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submitted 1 month ago* (last edited 1 month ago) by [email protected] to c/[email protected]

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https://en.m.wikipedia.org/wiki/RT-64

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[–] cmhe 4 points 1 month ago* (last edited 1 month ago) (1 children)

These radio telescopes don't transmit anything at all, they listen to radio waves coming from the cosmos. Much like a normal telescope doesn't transmit light.

If you invert the flow of the electrons, a receiver becomes a transmitter.

Speakers can become bad microphones and vice versa. Pretty sure that a radio telescope is a very bad transmitter for human music, but it could be possible with some changes...

[–] stevestevesteve 7 points 1 month ago (1 children)

if you invert the flow of electrons, a receiver becomes a transmitter

Ehh not really. That's kind of like saying if you invert the flow of photons, your eyes work as flashlights.

"It could be possible with some changes" the changes would amount to removing the receiver and replacing it with a transmitter. In this specific case I'm not sure if a transmitter already exists at this antenna and it's definitely possible one does, but that's not a guarantee at all

[–] cmhe 6 points 1 month ago* (last edited 1 month ago) (2 children)

There is no such big differences between a light emitting (LED) and a light receiving diode (photodiode), they are just the reverse of each other. In fact photodiodes can even emit light, but very inefficiently. Same in reverse, LEDs can also detect light, just badly.

It seems like most efficient energy conversion methods can be used in both directions.

[–] stevestevesteve 1 points 1 month ago (1 children)

An LED (or photodiode used as one) is a fairly simplistic device compared to an assembled receiver / transmitter. Just like you can burn gasoline in a car but you can't push a car to turn the engine to make gasoline - it's a complex system that really only works one way.

[–] cmhe 0 points 1 month ago (1 children)

Nothing gets burned or otherwise destroyed when receiving EM radiation via a dish and converted it into electricity via a receiver.

Sure, the amplification stage of the process likely works only one way, and should be replaced in order to send something.

The one way process of burning oil to generate heat seems much more primitive than the energy conversion offered by a diode, TBH.

You can push or tow an electric car and charge their batteries. Because electric motors are also generators.

Even with your simplistic fossil fuel car in your example the alternator within can also be used as a motor.

[–] stevestevesteve 1 points 1 month ago

Even with your simplistic fossil fuel car in your example the alternator within can also be used as a motor.

Not by "simply reversing the flow" it can't. You'd need to remove and replace many components, just like the example of changing an Rx to Tx system

[–] [email protected] 0 points 1 month ago

Yes, but you would blow out most of the amplification circuitry in a radio telescope reciver if you tried to use it for broadcast at any kind of power.