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6
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2answers
171 views

References for Radio Imaging?

I'm really intrigued by a bunch of questions like 'what do radio waves look like?' 'how much RF radiation is there in the town I live in?' 'how specifically does RF imaging work?' But I think I need ...
3
votes
3answers
6k views

Penetration versus Frequency

I would like to know the relation between penetrating ability and the frequency of a wave. For example, gamma waves have high frequency and high penetrating power: intuitively I imagined this as ...
4
votes
1answer
44 views

Missing radio source coordinates in G/T measurement technique ITU-R S.733.2

Section 3 ‘Suitable radio stars’ of this recommendation lists the different stars/nebula and their corresponding flux-densities that can be used in the G/T measurement. There is no reference to the ...
1
vote
2answers
376 views

Working of a crystal radio

I have been reading about how a crystal radio works and I have one question below: It says, the energy in form electric current from a specific frequency will be stored in the coil (or a resonator) ...
0
votes
1answer
428 views

What makes up a resonator of radio?

I was reading this article about resonators. Quote: The sine wave that matches that particular frequency will get amplified by the resonator, and all of the other frequencies will be ...
2
votes
2answers
707 views

How does repeater amplify the radio signals?

When you send some kind of radio signals at some frequency say 5 GHz to a repeater and it transmits it back at higher power, what change is made to the radio signal? For example: Will it be ...
4
votes
4answers
2k views

How does radio receives signal from particular station?

When you tune your radio (digital or analog) to receive say 100 MHz frequency and while in the environment there are hundreds of channels everywhere around the radio. How does it chooses to receive ...
0
votes
1answer
1k views

reflection, refraction and diffraction occur in radio waves, which one occurs the most?

One of the things about Radio waves is that they undergo different behaviors such as reflection, refraction and diffraction when in contact with obstacles such as walls, buildings etc. what i want to ...
11
votes
3answers
588 views

Why is this radio telescope's reflector spherical and not parabolic?

This is the Arecibo Observatory in Arecibo, Puerto Rico. Its reflector is spherical, measuring 1,001 ft. in diameter. It is considered the most sensitive radio telescope on Earth, but the fact that ...
8
votes
1answer
111 views

Where can I find information for how to create amateur radio telescope?

Where can I find good source of information for how to create amateur radio telescope. Particularly interested in creating Fresnel Zone Plate Antennas (aka flat dish). design, diagrams, ...
2
votes
3answers
2k views

Is visible light and radio waves made of the same thing?

I understand that there is such a thing as the electro magnetic spectrum, and that light and RF are both on it, so dose that mean that they are made of the same thing? Just at different frequencies.
6
votes
2answers
192 views

Multiple channels of information in single electromagnetic wave?

I'm trying to understand how can multiple radio stations transmit information just by transmitting using different frequency. The way I understand it all those different frequency waves add up to a ...
4
votes
1answer
264 views

Why is it that when driving in a car, and a lightning bolt strikes, my AM radio gets cut off for a while, but FM stays on?

I noticed this one day, a lightning/thunder occurred and my Fabulosa Spanish music died for a second. But not FM?
2
votes
5answers
684 views

Radio waves within an atom

What effect does the quantum world have on radio waves? For example, if I could shrink myself down and stand on the nucleus (or even smaller sub atomic particles making up the nucleus) with a device ...
6
votes
1answer
3k views

Adverse Health Effects of Strong Radio Waves

A while ago, I was hiking near the Hollywood Sign in Los Angeles. When I got to the sign, I found out it was fenced off; with several signs and a security camera promising prompt enforcement. As I was ...
4
votes
4answers
4k views

Understanding the cause of sidebands in Amplitude Modulation

I've read it many places that Amplitude Modulation produces sidebands in the frequency domain. But as best as I can imagine it, modulating the amplitude of a fixed-frequency carrier wave just makes ...
2
votes
1answer
724 views

Determining a radio signal's range

If I know the: Frequency Effective Radiated Power Height Above Average Terrain Radiation Center Above Mean Sea Level Radiation Center Above Ground Level of a radio signal / tower, is there a way ...
1
vote
1answer
849 views

How radio waves penetrate through buildings?

For example how radio signals of a base transceiver station (BTS) penetrate through buildings?
7
votes
1answer
4k views

How does a digital radio tuner work?

I believe I understand how tuning a radio with an analog tuner works: turning the dial physically changes the length of the antenna, which determines which broadcast wavelength will resonate in the ...
7
votes
3answers
1k views

How do radio telescopes work?

If I search online for how radio telescopes work, the found articles talk about how RF is on the spectrum, etc, how the parabolic collector is the aperture which contributes to the sensitivity and ...
2
votes
1answer
213 views

Radio waves and frequency of photon

Is 89MHZ station emitting photons of 89MHZ frequency? (I mean $\nu$ in $E=h\nu$).
1
vote
1answer
226 views

Cellphone RF radiation

First, what determines the strength of an RF signal? Why is it said that a cellphones radiates more energy when the reception from signal tower is lower in strength. Why is it said that RF gets ...