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1answer
28 views

RF disturbances produced by transmission power lines

I need a book or paper that contains "the effects of transmission lines on the radio frequency transmission and disturbances". Could you help me find a useful textbook? Thank you
0
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2answers
49 views

materials that can render Bluetooth useless

i'm currently preparing some experiments about using Bluetooth in real life. And to make the data more vary, i need some materials that can really giving side effects to Bluetooth functionality. i've ...
0
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0answers
23 views

How to describe frequency spectrum with samples?

I posted this same question in math, but nobody is answering, so I thought I'd give a try here too... To me the question is pretty straightforward, but nevertheless I have to explain its background ...
2
votes
1answer
22 views

How do NFC/RFID devices transmit data?

I am designing an NFC device but am still a little unsure about the principles behind NFC/RFID. From what I understand: A primary coil constantly emits a 'carrier frequency' magnetic field. This ...
1
vote
1answer
44 views

Light / TEM wave in a hollow waveguide

I'm cramming for my EMF exam, and a question came up: Light in free space is an example for a TEM wave, isn't it? (Maybe thats already my mistake) And we learned that in a hollow waveguide only TE ...
0
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1answer
74 views

Cantenna and waveguide

I'm studying for a lecture of RF and wave guides and i'm currently building a cantenna. I have two questions about it construction and on how it works. My questions are about the lengths of the ...
1
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1answer
88 views

Do neutron stars produce sound?

I've watched a video on youtube about neutron stars as called (pulsar) and it claims that pulsars produce this sound. then i found that they produce radio waves which can be converted to sound. Radio ...
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0answers
17 views

My microwave oven disrupts my bluetooth connection even when I'm 12ft away. Should I be worried? [duplicate]

I often wear bluetooth headphones that connect to my mobile phone. I work on my laptop in my dining room approx. 12ft away from the microwave oven and my mobile phone is usually in my pocket; ...
0
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1answer
96 views

Do Sidebands mean the frequency of an AM radio wave is not constant?

I'm studying for A-level now..... I have read some other posts explaining how the sidebands generated after the carrier wave is modulated. So, if there is sideband frequency, the frequency isn't ...
0
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1answer
45 views

Building a Crystal Radio Questions

I have been reading several books and articles about building a crystal radio and the explanations about the inner workings of the circuit seem vague. All articles and books mention the coil and the ...
0
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0answers
29 views

Biological Signal Extraction Methods

EEG / MEG Back in 1929 Hans Berger recorded the first electrical potential variations in the brain from the scalp. Great advances have been made in this science since discover, with many scientists ...
0
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0answers
48 views

Discernible “frequencies” of magnetic fields that do not affect each other

Two magnets secured to a surface close to each other in a fashion such that their constant attraction to one another is counteracted by the normal force of the securement of each. Is there a way to ...
4
votes
1answer
122 views

Why does a non-contact voltage detector light up when you touch a plasma ball with the other hand?

I am doing a science experiment and we decided to try holding a non-contact voltage detector up to plasma ball. We were surprised that it would light up when it was 3 ft away from the plasma ball. I ...
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0answers
15 views

Transmitting to and from low earth orbit?

I'm a hobbyist and I'm currently thinking about building a Cubesat. I'm currently designing PCBs, casing, etc. I was wondering what variables are involved with sending data to and from 250km - 350km ...
1
vote
1answer
85 views

Does rain jam radio signal?

I have experienced several times that heavy rain seems to jam the signal a radio of a bus receives. The only explanation I have is that the rain drops also become weak emitters, if a radio wave hits ...
0
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0answers
28 views

Ground influence on 434 MHz radio signal

I have read in a paper that ground acts as reflector for radio signals in 434 MHz band. Why is that the case?
0
votes
1answer
48 views

How is spectrum controlled? [closed]

I understand that spectrum is considered a national resource for many governments. It is akin to land, water and other resources. It is also a scarce resource. I wonder how is it that government ...
1
vote
1answer
93 views

polarization of a transverse wave travelling in ionosphere with polarization direction perpendicular to earths magnetic field

Assume a transverse electromagnetic wave entering ionosphere such that its Electric field of wave is perpendicular to earths magnetic field. Now, i read that as it will enter plasma, the wave will ...
0
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2answers
42 views

Chaff-RF Relationship?

What is the relationship between chaff length and the frequency it is meant to interfere with? I've read that specific lengths of chaff are more effective as a countermeasure for specific ...
2
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1answer
126 views

Radio wave propagation in ionosphere

Radio communication is based on the concept that a radio signal incident on the ionosphere is reflected if the frequency of the wave matches the plasma frequency. But what exactly happens? Is it ...
2
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1answer
62 views

The influence of the antenna height

I am working on a model of a transmitter. The transmitter is attached to the wheel of the vehicle and thus constantly changes it's height. In other words capacitance between antenna and ground is ...
0
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2answers
31 views

Radioactivity features

What happens if someone would make a wire coil around nuclear reactor core? What are the possibility to capture radioactivity directly?
0
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0answers
35 views

Why can microwave (in microwave oven) heat the food but wifi can't? [duplicate]

As far as i know, microwave (used in microwave oven) and wifi all operate on the same frequency, but why microwave can heat the foods while wifi wave can't?
2
votes
3answers
2k views

How does the movement of electrons produce radio waves?

I'm mostly wondering about radio frequencies. I understand that voltage is the movement of electrons, and that the antenna acts as a light bulb, emitting at radio frequencies, following the reverse ...
3
votes
2answers
2k views

Why is bandwidth, range of frequencies, important when sending wave signals, such as in radio?

So in wired/wireless networking and radio, signals are sent in form of wave. Then the concept of bandwidth comes in, which is the difference between highest frequency and lowest frequency in a signal. ...
4
votes
1answer
145 views

AM Receiver and sideband frequencies

How sorry for "dummy" question. I have difficulty to understand how the AM receiver. Being a child I was taught that AM receiver resonates only with the radio frequencies it is tuned to, and "passes" ...
4
votes
1answer
196 views

Does any lower frequency electromagnetic radiation naturally reach us from the Sun?

I am not sure whether the sun originally emits everything in the electromagnetic spectrum, (whatever the relative strengths of each portion might be), but I do read that many waves, including gamma / ...
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3answers
467 views

Do radio waves interact with electrical wiring?

AFAIK radio waves can be influenced by magnetic fields (when not traveling through a vacuum). Electrical wires create a magnetic field perpendicular to the length of the wire, as a function of the ...
3
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2answers
286 views

What does an analog voice transmission look like in the visible spectrum?

Analog radio signals are transmitted using light in the radio area of the spectrum. If it was transmitted using the visible spectrum instead (using a visible light emitting device instead of a radio ...
4
votes
2answers
247 views

What is happening to the electrons, and E & H fields, in an antenna with a standing wave inside?

Diagrams like the one shown below are often shown to explain antenna theory, but I have always had problem with the concept of voltage being a wave, and because of this the diagrams never make any ...
2
votes
1answer
173 views

Shielding RFID with aluminium foil

I've been playing around with some contactless bank cards and an RFID reader app on my phone. As expected, if I wrap the card in foil, the reader no longer detects it. But I was surprised to find that ...
1
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0answers
33 views

Which power should a radio transmitter have to overcome attenuation of 100 km thick ice crust?

Imagine I put a floating probe inside the subglacial ocean of Encelado or Europa: how much power should my radio have to be able to communicate from external surface with the probe? Or, in different ...
1
vote
0answers
122 views

Can I detect/measure strength of a FM radio wave using a Electro magnetic field meter?

I understand that an alternating current produces an Electro magnetic field . The strength of this magnetic field can be measured by measuring devices. What I wanted to understand is Are the FM ...
0
votes
1answer
78 views

Radiofrequency attenuation in cold plasma

The missile plume can be considered a cold plasma. If a radio signal passes across the plume it's attenuated. Obviously the attenuation depends on the frequency of the signal. Where can I find some ...
0
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0answers
78 views

High Frequency radio wave propagation time

What is the maximum time for an HF radio wave to reach its destination regardless of propagation mode? Since electromagnetic waves' speed is close to the light speed in the air, can we say it is ...
1
vote
3answers
236 views

Are communications between computers faster by electrical signals via copper cables or electromagnetic signals?

Assume that there are two computers which are connected with a copper cable, e.g. Ethernet. Also, there is a radio connection between them, e.g. AM radio, in order to exchange data. When we try to ...
1
vote
1answer
391 views

What is Rabi nutation in NMR?

What is the mathematical and physical significance of Rabi Nutation in terms of NMR?
4
votes
1answer
277 views

Do higher frequency EM waves travel longer than lower EM frequency waves?

In radio communication, the distance traveling seems to be an important parameter before we choose the frequency band of communication. There is also a path-loss model that describes a distance ...
0
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0answers
58 views

Frequency response of the wireless channel

We know that the signal attenuates out with distance and according to the channel transfer function or frequency response, the signal frequency components attenuate to different values based on ...
1
vote
1answer
115 views

Transparency of gypsum and concrete for RF waves

Is there a database (or any other source) of graphs of average transparency of various materials (cardboard, concrete, gypsum etc.) as a function of wavelength?
2
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2answers
361 views

Radio Transmission distance (FM) [duplicate]

I am trying to find a formula (if one exists, and this is the right place) to try and calculate how far a radio station can transmit, under ideal conditions. I have searched Google, and I can not find ...
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votes
4answers
3k views

How can light carry data if light has no mass, and data has mass? [closed]

Via a packet-switched network, like the internet, data is sent as packets (bits) wirelessly via radio waves with Wi-Fi, or 802.11g, etc. What my question is is this: Radio waves are light; light has ...
2
votes
1answer
140 views

Is there a way to tell what frequency an unmarked antenna is designed for?

I have accumulated a large amount of R/C gear over the years. I have several antennas which are not labelled as to their original use. This antenna is either for 5.8ghz, 2.4ghz, or 910mhz. The ...
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vote
0answers
52 views

Does shadow fading change if obstacles are fixed?

Given a RF sender and a receiver, suppose the obstacles between them are fixed, both their material and dielectric properties, does the path loss caused by their shadowing vary? If yes, what causes ...
2
votes
1answer
329 views

RF WiFi Radiation

I would like to extrapolate my current router wifi radiation from my phone. If I know that my router is transmitting at 300mW and my phone displays the strength in -dbm (from 0 to -100 scale) if I ...
0
votes
1answer
2k views

How do EM waves get detached from an antenna?

How does an electro-magnetic waves get detached from an antenna and spread to the space? While an antenna receives an EM wave, which quantity of the EM wave (electric or magnetic) is used for ...
0
votes
1answer
382 views

Is it possible to make an RFID-like device which responds to a metal detector?

Would it be possible to make a small device which can be easily detected with a metal detector (or similar) from several feet away? It would need to operate kind of like a shop-security tag but it ...
2
votes
2answers
1k views

How is antenna gain correlated to beam width?

Let's say you have two dipole type antennas. Antenna A has a gain of 2.15 dBi, a horizontal beam width of 360 deg and a vertical beam width of 45 deg. Antenna B is similar to antenna A, but has a ...
1
vote
1answer
325 views

A comprehensive reference for RF linear accelerator's operation

I'm doing a research on RF linear accelerators (RF Linac), but while studying the material I encountered many problems. I cannot understand the basics of the RF linear accelerators in many ways, for ...
6
votes
2answers
198 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 ...