Questions tagged [modes]
Questions related directly to the mode of communication (SSB, CW, digital, etc).
89 questions
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How a carrier wave carries sound waves
I need to know how a carrier wave carries sound waves? When any audio signal is converted to radio wave, what exactly happens?
In the case of AM, does the carrier wave or the radio wave become a clone ...
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How an Audio Signal is Modulated with FM?
An audio signal can have varying frequency and amplitude and both are the part of the information. But as per my knowledge , Frequency modulation is a technique where the frequency of the carrier wave ...
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A new ham should start with Digital or Analog Portable Radio?
I am interested in acquiring two portable radios to talk between a family member and me (both new hams), e.g. when we go trekking in a National Park or to communicate in the same city. We used PRM ...
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How does single sideband work theoretically?
How does single-sideband (SSB) work theoretically? If a theoretical SSB transceiver is a "black box" and only its inputs and outputs can be analyzed, not the way it works internally, what is ...
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How is FT8 modulated with both upper side band and FSK?
This Wiki shows FT8 mode is USB and its modulation is FSK.
I don't get the difference ...
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Can you identify the modulation of this signal?
I picked up a signal on 434 MHz (in Europe). Can you identify the modulation or give me a hint on howto analyze it further? I tried finding a similar signal on https://www.sigidwiki.com without ...
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human voice / music radio signal without RF moduation
This question is about digital voice modes that are used with AM / SSB / FM radios. Dstar , FreeDV , etc.
assumptions:
pulse width modulation amplifiers can take a digital signal as input.
a software ...
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Can a phase-modulated voice radio transmission be received and heard properly by an "FM" radio?
Not necessarily an amateur radio question (but perhaps a licensed amateur should know the answer?) - I note that the specifications for marine VHF radio operating in the 156-157 mhz band call for both ...
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Why do PSK modes have "bandwidth"?
My understanding of a naive PSK scheme is that you have some frequency(s), f(n), at baseband, and you modulate information by shifting the phase (what "point in time") the signal is at. Isn'...
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Would Orbital Angular Momentum (OAM) multiplexing work over HF bands?
OAM (Orbital Angular Momentum) Multiplexing is a form of multiplexing capable of high data speeds on limited bandwidth using the physical properties of EM waves.
An experiment in 2012 transmitted two ...
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Is this signal BFSK or BPSK?
I'm trying to analyse a signal from a HVAC remote control (864 MHz) with my HackRF, but I'm facing an interrogation about the used modulation:
Is it BFSK (frequency modulation) or BPSK (phase ...
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Why can I hear Morse when not in CW mode?
I don't "get" CW.
I can't understand the chatter on an FM radio broadcast when my radio is set to AM. This makes sense, the signal is modulated using frequency modulation and I am trying to ...
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2GFSK digital filter bandwidth calculation
I'm working on a S2LP from ST and I am configuring the RX digital filter.
I need to calculate the bandwidth of the signal which has 2GFSK modulation.
Do you think the code below is correct for ...
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What would be a good modulation scheme for communicating a single bit of information with no more than 4ms of latency?
This question has been suggested in the comments to a closed question a couple of days ago. I have nothing to do with the original question, but this aspect of the problem made me quite curious, so it ...
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NFM and FM compatibility
I read that using narrow band (NFM) when you should be using normal(FM)/wide-band(WFM) can result in the a reduced volume at the receiver.
What happens in the opposite situation? (What if you are ...
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What determines the bandwidth of an FM signal?
With an FM signal, it takes up more room in the radio spectrum presumedly because the carrier frequency is changed. On average what's the width of the FM sidebands?
Does the deviation from the center ...
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Both OOK and FSK used in the same transmission
My gas burning heating unit takes its temperature readings from a 433 MHz thermostat, which is emitting precisely the same data packets in a packet train at some ~100 ms interval like this: 2 x OOK ...
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Can an ultra-wideband system transfer data at high speed without precise clock synchronization?
Recently, ultra-wideband technology has been in the news again. From the Wikipedia article:
UWB transmissions transmit information by generating radio energy at specific time intervals and ...
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Practical limits to maintaining coherence in an HF channel
Lately I've been thinking about weak signal communication on HF. Very weak, like weaker than even WSPR could achieve.
It would be nice if one could simply take any existing modulation and slow it ...
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Is it possible to have multiple people talking on the same radio channel at the same time?
I understand that my question is not desireable for ham radio communication at all, but bear with me.
I want to use long range walkie talkies whose microphone is attached to an underground acoustic ...
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Is it practical to use a magnetic amplifier as an AM modulator in a transmitter?
If I'm building a vacuum tube HF transmitter (say, 40 m band), obviously the simplest mode to build is CW; it's common to key the oscillator input to the final (in order to keep the oscillator running ...
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Is double amplitude modulation useful?
If i amplitude modulate an AM carrier with an audio signal, can i then feed that resultant AM waveform into another modulator and amplitude modulate the AM signal to give a signal which is amplitude ...
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What exactly is a "balanced modulator"?
While studying for his U.S. General class license, my son wondered about the "balanced modulator" referred to by a few questions in the FCC pool.
Quoting KB6NU's General Class study guide to give a ...
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Peak envelope power should be 2:1 or 4:1 on meter?
I've always been reading my AM modulated signal on a Bird wattmeter and trying to set the carrier to 1/4 of the peak envelope power (PEP).
Recently, I was told by a CBer that you only can see it that ...
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How to decode a message with unknown bit rate in interstellar signal
I have a question about FSK modulation I'm going to frame in terms of a hypothetical:
Imagine that you are transmitting a message to an ET in another solar system. The message is encoded in binary ...
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How/where can I learn about ft8? [closed]
Where can I find information about the digital modes and how to get started on them? I would like a concise yet easy to understand tutorial.
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What are all the three letter codes for the different emission designators?
For example, A1A is "morse telegraphy by on-off keying". What are the others?
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Why AM modulation side bands have higher frequencies than the carrier?
I cannot understand while the AM modulations have sidebands which are of a frequency higher than the carrier. If for example we are modulating a 4kHz signal to a carrier of 1MHz how we end up with a ...
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FSK or M-PSK for weak signal communications?
Popular amateur radio "below-the-noise-floor" communication modes (such as JT65, et.al.) seem to mostly use FSK, whereas NASA's deep space network appears to use M-PSK for (extremely) weak signal ...
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Parts for a 915 MHz low power transmitter
I'm interested in doing some experimentation with custom modulation in the 915 ISM band.
Off-the-shelf radio modules use specific known modulations (FSK, QAM, etc.) so those won't work for my ...
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Why are carrier waves necessary?
I am studying for the technician exam and I have come across the section on carrier waves, basebands, and various kinds of modulation.
It makes sense to me that you create a signal by combining the ...
user11031
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Understanding WFM modulation
I am using "HDSDR" software to demodulate a WFM broadcast ("Classic FM" in the UK, on 100.1 MHz, 192 KHz bandwidth). I'm using an "SDRPlay RSP1" software defined radio and a cheap indoor discone ...
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What is the FM-N mode?
I'm reading the Icom IC-51E PLUS2 manual and it says it supports the following modes:
AM
FM
FM-N
DV
What is FM-N? I'm new to amateur radio and never heard of it before. It's not listed on Wikipedia ...
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What are the technical reasons that there are no FM transmissions on the long, medium, or shortwave?
Why are there no frequency modulated broadcasts on the long/medium/short wave, but only on VHF? I'm sure there are many historical and political reasons (long/medium/short wave were already in use for ...
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Is FM modulation still more resistant to noise when given the same bandwidth as an AM signal?
FM modulated radio is much more resistant to noise and can deliver better sound quality than AM radio. But FM signals also use more bandwidth than AM signals. In general a wider bandwidth signal is ...
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LoRa Radio RFM96/98 SX1276/8 configuration settings for Longest Range
I have a pair of HopeRF LoRa RFM98 Radio Modems(based on Semtech SX1278) and I want to configure them for the longest range possible, without taking care about any second factor like transmission time ...
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How does a transceiver work?
I recently joined my university's Cube-Sat Program and was delegated the task of looking for software that modulates and demodulates signals (~437MHz, GMSK, AX.25).
The problem now is that I don't ...
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(HF) How to maximize probability of successful transmit given constrained packet duration? [closed]
I need a HF link that will be (mostly hah) operational 24/365. Edit: at least at local daytime.
The link is supposed to transmit a controlling signal (just one bit) in one direction for quite a ...
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overly large bandwith for a FSK signal?
I am trying to recover my 2FSK signal using an SDR. I have centered the SDR modem on the median frequency (the virtual carrier) and captured my signal via some 90 kHz bw modem. THis is the recording ...
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transmitted FSK, sniffed something PSK-looking
I am transmitting a FSK signal on 433,941 ± 32 kHz at 19200 baud rate. From what I read I should be able to recover my signal with a a modem centered on my carrier and having a bandwidth of 32 × 2 + ...
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different digital modulations interference. Does it happen?
Bottom line is I have got a very strange (but regular) reading on a < $1 type of ASK 433 MHz receiver. Have a look at it - those 3 spikes are sometimes caught by my receiver, don't know their ...
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How does rpitx generate arbitrary SSB data with a clock peripheral?
While it wasn't the first to do so, the rpitx software seems to be the most active and mature implementation of what its own comments call "a code fragment by PE1NNZ". The trick is explained in Guido'...
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Air gapped digital communications mode on VHF?
According to this question MCW (modulated continuous wave) is allowed on large portions of the VHF bands in the U.S.
Is using MCW suitable for passing small amounts of digital data between 2 PCs or ...
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Which mode describes this modulation scheme
I have a modulation mode:
(to be used for a satellite)
(of a series of AX.25 frames)
(in the 70 cm band)
9.6 kbps
Ideally BPSK or QPSK modulation
but could be plain FM
Which I need to describe with ...
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How to identify type of modulation based on constellation diagram?
The constellation diagrams for a 4-ary modulation using PSK (qpsk),MSK ,QAM and OQPSK look alike. How to differentiate them?
What is the modulation for the constellation diagram in the figure?
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SSB Modulation and Differential Signaling
I'm trying to learn about how SSB modulation works. My current understanding from reading and looking at spectrum plots from SDR software is that the sound is modulated with the carrier, but only ...
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How to reverse engineer a proprietary FSK protocol
Assuming I wanted to reverse engineer 13FSK, what steps would I take to begin reverse engineering it? I have seen tools such as inspectrum and baudline that can help me view the raw signals, but I am ...
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What is Digital Mode on newer HF Transceivers
What does switching to digital mode on Yaesu Xcvr's (or any other HF radio) actually do?
The documentation states that "specific digital mode selections, which include custom BFO offsets to optimize ...
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Software TNC's for Linux? (targeted to BPSK1200)
Are there any software TNC's (like SoundModem) for Linux?
This is limited to the ones which deal with BPSK1200 (used by cubesat projects).
For some cases Warbler will suffice.
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