# What is Radio frequency: Definition and 44 Discussions

Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around 20 kHz to around 300 GHz. This is roughly between the upper limit of audio frequencies and the lower limit of infrared frequencies; these are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves. Different sources specify different upper and lower bounds for the frequency range.

View More On Wikipedia.org
1. ### Studying Critique My Self-Study Schedule (Signal Processing & RF Electronics)

Hello everybody. I have already graduated I am currently in training at work which I am required to finish intensive courses. So I will start when it's completed. My interests are in Signal Processing & RF Electronics which you could tell by the study plan I created. I will be taking a slow...
2. ### Specific Absorption Rate(SAR) - caused from radio frequency from mobile phones

Why SAR value at body is allways higher than at head?
3. ### Radio frequency shielding for Raspberry Pi Zero

So I'm trying to put together a Pi Zero mini computer to use for security-oriented applications, for example encrypting/decrypting messages, working with encryption keys, etc. It's cheap, very small and thus easy to carry around. However, I'm not entirely comfortable with the presence of the...
4. ### Plasma ball radio-frequency energy

I read Wikipedia's description of how a plasma ball works. Question: What kind of energy is the "radio-frequency energy from the transformer"? Is in the form of electric field energy, magnetic field energy, or both? Thank you! (from Wikipedia)... Although many variations exist, a plasma lamp is...
5. ### Radio Frequency Acceleration in Particle Accelerators

So, I've been really interested in Particle Physics since 6th grade when I did a project on particle accelerators. I understand most of it, except for one thing, the radio frequency cavities which are used for acceleration. I just want to ask, how do the Superconducting Radio Frequency Cavities...
6. ### Easy way to calculate losses for re-purposing a transformer?

Hi everyone! This is my first thread :) I've been working a bit with AC and radio, and would like to make a simple(-ish) circuit in which a 1-volt peak audio signal is stepped up to around 5 volts with a transformer, and is fed into a crystal oscillator to make a crude-but-effective AM...
7. ### Creating a Multi-Radio Wave Demonstration: How to Find the Right Machine

Is there a machine that can emit multiple radio waves simultaneously? I am trying to create a demonstration, but it requires multiple radio waves at once and cannot find any machines that can do so.
8. ### I Why don't we ever hear about low-frequency photons?

We're told that all electromagnetic radiation consists of photons. But you never hear them mentioned when discussing low-frequency radio waves. Why not? I get that, due to the low frequencies, the energy of each individual photon would be very small, so there must be lots and lots of them flying...
9. ### Can a radio frequency be lowered by a passive circuit?

Is it possible to design an unpowered antenna, (possibly some kind of RLC circuit) which will receive a radio wave at a particular frequency and then re-emit it at a lower frequency?
10. ### Counting clicks (signals) at a radio frequency receoved by a shortwave radio

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...
11. ### Properties of RF harmonics

How can the power/amplitude of a particular RF harmonic be calculated? I would assume it is some well-defined fraction of the amplitude of the main frequency? Do RF harmonics from a square-wave drive appear only on the even, odd, or both, multiples of the base frequency? How do high-frequency...

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...
13. ### Determining the Correct Radio Frequency

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...

Hello, I am just wondering whether it is theoretically possible to create radio waves through bioluminescence. I realize that most organisms produce only UV to infrared light. Are there such compounds out there that would allow an organism to make radio waves instead?
15. ### What Forces Cause Rotational Emissions?

I was curious about what forces can be applied to a molecule to cause a rotational emission.
16. ### Logitech X-530 - AM radio frequency

I have poorly made computer speakers - Logitech X-530. They sometimes pick up AM radio stations and pops up when lightning is turned off. What AM radio frequency is picked up by computer speakers? I am curious becaous some kinds of popping is picked up by computer speakers but it is not picked...
17. ### RF Energy Harvester: Villard Circuit, Supercapacitor 3.7V 2000mAh

I am using RF energy harvester circuit to charge mobile in my project.The rectification part is done by Villard Voltage multiplier circuit .I need to used a supercapacitor to store the harvested energy .As the battery rating of the mobile phone is 3.7V and 2000mAh.So can i use 0.33 Farad 5 Volt...
18. ### Understanding propagation loss: What does this output mean?

Hi there! I am currently building a simulation to model the propagation of radio waves in seawater in terms of its propagation loss. I have previously discussed the models I've looked at but have settled on a model which depends primarily on the propagation distance ##r##, the carrier wave...
19. ### How is radio wave propagation modelled in seawater?

Before I start, I apologise for the information dump that is to follow. I don't expect all questions to be answered or all models to be addressed; I simply feel it is appropriate to provide the community with my current knowledge and stage of research so you may not have to search for it...
20. ### Quantum fluctuations at radio frequencies

Hi. I'd like to learn how to calculate the probability of a photon being emitted from a radio antenna where the energy per wavelength is below the threshold to emit photons. Let's assume the electrical thermal noise is insignificant. The antenna temperature could be sufficient low or the...

Homework Statement A coaxial transmission line consists of an inner cylindrical conductor of radius 1mm and a cylindrical outer conductor chosen to make the characteristic impedance 75 ohms. The space between the conductors is filled with a gas that can stand a maximum field of 10^5 Vm^-1...
22. ### Radio Frequency Interference in Cell Phone

I'm trying to find out what material might best block or limit radio frequency interference (or at least I think that's the problem, as I understand it). I have a phone, the antenna inside the phone is next to a chip that controls a touch button. Whenever the phone boosts the signal to...
23. ### Medical Electrophysiology Radio frequency Ablation Question

I am interested in the medical field of electrophysiology and I have a few questions regarding the procedures done on patients with atrial fibrillation. What is the purpose of radio frequency ablation on the tissue of the heart? How does damaging the tissue relieve atrial fibrillation...
24. ### Radio frequency amplifier and error rate

Hi, I am designing an RF link. Before my spectrum analyzer, I have an RF low noise amp with a NF of 2.5 dB. Without this amplifier, my error vector magnitude or error rate is 2.1%, after an amplifier it goes down to 0.7%. My question is, the receiving signal will have its own SNR and with...
25. ### Radio Frequency Interference (RFI)

I am an electronics technician, and I work on various types of electronic equipment including radio communications devices which is the reason for asking this question. I was recently troubleshooting a radio communications malfunction, basically when squelch was broken, there was a “noise”...
26. ### Materials that radio frequency EM waves can penetrate

Can radio waves penetrate steel? What about titanium? Maybe a characterization of what they can't penetrate would be more informative? ...Or a way to figure out what materials they can penetrate. Thanks, Jake
27. ### Where Can I Find Information on Radio Frequency Antennas for Amateur Radio?

could anyone help me by giving information about radio frequency antennas if possible provide me powerpoint pesentation

What does it mean physically when radio stations mix? As in if you are listening to one station, but you begin to here another and eventually only here the wrong station.

31. ### Construction Cranes Radio Frequency Induction

Can anyone explain why cranes in construction sometimes experience induced currents from antennas radiating from distances of up to several Kilometers. I have looked into the phenomenon several times, and have not been able to find a study or baselines to follow. I have a basic understanding...
32. ### Writing information to Radio Frequency Identification(RFID) tags

Good day, I have been given the task to create an inventory database for the books at the library at my school using the RFID to monitor the books. However the books have specific codes based on their type and location in the library. I was wondering if someone could give me some information as...
33. ### Simultaneous radio frequency energy reception

Regarding the concept of radio frequency interference, electromagnetic waves, as broadcast, never actually interfere with each other. The interference exists as interference to the induction measured at the receiving antenna. So my question is, has anyone ever tried to produce an intelligent...
34. ### Radio frequency creating light

hi guys , I d like to ask you some comments and recommendations, I am an undergrad working ,trying to, on a project. I was thinking that if I could connect an antenna to a prism and then create light of different wavelength which could be used for ...I don t know photoelectric effect and...
35. ### Radio Frequency and electrical signals

"Radio frequency (RF) is a rate of oscillation in the range of about 30 kHz to 300 GHz, which corresponds to the frequency of electrical signals normally used to produce and detect radio waves." - Quoted from Wikipedia. How can electrical signals be used to produce and detect radio waves...

(Sorry if this is off-topic for this group. There's really no group that addresses accelerators in the Physics Forums) I've looked at many examples of RFQ linear accelerators. Most of them share the same characteristics: 1. So-called vane electrodes 2. Opposite-facing electrodes...

Homework Statement Build an AM/FM radio. Determine the frequency and wavelength of the radio wave for best reception. 2. The attempt at a solution I have built a AM/FM radio. My only problem is how do I determine the optimum frequency for best reception? I have only one solution and...

Hello. I'm trying to understand electromagnetic radiation. Any help would be appreciated. From my understanding a photon is a basic "unit" of electromagnetic radiation with an energy corresponding to hv. Additionally radios transmit electromagnetic waves by sending an AC through an...
39. ### Radio frequency selection problem

Hello everybody. As I'm new here, maybe someone can help or direct me to other resources that will assist in my investigation. I am looking for information that can help me select the proper radio frequency for use in a new project. The following is an overview of the project and the...
40. ### Convert radio frequency to temperature

Hello, Is there a formula to convert a certain radio frequency to temperature? Thanks.