Assume the 2mhz bandwidth that appears above. You could transmit from 0 to 2mhz. LOL or 2mhz to 4mhz or 8 to 10mhz or 40 to 42mhz.

OK 0 to 2mhz is a joke and has all kinds of problems, including killing the entire AM radio band.

If you are transmitting digital video, gray scale requires bandwidth. Analog video, the grayscale comes for free.
Think about TV stations. They have a 1000 foot tower and transmit, more or less, mega watts to get 50 to 100 miles. The higher frequencies are "line of sight". You need heigh on both ends to get distance.

Are you transmitting to one receiver or many receivers? Directional antennas on both ends really help.

 

Assume the 2mhz bandwidth that appears above. You could transmit from 0 to 2mhz. LOL or 2mhz to 4mhz or 8 to 10mhz or 40 to 42mhz.

OK 0 to 2mhz is a joke and has all kinds of problems, including killing the entire AM radio band.

If you are transmitting digital video, gray scale requires bandwidth. Analog video, the grayscale comes for free.
Think about TV stations. They have a 1000 foot tower and transmit, more or less, mega watts to get 50 to 100 miles. The higher frequencies are "line of sight". You need heigh on both ends to get distance.

Are you transmitting to one receiver or many receivers? Directional antennas on both ends really help.

I am transmitting to 1 receiver and using an omnidirectional antenna.

 

If your transmitter and receiver were located on the top of mountains and are in line of sight of each other then you have a fighting chance that it will work.

 

I am transmitting to 1 receiver and using an omnidirectional antenna.

That would be a silly thing to do, unless the location of the receiver is unknown.

 

If your transmitter and receiver were located on the top of mountains and are in line of sight of each other then you have a fighting chance that it will work.

Of course the trouble is the strange constraint of “lowest frequency“ because low frequencies either want to propagate by ground wave or some form of skip. The skip zone could include the target, depending on conditions. I think the distance constraint isn‘t very instructive at all.

 

That would be a silly thing to do, unless the location of the receiver is unknown.

Why is it a silly thing to do? I mentioned the receiver is 100 miles from the transmitter and an omnidirectional antenna broadcast radio waves in all directions.

 

Because you could reduce power required hugely by using a directional antenna on each side.

 

Assume the 2mhz bandwidth that appears above. You could transmit from 0 to 2mhz. LOL or 2mhz to 4mhz or 8 to 10mhz or 40 to 42mhz.

OK 0 to 2mhz is a joke and has all kinds of problems, including killing the entire AM radio band.

If you are transmitting digital video, gray scale requires bandwidth. Analog video, the grayscale comes for free.
Think about TV stations. They have a 1000 foot tower and transmit, more or less, mega watts to get 50 to 100 miles. The higher frequencies are "line of sight". You need heigh on both ends to get distance.

Are you transmitting to one receiver or many receivers? Directional antennas on both ends really help.

Why is 0 to 2 mhz a joke? What are the problems that 0 to 2 mhz has?

 

Because you could reduce power required hugely by using a directional antenna on each side.

Unless he wants a 100-mile radius of coverage but, for simplicity of a thought experiment, he only wants to worry about the reception of one receiver on the perimeter of his broadcast area.

 

omnidirectional antenna broadcast radio waves in all directions.

Take a torch/flashlight bulb and hold it in your hand and it makes so little light it is unusable. Put the light inside a good reflector and add a lens and it makes one small spot very bright. Radio waves are the same thing. Don't send power all over the world. Send power just in one direction. When I did broadcast one of my antennas had a gain of 12. It really helps the power bill.

 

Why is 0 to 2 mhz a joke? What are the problems that 0 to 2 mhz has?

Think about what the waveform of 0Hz looks like. What would be the problem of broadcasting at 60Hz? Look up antenna size for ultra-low frequency broadcasts. Kind of interesting but

 

Your antennas have to be 5000’ tall.

 

Think about what the waveform of 0Hz looks like. What would be the problem of broadcasting at 60Hz? Look up antenna size for ultra-low frequency broadcasts. Kind of interesting but

So 0 to 2 mhz is a joke and has all kinds of problems because the antenna would be too big?

 

Why is 0 to 2 mhz a joke? What are the problems that 0 to 2 mhz has?

First, 0 is nothing.
Second, some people argue you can't transmit at very low frequencies. I disagree and don't want to argue about it.
Third, there are 1000s of transmitters in your area using frequencies less than 2mhz that will all stop working with a mega-watt transmitter in your backyard.
Forth, high bandwidth signals get pushed up to high frequencies for a reason. There are cameras that transmit 100 feet at 2.4ghz where 2mhz wide is not a problem and only eat up a small portion of the band.

 

Analog video bandwidth is 6MHz.
40MHz RF carrier looks like a good candidate.
If you transmit SSB you can go to half that.

 

Analog video bandwidth is 6MHz.
40MHz RF carrier looks like a good candidate.

So you are saying a radio signal that has 40 mhz carrier and 6 mhz bandwidth is a good candidate that meets all the criteria i specified?

 

So you are saying a radio signal that has 40 mhz carrier and 6 mhz bandwidth is a good candidate that meets all the criteria i specified?

40MHz has been used for TV broadcast.
(Note: 40mHz is a totally different frequency!)

Edit:
40MHz has a period of 25ns.
40mHz as a period of 25s, nine orders of magnitude different.

 

40MHz has been used for TV broadcast.
(Note: 40mHz is a totally different frequency!)

Can 40 Mhz radio waves travel beyond the horizon?

 

Can 40 Mhz radio waves travel beyond the horizon?

does it have to? You never made a limit on antenna size (height). Are you going to add a new constraint? If so, let us know which other constraints you haven't told us.

 

This is the last constraint. Neither transmittter nor receiver are on top of a mountain. Both transmitter and receiver are lying on the ground.