Questions tagged [radio]
244 questions
14
votes
3 answers
Where does background noise go on a radio station?
If you tune a radio to a frequency where there is no station broadcasting, you hear noise. It's pretty loud, just as loud as the music that comes in when you find a station. And yet, when you do find a station and you have good reception, the…
Mason Wheeler
- 2,162
6
votes
0 answers
What are the fundamental limits of very tiny radios?
For a hard SF story, I'm wondering about the physical limits of communications devices in a micro robot, say, the size of a mosquito. Figure one microgram mass.
Real technology has already come a long way since stories on this subject such as…
JDługosz
- 5,297
3
votes
2 answers
Naive question about Analog and Digital Signals
I have just started telecommunications in high school Physics. We are currently studying analog to digital conversion. I have 2 questions :
How is a "digital" signal transmitted? As far as I know, you can turn an analog signal digital by sampling…
Sal_99
- 423
3
votes
1 answer
Why can radio telescopes use wire mesh as their parabolic dish?
Radio telescopes use wire mesh to save cost. How does that work? Won't the waves go through the gaps?
Yusuf Abukar
- 531
2
votes
1 answer
How to make radio transmitter and reciver
I want to make a simple but useful radio transmitter and reciver.I dont know which one is better, Fm or Am or other types?
Just want it to send pulses like morse code not complicated voice or other stuffs.(plus all things needed like transistors and…
Nemexia
- 199
2
votes
2 answers
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 transmitted back at higher frequency or in what terms it is…
Ryan
- 493
2
votes
1 answer
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 to determine the rough range of the radio signal?
Ryan
- 123
1
vote
1 answer
Do long delayed echo occur on Mars and on the Moon too?
Long delayed echoes (LDEs) are radio echoes which return to the sender several seconds after a radio transmission has occurred.
Do LDEs occur on other planets and moons too? Like for example on Mars, Moon, Venus, Titan etc.
Joe Jobs
- 233
1
vote
2 answers
Is there a quantifiable tradeoff (in terms of effective broadcast distance) between the height of a radio tower and the power of the transmitter?
I have a dataset on radio stations with the following variables:
the power of the transmitter, in watts
the coordinates of the radio tower
I can easily get the elevation at those coordinates and the average elevation of the surrounding area. I…
Michael A
- 135
1
vote
1 answer
When labelling the axis of an AM Signal's frequency spectrum diagram, how can I calculate the frequencies?
If I have an AM signal with the following carrier and message tones;
Carrier: Vc = 120 cos(2π 0.5 x106)t
Message: Vm = 40 cos(2π 4 x103)t
With a system resistance of 50 Ω,
I can calculate the power of each component.
Carrier Power: Ac2 / 2R
=…
x3nr0s
- 111
1
vote
1 answer
How does the Hertz Oszillator create radio waves?
In his proof of the existence of radio waves Hertz used the setup depicted in the following figure:
A sparc is created at regular intervals when the induction coil (2) creates a potential difference high enough to cause the sparc.
Wikipedia…
Beginner
- 153
1
vote
0 answers
Does mobile phone user density in an area affect signal reception?
Whenever I go to a very crowded area (like during New Year celebration), where a lot of people gather in a space, usually my phone's data connection becomes very bad and even stopped working. Even the "EDGE/3G" indicator will go missing. Is this…
rcs
- 121
1
vote
0 answers
Baby monitor has more static when toilet is flushed?
I have a baby monitor in the basement of my house, and it's picking up the signal of the microphone transmitter on the second floor. It's not a great quality monitor, so there's always a small amount of static if I turn up the volume on the…
Fuhrmanator
- 111
- 2
0
votes
1 answer
How far would a radio signal propagate in free space as compared to Earth's atmosphere?
A curiosity question.
Radio Propagation within Earth's atmosphere is via atmosphere. Broadly speaking a signal loses strength between bouncing off the ionized layer, and absorption by various earthy elements.
If an identical signal were to be…
Everyone
- 4,703
0
votes
1 answer
What is a radio echo?
Simply that: what is a radio echo? And when it was first discovered?
By searching on Google I get results like Amazon Echo and Echo (radio station)
Joe Jobs
- 233