Line of sight communication
« on: June 09, 2016, 02:38:12 AM »
So, if the Earth were flat, why is line of sight based communication across the surface of the Earth limited to such short distances? Why are the limits of such forms of communication in agreement with the geometry of a sphere?

We know the service distance of a radio transmitter increases more or less in proportion to the square root of it's height off the ground, so we know it's not merely a matter of signal attenuation through atmosphere or environment.

If the Earth were flat, a modestly powered transmission at even a modest height should be receivable much further than it is, especially in very flat geographic regions. It just so happens though that we are able to very accurately calculate transmittable distances and it is in agreement with the geometry of a curved surface.


Re: Line of sight communication
« Reply #1 on: June 09, 2016, 02:39:54 AM »
true. There is too much evidence showing the world is round for there to be any other conclusion made.

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Offline Tom Bishop

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Re: Line of sight communication
« Reply #2 on: June 09, 2016, 02:47:41 AM »
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.
« Last Edit: June 09, 2016, 02:51:45 AM by Tom Bishop »
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

Offline Unsure101

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Re: Line of sight communication
« Reply #3 on: June 09, 2016, 02:50:13 AM »
When designing mobile (cellular) phone towers, we must to the curvature of the Earth into account in order for it to work.
If the curvature was ignored in the calculations, wireless data transmission from your phone would be near impossible.

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Re: Line of sight communication
« Reply #4 on: June 09, 2016, 02:51:12 AM »
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.
Are you sure about that? These types of radios do not use photons as their carrier!

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Offline Tom Bishop

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Re: Line of sight communication
« Reply #5 on: June 09, 2016, 02:56:08 AM »
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.
Are you sure about that? These types of radios do not use photons as their carrier!

All electro-magnetic radiation consists of photons.

Round Earth Scientists have to make up mysterious atmospheric ducting and atmospheric reflection phenomena in attempt to explain the phenomenon of traveling further than the horizon should allow, no matter how absurd. Consider Over The Horizon Radar. The photon is transmitted from the receiver, bounces off of the atmosphere in the distance, hits an object further beyond the horizon, and then bounces back off the atmosphere and again hits the receiver to register an object in the distance. Ridiculous.

They even claim that the photons can bounce between the atmosphere and the ground several times, and then back again to the receiver, with no significant scattering!

« Last Edit: June 09, 2016, 03:25:57 AM by Tom Bishop »
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

Re: Line of sight communication
« Reply #6 on: June 09, 2016, 03:11:44 AM »
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.

These are not operating on line of sight. I would suggest you read about ground waves and how signals of various wavelength propagate.

I would also pose the question why anyone would bother using a technology that takes advantage of something unnecessary such as ultra low frequency waves. A radar on the modestly high mountain above sea level would cover all required ranges.

Re: Line of sight communication
« Reply #7 on: June 09, 2016, 03:26:24 AM »
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.
Are you sure about that? These types of radios do not use photons as their carrier!

All electro-magnetic radiation consists of photons.

Round Earth Scientists have to make up mysterious atmospheric ducting and atmospheric reflection phenomena in attempt to explain the phenomenon of traveling further than the horizon should allow, no matter how absurd. Consider Over The Horizon Radar. The photon is transmitted from the receiver, bounces off of the atmosphere in the distance, hits an object further beyond the horizon, and then bounces back off the atmosphere and again hits the receiver to register an object in the distance. Ridiculous.

They even claim that the photons can bounce between the atmosphere and the ground several times, and then back again to the receiver, with no significant scattering!



The simplest explanation is that the photons just went in a straight line.

Why bother debating the merits of such advanced physics when you can use literal line of sight communication -- a laser pointer -- to test your theory?

A cheap 1mW laser pointer has been shown to have no problem traveling 20km through atmosphere. Buying a slightly higher powered one will go even further.

http://kotaku.com/one-mans-quest-to-prove-how-far-laser-pointers-reach-1464275649

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Offline Tom Bishop

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Re: Line of sight communication
« Reply #8 on: June 09, 2016, 03:28:32 AM »
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.

These are not operating on line of sight. I would suggest you read about ground waves and how signals of various wavelength propagate.

I would also pose the question why anyone would bother using a technology that takes advantage of something unnecessary such as ultra low frequency waves. A radar on the modestly high mountain above sea level would cover all required ranges.

Ground waves? Ducting?

The simplest explanation is that the photons just went in a straight line.

Quote
Why bother debating the merits of such advanced physics when you can use literal line of sight communication -- a laser pointer -- to test your theory?

The atmosphere is not perfectly transparent to all forms of EM, which is why distant mountains may be faded in the distance by atmosphere.
« Last Edit: June 09, 2016, 03:30:35 AM by Tom Bishop »
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

Offline Unsure101

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Re: Line of sight communication
« Reply #9 on: June 09, 2016, 03:28:48 AM »
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.
Are you sure about that? These types of radios do not use photons as their carrier!

All electro-magnetic radiation consists of photons.
Yes, kind of, but the carrier is not the photon. From a classical physics perspective, the radio waves are EM fields propagating through space. Once you get into quantum mechanics, it gets a bit murkier. To create a radio transmitter, the antenna needs to effectively vibrate thereby creating fluctuations in the EM field. This is what the carrier wave of an AM radio.
Like I said, this is the quantum mechanics description of EM radiation, but I didn't think that Flat Earth believers accepted any scientific discoveries since the dark ages.

Round Earth Scientists have to make up mysterious atmospheric ducting and atmospheric reflection phenomena in attempt to explain the phenomenon of traveling further than the horizon should allow, no matter how absurd. Consider Over The Horizon Radar. The photon is transmitted from the receiver, bounces off of the atmosphere in the distance, hits an object further beyond the horizon, and then bounces back off the atmosphere and again hits the receiver to register an object in the distance. Ridiculous.
Where is the evidence that this is made up? The whole reason that these radars, like the JORN, exist is because the surface of the earth is curved.

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Offline Tom Bishop

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Re: Line of sight communication
« Reply #10 on: June 09, 2016, 03:33:16 AM »
Yes, kind of, but the carrier is not the photon. From a classical physics perspective, the radio waves are EM fields propagating through space. Once you get into quantum mechanics, it gets a bit murkier. To create a radio transmitter, the antenna needs to effectively vibrate thereby creating fluctuations in the EM field. This is what the carrier wave of an AM radio.
Like I said, this is the quantum mechanics description of EM radiation, but I didn't think that Flat Earth believers accepted any scientific discoveries since the dark ages.

Incorrect. All Electro-Magnetic radiation is photons.

Quote
Round Earth Scientists have to make up mysterious atmospheric ducting and atmospheric reflection phenomena in attempt to explain the phenomenon of traveling further than the horizon should allow, no matter how absurd. Consider Over The Horizon Radar. The photon is transmitted from the receiver, bounces off of the atmosphere in the distance, hits an object further beyond the horizon, and then bounces back off the atmosphere and again hits the receiver to register an object in the distance. Ridiculous.
Where is the evidence that this is made up? The whole reason that these radars, like the JORN, exist is because the surface of the earth is curved.

It shouldn't be possible to "see" over the horizon if the earth is a globe. In order to explain what these radars do, new scientific theories had to be invented.
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

geckothegeek

Re: Line of sight communication
« Reply #11 on: June 09, 2016, 03:33:34 AM »
true. There is too much evidence showing the world is round for there to be any other conclusion made.

There is too much evidence that the earth is round that certain frequencies, such as those in radar, microwave repeaters, etc. operate in a line of  site method.
The distance is limited to the distance to the horizon which is determined by the height of the antenna due to the  curvature of the earth.
This is a well known fact to anyone who has ever worked in those fields.
If the earth was flat, the range of  certain frequency radars and microwave repeater stations could be  designed to have an infinite range.
"There is too much evidence showing the world is round for there to be any other conclusion made."
Examples are a World War II US Navy SG-1b surface search radar and a  microwave repeater system that was used by the US Federal Aviation Administration.
Their ranges were line of site due to the  curvature of the earth.
This is really a moot point because the earth is round -  a globe.

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Offline Tom Bishop

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Re: Line of sight communication
« Reply #12 on: June 09, 2016, 03:35:04 AM »
true. There is too much evidence showing the world is round for there to be any other conclusion made.

There is too much evidence that the earth is round that certain frequencies, such as those in radar, microwave repeaters, etc. operate in a line of  site method.
The distance is limited to the distance to the horizon which is determined by the height of the antenna due to the  curvature of the earth.
This is a well known fact to anyone who has ever worked in those fields.
If the earth was flat, the range of  certain frequency radars and microwave repeater stations could be  designed to have an infinite range.
"There is too much evidence showing the world is round for there to be any other conclusion made."
Examples are a World War II US Navy SG-1b surface search radar and a  microwave repeater system that was used by the US Federal Aviation Administration.
Their ranges were line of site due to the  curvature of the earth.
This is really a moot point because the earth is round -  a globe.

It's not possible for many forms of light to propagate infinitely. Visible light is affected by the opacity of the atmosphere. This is evidenced by very distant objects being discolored and muddied.
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

Offline Unsure101

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Re: Line of sight communication
« Reply #13 on: June 09, 2016, 03:43:35 AM »
Yes, kind of, but the carrier is not the photon. From a classical physics perspective, the radio waves are EM fields propagating through space. Once you get into quantum mechanics, it gets a bit murkier. To create a radio transmitter, the antenna needs to effectively vibrate thereby creating fluctuations in the EM field. This is what the carrier wave of an AM radio.
Like I said, this is the quantum mechanics description of EM radiation, but I didn't think that Flat Earth believers accepted any scientific discoveries since the dark ages.

Incorrect. All Electro-Magnetic radiation is photons.
I'm not debating that.

You stated in your original post that in low frequency radio waves:
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.
However, in order to understand the method of how these waves propagate, you have to understand that it is not the photon that is acting like the carrier wave. This is not the case for higher frequency waves however.

geckothegeek

Re: Line of sight communication
« Reply #14 on: June 09, 2016, 03:47:25 AM »
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.

Different frequencies operate in different ways. Even ham radio operators know this. I rather doubt that you would find any flat earthers who are engaged in any field of communications- amateur or professional. LOL.
« Last Edit: June 09, 2016, 03:57:36 AM by geckothegeek »

Re: Line of sight communication
« Reply #15 on: June 09, 2016, 04:02:02 AM »
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.

These are not operating on line of sight. I would suggest you read about ground waves and how signals of various wavelength propagate.

I would also pose the question why anyone would bother using a technology that takes advantage of something unnecessary such as ultra low frequency waves. A radar on the modestly high mountain above sea level would cover all required ranges.

Ground waves? Ducting?

The simplest explanation is that the photons just went in a straight line.

Quote
Why bother debating the merits of such advanced physics when you can use literal line of sight communication -- a laser pointer -- to test your theory?

The atmosphere is not perfectly transparent to all forms of EM, which is why distant mountains may be faded in the distance by atmosphere.

It doesn't have to be perfectly transparent, especially if you do it on a day with agreeable weather conditions.

There is a simple method to prove that atmosphere attenuation is not the limiting factor in visibility. Simply adjust the angle upward and point it at a tall landmass or building. This will increase the amount of atmosphere it is traveling through, proving that the laser is not being attenuated by atmosphere. The atmosphere is not massively different at a mere 100ft height difference, nor a few miles away. I'd suggest a nice large, flat, place like the salt flats in Bolivia for testing. It's the flattest place on Earth.

What you'll find is that someone sitting on the mountain top 10 miles away will be able to see your laser, but someone standing on the ground 5 miles away will not.

It's quite simple geometry and requires no real scientific knowledge. It's basic line of sight communication.


If it can travel 20km
« Last Edit: June 09, 2016, 04:04:49 AM by noonenoone »

Re: Line of sight communication
« Reply #16 on: June 09, 2016, 05:29:10 AM »
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.
That's great Tom. "Ham radio" - What? VHF? UHF? Again, you're talking out your a** acting like an expert in an area you have no expertise in.

I'm a licensed operator (B license). I don't know what's included in your licenses "over there" but at least here, they require you to know about electronics as well.

Anyway, that license gives me access to broadcast and receive @ 100 W. Though for all my balloon launches, I've used the UHF 70 cm band (~434.650 Mhz) @ 10 mW. It's pretty much as limited by line of sight as it gets.

I repeat, It's pretty much as limited by line of sight as it gets.
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Offline Tom Bishop

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Re: Line of sight communication
« Reply #17 on: June 09, 2016, 12:55:52 PM »
Yes, kind of, but the carrier is not the photon. From a classical physics perspective, the radio waves are EM fields propagating through space. Once you get into quantum mechanics, it gets a bit murkier. To create a radio transmitter, the antenna needs to effectively vibrate thereby creating fluctuations in the EM field. This is what the carrier wave of an AM radio.
Like I said, this is the quantum mechanics description of EM radiation, but I didn't think that Flat Earth believers accepted any scientific discoveries since the dark ages.

Incorrect. All Electro-Magnetic radiation is photons.
I'm not debating that.

You stated in your original post that in low frequency radio waves:
Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.
However, in order to understand the method of how these waves propagate, you have to understand that it is not the photon that is acting like the carrier wave. This is not the case for higher frequency waves however.

All EM is photonic. Please elaborate.

Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.

Different frequencies operate in different ways. Even ham radio operators know this. I rather doubt that you would find any flat earthers who are engaged in any field of communications- amateur or professional. LOL.

Different ways like bouncing off of the atmosphere and the ground several times, hitting an object beyond the horizon and then miraculously bouncing back between the atmosphere and ground to the radar receiver to register an image without any significant scatter in this process?

Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.

These are not operating on line of sight. I would suggest you read about ground waves and how signals of various wavelength propagate.

I would also pose the question why anyone would bother using a technology that takes advantage of something unnecessary such as ultra low frequency waves. A radar on the modestly high mountain above sea level would cover all required ranges.

Ground waves? Ducting?

The simplest explanation is that the photons just went in a straight line.

Quote
Why bother debating the merits of such advanced physics when you can use literal line of sight communication -- a laser pointer -- to test your theory?

The atmosphere is not perfectly transparent to all forms of EM, which is why distant mountains may be faded in the distance by atmosphere.

It doesn't have to be perfectly transparent, especially if you do it on a day with agreeable weather conditions.

There is a simple method to prove that atmosphere attenuation is not the limiting factor in visibility. Simply adjust the angle upward and point it at a tall landmass or building. This will increase the amount of atmosphere it is traveling through, proving that the laser is not being attenuated by atmosphere. The atmosphere is not massively different at a mere 100ft height difference, nor a few miles away. I'd suggest a nice large, flat, place like the salt flats in Bolivia for testing. It's the flattest place on Earth.

What you'll find is that someone sitting on the mountain top 10 miles away will be able to see your laser, but someone standing on the ground 5 miles away will not.

It's quite simple geometry and requires no real scientific knowledge. It's basic line of sight communication.


If it can travel 20km

Nice thought experiment. Feel free to put your imaginations to the test.

Actually, the existence of AM Radio, HAM Radio, and Over the Horizon Radar, where photons travel much further than the curvature of the earth should allow, suggests that the earth is not a globe.
That's great Tom. "Ham radio" - What? VHF? UHF? Again, you're talking out your a** acting like an expert in an area you have no expertise in.

I'm a licensed operator (B license). I don't know what's included in your licenses "over there" but at least here, they require you to know about electronics as well.

Anyway, that license gives me access to broadcast and receive @ 100 W. Though for all my balloon launches, I've used the UHF 70 cm band (~434.650 Mhz) @ 10 mW. It's pretty much as limited by line of sight as it gets.

I repeat, It's pretty much as limited by line of sight as it gets.


Incorrect. It is possible for HAM receivers to hear stations from hundreds or thousands of miles away on the AM band.
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

Re: Line of sight communication
« Reply #18 on: June 09, 2016, 01:20:48 PM »
That's great Tom. "Ham radio" - What? VHF? UHF? Again, you're talking out your a** acting like an expert in an area you have no expertise in.

I'm a licensed operator (B license). I don't know what's included in your licenses "over there" but at least here, they require you to know about electronics as well.

Anyway, that license gives me access to broadcast and receive @ 100 W. Though for all my balloon launches, I've used the UHF 70 cm band (~434.650 Mhz) @ 10 mW. It's pretty much as limited by line of sight as it gets.

I repeat, It's pretty much as limited by line of sight as it gets.


Incorrect. It is possible for HAM receivers to hear stations from hundreds or thousands of miles away on the AM band.

Incorrect? You were trying to enhance the likelihood of the Earth being flat by providing an example (read: generalizing) about amateur radio bands. It only takes one example to dismiss your claim, and that is what I gave you.

NB-UHF (70cm) is as line of sight as it gets. You rate the distance between a transmitter and a receiver to be about 500m because it takes nothing to disrupt the signal. However, if you send the transmitter upwards, there's no problem receiving over a distance of +40km. Besides, you cant just generalize AM frequencies like that. Low Frequency AM (300khz - 3MHz) have a wavelength range from 100-1000 meters. It's their "bouncing" properties, diffraction and their insensitive nature to be disrupted that allows receivers to decode a signal even with antennas below the horizon.
« Last Edit: June 09, 2016, 01:25:24 PM by andruszkow »
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Re: Line of sight communication
« Reply #19 on: June 09, 2016, 04:48:36 PM »

Different ways like bouncing off of the atmosphere and the ground several times, hitting an object beyond the horizon and then miraculously bouncing back between the atmosphere and ground to the radar receiver to register an image without any significant scatter in this process?


Why not just shield the signal along the x-axis while allowing it to propagate at a positive angle and confirm detection beyond the shielding? Very simple test.

This would confirm that it is in fact possible to bounce the signal off the atmosphere. This wouldn't even have to do with flat/round Earth, but simply show that you're incorrect about what is possible.

Your unwillingness to test these things is most likely rooted in not wanting to be proven wrong.