Radio Definition and 691 Threads

Hello! I have been thinking of broadcasting a message into outer space. It sounds silly, I know, but that's just something I'd like to do for and with my niece. She's 8 years old and very interested in physics (as far as she understands it). I have some knowledge in electronics, I think I...

helo can somebody tell me how does work this circuits please, calculations and the rest

Hello. I'm an English language teacher researching the details of a class project; I use projects to develop language skills. I have a background in mechanical engineering but know little to nothing of electrical engineering, hence this post. Questions for members of this forum: Electrical...

Hello. I have been interested in radios lately and wanted to make one by myself. I know that it requires a lot of knowledge in physics and electronics, but what basics do I need to know? Frequency, antennas, voltages... Could there be any legal issues? I live in Australia. I am only a high...

Hi there! I'm looking to create a small (max 20 foot range) radio transmitter, to direct a focused radio beam at a receiver, for the purpose of remote switching. Ideally, I would like the device to work at a relatively "exotic" frequency, as I would think there is a lot of radio noise where I...

when it is asked that why radio waves do not interact with the magnetic field of electric wires or magnets, people say that radio waves are not "matter" and they do not have "charge". i really can not understand this for ex think about 2 magnets. The magnet A has a magnetic field and when we put...

Hello, I am interested in making a homemade radio receiver out of common materials. Do you have any suggestions or websites I could get some ideas from? Thanks. I.

Hi all, Is there any way to impart a transformation upon a radio wave's reflection from an object, such that the reflected wave is different from the original signal in some way (frequency, phase, etc.)? Not sure what this would require (maybe a constant and active coordinated interference...

How useful are non-navigational radio beacons (i.e., for determining current propagation conditions and testing) nowadays, whether microwave X band, HF, ELF, sub-mm wave, etc., considering the advent of computerized propagation modeling? Is the scarcity of non-amateur radio beacons a result of...

Homework Statement July 22,2017. Homework Statement Television and radio waves can reflect from nearby mountains or from airplanes. Such relfections can interfere with the direct signal from the station. a. Determine what kind of interference will occur when 75-MHz television signals arrive at...

Couldnt we put lcd type filters into orbit and modulate sun/moon light to produce high definition radio/tv? Obviously it would need to be large but it seems like it wpuld be much more efficient.

Could somebody explain me why it would not be sufficient for a radio receiver of an AM signal to simply consist in two elements: A very long antenna. A speaker/headphones. The set up would be as follows, the antenna is connected to the speaker and the other part of the speaker is grounded. My...

I seem to have a lot of trouble understanding radio carrier signals I have read a bunch of stuff online and seen videos trying to explain it but I just can't understand it! Could some of you who understand try and give me some analogies or anything that might help me out? Thanks alot!

EE, and life-long science explorer and tinkerer. I look forward to reading the forum, and hopefully contributing at some point. This looks like a great forum! If we weren't limited to 5 tags here, these would have been mine: physics (duh!), relativity, nuclear, antennas, time, radio...

This appears to be a New Scientist scoop: Fast Radio Burst Pinned Down to Giant Stellar Nursery by Ken Croswell A young neutron star is probably the source of a repeating signal previously tracked to a dwarf galaxy 2.4 billion light-years away. Link: New Scientist

Hello - Not sure if this is the correct location for this. I've been thinking about how a radio wave would work as the transmitter travels further away from the receiver. My example is a transmitter on a spaceship traveling 60,000 kph that transmits a loop of my favorite playlist back to...

Hi friends in my class we had to study some topics out of our interest .. i tried for along time to understand them but the teacher's slides is not enough for understanding so i ask if anyone can give me sources to study the topics (the same way ) which attached as a photo note : i studied...

hello folks. 1.its possible to change simple analog radio device (reciever) to cosmos radio waves reciever or just cosmos radio with relativy small price. if you know how please ilustrate it with images, thank you very much.

Hi! What exactly makes electrons in the antenna move to generate an induced current which then can be encoded? Is it radio waves that hits the antenna and makes the electrons move? If so, why/how? :) All I get from this link is that "the radio waves makes the electrons wiggling back and...

According to the old thery of light the energy carried by by a wave is proportional to the amplitude of the electric field not to the frequency as Planck proposed, so an eletromagnetic radiation in the gamma spectrum carry the same energy as a radio one if their amplitude is the same? They only...

Homework Statement You are building a simple passive AM radio using a series RLC circuit with an voltage source of V sin(omega*t) and the voltage drop V_R across the resistor as the system response. You would like to know the relations between the values of R,L,and C in order to tune to a...

Hello Experts, This is @Shubham Jaydeokar, and today I'm going to post a question regarding a software named Space Radio. I have been working on my project of making a receiving setup for listening to the audio signals sent by ISS at 145.800MHz. According to AA2TX@amsat.org, Anthony Monteiro, I...

I stopped by Radio Shack and picked up some parts since they're going out of business. I bought mainly plugs and connectors but also a soldering iron and some 50 Ω coaxial cables. Normal price total would have been $104.28. Out of business price total w/tax was $30.57. They're open half a...

I recently got a 5 cm high radio tube from a old radio in my house. It has 9 pins ,arranged in a C shape at the base, a getter at the top and parallel metal plates inside. I decided to use my GMC-300E plus ,Geiger counter to check if it had a thoriated cathode. It did not. Just for fun, I two...

This paper; https://arxiv.org/abs/1702.03301, A VLA Search for Radio Signals from M31 and M33, discusses the results [null] of a VLA search for narrow band radio emissions from the Andromeda and Triangulum galaxies. The focus was on narrow band signals because these are the only radio signals...

I have learned that the Doppler effect causes a change in wavelength (and thus frequency) in all types of waves Suppose there is a radio station transmitting waves of frequency 90 kHz and the antennae in my car is tuned to that frequency. Then I start to accelerate and thus I am changing my...

I know that the trend in commercial radio is towards digital. Suppose we go to all digital radio. My question is specifically about amateur radio. Will it still be legally possible for HAMs to operate analog radio systems? Any indications at all from the FCC or similar bodies outside the USA on...

hello people . i don't know if this is the right place to ask , but I'm studding for my cisco ccna and now I'm learning more about radio waves and wifi networks and i fall in love with the subject , what i don't understand is what's the difference between a radio and a antenna , because i asked...

Homework Statement Flat harmonic electromagnetic wave propagates in the positive direction in vacuo axis y. Vector electromagnetic energy flux density is given by: S(y,t)=Sm *cos(wt-ky)2.Wave value: k=(2*π)/λ=0.41 m-1,Amplitude Sm=26 W/m2.Compare this wave with another wave. Homework Equations...

Hi there, My name is Kathy and I am writing a book about the history of electrical discoveries. I am writing the book for adults who have limited (or no) science backgrounds with a lot of personal details (like Bose who liked to give electric kisses to attractive women, or Alexander Bell's...

I've been reading about this interesting topic today. So the first radio signals emitted from the Earth are about 110 light years away from Earth now. Most authors point out that an advanced alien civilization only 125 light years away would have no idea of our existence. Fair enough, but the...

I am building a project where an object will be fitted with an RF transceiver and where it will face wooden walls as obstacles, with constant thickness "t". I am trying to look for an equation that would give the appropriate radio frequency that I would need to generate to have a radio wave...

Homework Statement Suppose you want to use a series RLC circuit to tune in your favorite AM radio station which broadcasts at a frequency of 1.20 MHz. You would like to avoid the obnoxious easy listening station which broadcasts at 1.10 MHz, right next to the one you like. In order to achieve...

When antenna receive the radio signal does it reduce the actual radio signal strength or strength indeed depends on the dispersion loss and other dielectric absorption? If antenna doesn’t reduce the radio signal strength(power), how it generates the current in the receiving antenna circuit? How...

Homework Statement A radio broadcast antenna is located at the top of a steep tall mountain. The antenna is broadcasting 104.3 FM (in Megahertz) with a power of 5.00 kilowatts. What is the peak intensity of the signal at a receiving antenna located 25.0 km away? Homework Equations Honestly...

Hi All, I was wondering if someone could answer these questions for me please? Q1. If I stuck an antenna out, will it receive all the different signals e.g. Music Radio, TETRA, WiFi? Q2. What is the difference between these? I thought it was the frequency e.g. TETRA uses 300-400 MHz, WiFi uses...

i have noticed in several geographically diverse locations, drastic changes in FM radio and WiFi radio communications at the time of sunrise/sunset plus/minus a few minutes. But soon after the rise/set, they return to normal. Other frequencies, like cell phone reception seem unaffected. I...

When, in wireless communications, does the inverse fourth power-law become relevant? My understanding is that is that what cause the average signal power to degrade to the forth power is cancellation from self reflections. So by my way of thinking, an LOS point to point system, like a...

The higgs field is everywhere.. how do you use it in a 2 way communication radio so the United States can communicate with the other side of the planet by passing right thru the mantle and core without using any satellite relay station?

Hello PF, I was wondering if there is any good guide to build a radio telescope that can give me an image not just a graph. I am just a starter so any advice or tips are relly appreciated.

So I have basic knowledge of radio waves and how they work but how does an amplifier boost the signal? Does it just make the waves stronger (if so how) or does it effect another aspect of the radio wave? Thanks in advance for the assistance.

A source that is orbiting close to a singularity of a black hole is transmitting a radio frequency signal that lasts 60 seconds and is repeated infinitely. The signal is being transmitted using the amplitude modulation method (AM Radio). Let suppose that each minute passing in the transmitting...

World's largest radiotelescope just completed. http://news.xinhuanet.com/english/2016-07/03/c_135485643.htm

I'm pretty darn new to engineering, so I'm just diving in and hoping all goes well. I've got roughly 6 months to finish this project as it's a Christmas gift in the making. My current plan is to carve a large spruce log into the shape of an old cathedral style antique radio, make a cabinet...

I know sometimes speakers/amps will pick up a radio signal. I'm confused as to how the signal is demodulated accidentally. Are the signals picked up exclusively AM, or do FM signals get picked up as well?

Hi Me and a couple of class mates are working on our bachelor's project of which the mission is to measure the temperature of the sun using a parabolic antenna. We are having great troubles trying to come up with an equation relating the antenna temperature (which we are able to calculate with...

How telecommunications work? I mean, there are so much waves around us nowadays, how my cellphone recognizes a single signal and rings only when it detects it? If my cellphone is a receipter, why can't I listen to my neighbor converstation, why isn't there a lot of interference and how waves...

Not sure if this is the right section or if this might be better off over at Cosmology... or...? So this is actually around a story concept I had, and while I would like to get the science as right as possible, I expect a certain amount of hand-waving to get past some of the difficult and...

I would like to get an, if possible, detailed analysis of the phenomenon by which you hear a noise in your radio speakers when the home lights are switched off. It probably has to do with a wave packet emitted due to switching off the lights, which is picked up by the antenna of a conventional...

Hey, I'm learning about DSB and SSB in my communications classes and I'm a little confused with the concept. So, We know that in a AM signal there is the Modulating signal (Information) and the Carrier signal (Transmission signal.) We also knows LSB and USB are created when the signals are...