Long range (high power?) 433MHz, 916MHz, 2.4GHz transceiver

[Sam Acme]

How much RF power required for more than 600Km line of sight (say from a
satellite to earth) data communication?

Is there any off the shelf solution (or home made) for such a system?
(Transceiver on the satellite must be small, light weight, low power-high
efficient, while we do not have such restrictions on the other transceiver
to be used on earth)

Do we need special license to use transceivers at these frequencies?

 

[Richard Crowley]

"Sam Acme" wrote ...

How much RF power required for more than 600Km line of
sight (say from a satellite to earth) data communication?

Depends on the location, size, sensitivity, etc. of the receiving antenna.
Reliability required, dozens of other factors. Some are only a few watts.
(For expensive receivers with large dishes.) Some are several dozen watts.
(For Direct Broadcast to 18-24-30 inch dishes.)

Is there any off the shelf solution (or home made)
for such a system?

Depends on what YOU mean by "off the shelf". All the satellites up there are
"off the shelf". None of the people who operate them built them themselves
(except OSCAR amateur sats.)

(Transceiver on the satellite must be small, light weight,
low power-high efficient, while we do not have such
restrictions on the other transceiver to be used on earth)

Yeah. Those are the generic parameters within which everyone works.

Do we need special license to use transceivers at these frequencies?

Generally, Yes, at those distances/powers.

 

[Paul Burke]

Sam Acme wrote:

How much RF power required for more than 600Km line of sight (say from a
satellite to earth) data communication?

Is there any off the shelf solution (or home made) for such a system?
(Transceiver on the satellite must be small, light weight, low power-high
efficient, while we do not have such restrictions on the other transceiver
to be used on earth)

Do we need special license to use transceivers at these frequencies

The tragedy of the commons. The open bands are usable because the power
is limited. Then people start cheating, and increasing the power, making
these frequencies unusable for those who stick to the rules. So they
have to increase thir power- a classic arms race. The limit (for 433 in
the UK) is 10mW.

If you can afford a satellite, you don't need to use these frequencies!

Paul Burke