 miles... would have been
several miles long.
We were several hundred miles offshore, perfect visibility and there was
definately nothing there.

The puzzle was solved when we realised the artifact was on the same bearing
as Bermuda, 350 miles away. The antennae was catching Bermuda's reflection
of the previous pulse (which was interpreted as reflection of the current
pulse from an object 25 miles away). The difference in distance (times 2)
divided by the speed of light equaled the pulse frequency of the radar unit.
Isn't physics great when it works?

The artifact lasted about 20 minutes. We were in the area for another month
but never saw the effect again. I assume it had something to do with
atmospherics skipping the signal.

Anyone ever seen this?

Bruce


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Wwj2110
 
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Default More on radar blips and arcs... ?Bermuda Triangle?

At certain times, looking across lake ontario(appx. 50 miles wide) ,the other
side is visible. The arc over 50 miles is appx.400 '. I believe this is due to
light being reflected off the atmosphere. Im not sure if this is relative to
radar but it sounds like theres some similarities.
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Wwj2110
 
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Default More on radar blips and arcs... ?Bermuda Triangle?

At certain times, looking across lake ontario(appx. 50 miles wide) ,the other
side is visible. The arc over 50 miles is appx.400 '. I believe this is due to
light being reflected off the atmosphere. Im not sure if this is relative to
radar but it sounds like theres some similarities.
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Bruce in Alaska
 
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Default More on radar blips and arcs... ?Bermuda Triangle?

In article ,
"Bruce Woodburn" wrote:

I saw an interesting artifact while in the North Atlantic. With the range
set to 30 miles, we had a huge reflection at 25 miles... would have been
several miles long.
We were several hundred miles offshore, perfect visibility and there was
definately nothing there.

The puzzle was solved when we realised the artifact was on the same bearing
as Bermuda, 350 miles away. The antennae was catching Bermuda's reflection
of the previous pulse (which was interpreted as reflection of the current
pulse from an object 25 miles away). The difference in distance (times 2)
divided by the speed of light equaled the pulse frequency of the radar unit.
Isn't physics great when it works?

The artifact lasted about 20 minutes. We were in the area for another month
but never saw the effect again. I assume it had something to do with
atmospherics skipping the signal.

Anyone ever seen this?

Bruce



We see that type of reflection here in alaska all the time.
One of our usual weather conditions in the summer is "temp
inversion" where we get considerable RF reflection at the inversion
boundry. I have watched a similar Radar Target appear and
hold steady for hours at a time on an Xband Radar in Bristol
Bay, Alaska. It is a Radio tower 90 miles from the Radar Site
and well below the horizon. This same phenomena is used widely
in the area to communicate on VHF Radio Links out to 200 miles.
One of the "Old Radiomen" (Bill Forgey) pioneered (in the Late 60's)
4 or 5 of these "Shots" for the Canneries to communicate between
themselves on VHF. Most of these links are still in use today.

Bruce in alaska
--
add a 2 before @
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Bruce in Alaska
 
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Default More on radar blips and arcs... ?Bermuda Triangle?

In article ,
"Bruce Woodburn" wrote:

I saw an interesting artifact while in the North Atlantic. With the range
set to 30 miles, we had a huge reflection at 25 miles... would have been
several miles long.
We were several hundred miles offshore, perfect visibility and there was
definately nothing there.

The puzzle was solved when we realised the artifact was on the same bearing
as Bermuda, 350 miles away. The antennae was catching Bermuda's reflection
of the previous pulse (which was interpreted as reflection of the current
pulse from an object 25 miles away). The difference in distance (times 2)
divided by the speed of light equaled the pulse frequency of the radar unit.
Isn't physics great when it works?

The artifact lasted about 20 minutes. We were in the area for another month
but never saw the effect again. I assume it had something to do with
atmospherics skipping the signal.

Anyone ever seen this?

Bruce



We see that type of reflection here in alaska all the time.
One of our usual weather conditions in the summer is "temp
inversion" where we get considerable RF reflection at the inversion
boundry. I have watched a similar Radar Target appear and
hold steady for hours at a time on an Xband Radar in Bristol
Bay, Alaska. It is a Radio tower 90 miles from the Radar Site
and well below the horizon. This same phenomena is used widely
in the area to communicate on VHF Radio Links out to 200 miles.
One of the "Old Radiomen" (Bill Forgey) pioneered (in the Late 60's)
4 or 5 of these "Shots" for the Canneries to communicate between
themselves on VHF. Most of these links are still in use today.

Bruce in alaska
--
add a 2 before @


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Art
 
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Default More on radar blips and arcs... ?Bermuda Triangle?

Take a look at this website. They predict tropospheric ducting based
on temperature, humidity and pressure. The URL is:
http://www.iprimus.ca/~hepburnw/tropo.html
Art


"Bruce Woodburn" wrote in message ...
I saw an interesting artifact while in the North Atlantic. With the range
set to 30 miles, we had a huge reflection at 25 miles... would have been
several miles long.
We were several hundred miles offshore, perfect visibility and there was
definately nothing there.

The puzzle was solved when we realised the artifact was on the same bearing
as Bermuda, 350 miles away. The antennae was catching Bermuda's reflection
of the previous pulse (which was interpreted as reflection of the current
pulse from an object 25 miles away). The difference in distance (times 2)
divided by the speed of light equaled the pulse frequency of the radar unit.
Isn't physics great when it works?

The artifact lasted about 20 minutes. We were in the area for another month
but never saw the effect again. I assume it had something to do with
atmospherics skipping the signal.

Anyone ever seen this?

Bruce

  #7   Report Post  
Art
 
Posts: n/a
Default More on radar blips and arcs... ?Bermuda Triangle?

Take a look at this website. They predict tropospheric ducting based
on temperature, humidity and pressure. The URL is:
http://www.iprimus.ca/~hepburnw/tropo.html
Art


"Bruce Woodburn" wrote in message ...
I saw an interesting artifact while in the North Atlantic. With the range
set to 30 miles, we had a huge reflection at 25 miles... would have been
several miles long.
We were several hundred miles offshore, perfect visibility and there was
definately nothing there.

The puzzle was solved when we realised the artifact was on the same bearing
as Bermuda, 350 miles away. The antennae was catching Bermuda's reflection
of the previous pulse (which was interpreted as reflection of the current
pulse from an object 25 miles away). The difference in distance (times 2)
divided by the speed of light equaled the pulse frequency of the radar unit.
Isn't physics great when it works?

The artifact lasted about 20 minutes. We were in the area for another month
but never saw the effect again. I assume it had something to do with
atmospherics skipping the signal.

Anyone ever seen this?

Bruce

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Wwj2110
 
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Default More on radar blips and arcs... ?Bermuda Triangle?

That is a mirage. It sounds as if the radar was having its own form of
mirage as well.


a mirage does not have lights in it that line up with the coordinates of
cities on the opposite side of the lake.
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