Questions tagged [radio]
Radio is the technology of signaling and communicating using radio waves. Consider using the rf (radio frequency) tag.
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How exactly does RF to IF conversion work in an AM radio?
I am currently researching AM radio detection circuits. From my understanding, RF is received, amplified and converted to an IF(455khz for AM) before being converted into an audible frequency for ...
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P2P communication: maximum range for low power & low bandwidth
I've started a little side project with the goal of tracking my cat's location in real time.
To transmit the GPS-data, it seems like I have two options: I can either use cellular communication or (...
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Accessing the FM 19kHz Pilot?
How can one attach an oscilloscope probe to the mono mode output of an FM station to pick up the 19kHz pilot (normally used for stereo)?
Is it expected that FM tuners such as the RDA5807 will, in mono ...
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Audio engineering: amplifying two different sources
I've started a small project to renovate/rebuild an old record player for my wife. I have a degree in Electrical Engineering, but it's been almost 15 years since I last had to project/build a circuit, ...
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How can an audio signal with varying frequency be modulated using FM? [closed]
An audio signal can have varying frequency and amplitude and both are the part of the information. As I understand it, frequency modulation is a technique where the frequency of the carrier wave is ...
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how do tube filament resistors work on this Type 10?
picture source: "Building a 1929 style TNT Transmitter", The VE7SL Radio Notebook, 2009 https://qsl.net/ve7sl/tnt.html, originally referenced from the 1929 ARRL Handbook
I don't know how ...
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Sending control signal via FM
Is it possible to send different signals to a receiver using FM which then the receiver would be able to distinguish between and do a set act based on the signal? How to?
For example, the transmitter ...
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Crystal radio antenna question
I am trying to make crystal radio.
I have almost everything I need (magnet wire, high impedance headphones, germanium diode.) The only thing I am missing is the antenna.
I know that if I want to ...
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Why do we need a diode in an AM demodulation circuit?
The incoming signal is a modulated carrier wave, right? If we only apply a low-pass filter to it, we will get an AC signal that can be passed to a speaker directly, right?
Using a diode, we end up ...
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Wideband Dipole Antenna Ideas
I am home brewing an FM radio and have this so far. It works great for stations within +-5 MHz of my antennas resonance, but I want to hear more stations farther away on the spectrum. For this reason ...
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Why can I hear a radio station when probing with oscilloscope? [duplicate]
I assembled this on a breadboard:
and am hearing a faint buzzing sound...
My first question is, what could be causing this sound? It does not go away if I connect VIN to ground. With or without VIN ...
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Difference between radio transmitter roll-off and bandwidth-time (BT) product
For any radio transmitter, the output signal will likely have a shape filter to manage bandwidth. However I am struggling to understand the relationship between a roll-off (e.g. 0.35) and a bandwidth-...
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Can two interfering light beams create radio waves?
Two sound frequencies differing in only a few hertz can create ‘beats’ and this has been popularized in music designed to produce ‘binaural beats’. Can two lasers be tuned in a similar fashion so that ...
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How to terminate a monopole antenna
There seems to be some debate on emphasizing the importance of impedance matching for maximum power transfer vs maximizing signal to noise ratio with receiving antennas. Some vote for one, some state ...
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How many independent test transceiver modules are truly required for MIMO testing?
In most if not all of the app notes I have ever seen from the major test equipment vendors, such as R&S and Keysight, it is strongly implied if not explicitly stated that in order to do an NxN ...
