Radio Definition and 671 Threads

Homework Statement An AM radio station broadcasts with a power of 21.0 kW at a frequency of 910 kHz. Estimate the intensity of the radio wave at a point 18.0 km from the broadcast antenna. Homework Equations I= p/A I1/I2=r2^2/r1^2 w=2pi f The Attempt at a Solution From the...

I've been puzzling how it is that you can tune into a signal on a particular frequency. How can it be possible to get rid of all the other signals that are added together? I don't know how much of this makes any sense, but I have tried to specify the problem mathematically. Suppose R_1(t)...

[SOLVED] Find an FM Radio station's wavelength, frequency given Homework Statement An FM radio station broadcasts at a frequency of 101.3 MHz. What is the wavelength?Homework Equations Vsound = 343m/s @ 20 deg C λ = v/fThe Attempt at a Solution I used the formula λ = v/f and got something...

Hello good members and guests of PhysicsForums. Whats the deal with this? Are we going to be fueling vehicles with sea water now? http://green.yahoo.com/index.php?q=node/1570

Hey guys. I know conspiracy theories and the discussion of 9/11 in general is frowned upon on this forum, but I am looking for some experts in structural engineering, aeronautics, physics etc. for my 9/11 educational radio show tomorrow morning. I use a website called BlogTalkRadio to do my show...

I am looking at a cheap $100 shortwave radio, the Kaito KA-2100 (google it, there are a bunch of links, too many to mention), and I would like to know if disabling the AGC (automatic gain control), is possible for use as a radio telescope. Now I don't know that much about radio and electronics...

If net neutrality isn't enforced, and businesses are allowed to manipulate the pipes of the internet possibly allowing only a small number of websites who can afford the fee faster transmission, do you predict that The Internet will just be another version of cable or satelitte tv , where , just...

Seems like a pretty basic question.. Most will say Marconi... But is that really correct ? Aquafire

first HI to everyone! I have a question: is there a (simple) way to reduce radio wave speed at it's source - transmitor (e.g. to 100 or 1000x less then the speed of light)? thx in advance

Homework Statement AM radio allows a speration of 10kHz between frequencies of different radio stations. Why do AM radio receivers need a large Q? Estimate the Q required for good AM reception. The Attempt at a Solution I'm really not sure where to begin! :confused:

Since the last thread got locked, how about legal means to get free electricity? One example is an AM crystal radio that receives it's power via a simple antenna. The power source is a radio stations broadcast. As posted previously, there are numerous devices like windmills or water...

supposedly u are stuck on an island battery died on your radio u have: 10 m of wire (copper?) and stuff found naturally on the island and u need to run a radio at 3 volts what would u do?:bugeye:

heres a simple question I somehow couldn't find an answer on the internet. we know radio waves only reflect (significantly) when it strikes an object with size greater than the wavelength, but I'm not sure what exactly defines the "size" of the object. For example, if I were to confine a...

Discussion: And there is very little Liberal talk radio?

hey i m kinda new at making radio controls... just made a simple RC with a 2 bit Tx- Rx kit that i got from a local shop... all my robots are wired... so i want to move on to a proper radio control(coz they don't teach RC makin in mechanical engineering:cry: :cry: ) ... can anyone suggest me...

Hello, Can you please tell where radio waves originate from? Thanks, Glynis

The tutorial on how to make a search form with multiple search options was excellent! http://www.mediacollege.com/internet/javascript/form/multi-search.html However, is it possible to use radio buttons instead of a drop-down list?Can someone be kind enough to show me the code for it...

Homework Statement Why can't you make radio transmitter that transmits visible light instead in the same way we transmith AM signals? Homework Equations The Attempt at a Solution Im thinking maybe they would not be very effective as their wavelenth is so small, they would die...

Homework Statement Compare this to the power received on the ground from a geostationary satellite with a 1 W transmitter and with a transmission footprint of 1000 square km across (assume uniform power in footprint). The Attempt at a Solution I don't know where to start on this one...

I'm not using the template here because it doesn't really suit this sort of question. Anyway, I'm writing about the Medicina Radio Observatory and I'm trying to find a site that will give me a history of the observatory. The history page provided by the IRA, which is listed as the 'official'...

hi all... Something doesn't quite add up here: A radio wave is an electromagentic wave, right. It therefore travels at the speed of light, right. Then why does it actually take a finite amount time (like secoonds or even miliseconds) to travel a couple of kilometers...

It seems that Earth is constantly being bombarded by radio waves that have been created by natural occurrences. Concerning the search for intelligent life, what sort of filter is used to disseminate between a naturally occurring radio wave and a radio wave created by intelligent life.

Are the length of radio waves relative to the scale and gravitational force of origin? In other words, if one increases, the scale of the Earth and total solar system by 10 times when this planet emits human produced radio waves, will the wavelength also be 10 times larger?

How does a Radio Antenna Work? I'm trying to get a grasp of the physical mech. You generate an AC signal on a conductor (i.e. at 30mhz) The free electrons on the skin of the conductor osc. back/forth at 30mhz. The acceleration / decleration of the free electrons causes photons to be...

Hello! I'm reading into the LHC and the "bunch structure", and I'm confused in general, and I think knowing what the radio frequency acceleration scheme is might help?! As in, how does it work? And does it actually use radio waves? Any help would be greatly appreciated! Thanks, Samantha

Hey i was wondering if someone can help me out with radios and whatnot...i know making transmitters are illegal but i was just curious as to how they work as well as receivers. The thing that confuses me is how do you get information to and from the signal? I mean if i made a tank circuit that...

For long wavelengths like radio is dense material better to block, or shield, as it is for short wavelengths like x-rays? You can block out the photons of the visible part of them electro-magnetic spectrum by pulling the curtains closed, so how come radio waves like your AM radio, cell...

I have a project in one of my classes, the aim of the project is to interface a circuit which you will design with a computer through a USB port, I read a lot about software defined radio's and I was thinking of building a very basic one which will receive AM signals and then convert them...

http://www.cbc.ca/quirks/media/2006-2007/mp3/qq-2006-09-23e.mp3"

Hey guys i was just doing a bit of poking around and i found this site. I was wondering if you lot could help me. You see i have to compare and contrast two types of similar communication. i chose AM/FM radio transmitions I know some of the bare basics like: They transmit by minipulating the...

this may be kind of dumb question but... How do XM and Sirius broadcast so many stations? Isn't evey broadcaster given one frequency.

If 10,000,000 radios are all tuned into a small local radio station, wouldn't the radio station crash, or what would happen?

I was wondering, how come with Satellite TV, I have to have a dish pointed directly at the satellite while with Satellite Radio, I can just have an antenna pointed anywhere in the sky? Is it because satellite radio is at a lower frequency or do they just push out more power?

Hi to all of you i am James i am researching about campus fm radio can anyone help me to to my research because i ask this moment i already gathered some information but i don't know how to start and can anyone give me some reference about this. thank you very much in advance.

Is there any way that I could rig an FM radio antenna to a satellite dish and pull in FM stations that are one or two hundred miles away?

with the help of an oscillator you create a frequency but how exactly do you insert the electric signal you've gained from a microphone into that frequency? if i understood the microphone right it transfers the vibrations into electrical form by altering let's say the current so that different...

If a radio station transmits at 500 kW, how does one find the electric field 25 kM away?

I was reading up on black holes when i thought of this. Black holes have been found to emit radio waves. I was wondering if this was actually light that managed to escape the black hole. Here is my thinking on this. From what i know light travels in a straight line through points through...

A spacecraft (Lo = 80 m) travels past a space station at speed 0.7c. Its radio receiver is on the tip of its nose. The space station sends a radio signal the instant the tail of the spacecraft passes the space station. (a) What is the length of the spacecraft in the reference frame...

I know that electricity can be converted to microwaves obviously. But how is it converted to radio waves?

Hi everybody, it's nice to finally join the forum. I'm a little...:rolleyes:...:confused:. Is electric current (the kind we use at home) a form of radio waves occilating at very low frequencies? What are the all the simmilarities and differences between electric current and radio waves...

Hi I have to prepare a presentation on radio frequency imaging, applications and technical aspects etc. Unfortunately the uni library has closed and my google searches appear to be coming up rather thin (more RF coils in imagers than RF imaging). Does anyone know where I could find some...

When I listen to radio, then I know that the radio gets the information from electromagnetic radio waves. But in which parameter is the information of the song/news/output/whatever included? It can't be amplitude, since amplitude decreases with distance of obstruction, and the data most...

...efficently at night time? :zzz:

An ionosonde on a satellite orbiting at 1000 km probes the topside of the F2 layer. If the ionosonde transmits radio pulses downwards at 5.6 MHz and 7.1 MHz and receives radio echoes with delay times of 2 msec and 2.667 msec respectively, determine (a) the F2 electron density at an altitude of...

I am thinking of joing up with the army when old enough, although I don't know witch branch would best suit a radio electronics based career. Anyone have any ideas?

Two radio towers are positioned 10m apart. They emit waves of 750mHz. How many maxima will you detect if you walk around the towers in a circle of radius=10m? I know that the path length difference, \Delta r , must = an integer number of wavelengths: \Delta r = n\lambda Where I'm confused...

Is there a formula to determine how much absorption of a radio wave will occur in a plasma? Does radio wave absorption depend on the pressure and temperature aside from the electron and ion density?

In a neon light, light is produced when voltage is applied to electrodes that ionize the gas in the tube. Is there any type of gas than can be ionized, and then produce light, by using radio waves as the energy source rather than electricity?

Has anyone created a radio laser, if not why not if you know...