Questions related directly to the mode of communication (SSB, CW, digital, etc).
Questions related directly to the mode of communication: ssb, fm, am, cw, digital-modes, etc.
Questions tagged [modes]
87 questions
64
votes
18 answers
Why is Morse code still in use?
Why do people still use Morse code?
What are its advantages over newer voice or data communication modes?
Timtech
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14
votes
4 answers
Is is possible to operate D-Star from a software-defined radio?
What is preventing a software-defined radio from transmitting the D-Star protocol?
Paul V
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13
votes
3 answers
What is the role of digital data modes in emergency communications?
Emergency operations are typically reliant on voice traffic today. Are digital data modes used at all in emergency operations, and why/ why not? Couldn't data modes be used to pass information more efficiently than voice?
JC Hulce
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12
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2 answers
What does a SSB frequency actually indicate?
An SSB signal is an AM signal with the carrier and other sideband filtered out, if I understand correctly.
As such, when specifying an SSB frequency do you specify the carrier frequency, then state which sideband, or do you specify the frequency the…
Adam Davis
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11
votes
1 answer
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 more resistant to noise / can send more data than a…
JanKanis
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11
votes
1 answer
Why does AM have sidebands?
Why does AM have sidebands? Isn't the whole point of AM to broadcast on ONE frequency and ONLY change the amplitude?
In the picture there is only ONE frequency and the amplitude changes, so why got AM sidebands? And why can't AM work without the…
Axel H.
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11
votes
6 answers
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 down to achieve an arbitrarily high Eb/N0 and thus,…
Phil Frost - W8II
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10
votes
3 answers
Does modulation affect propagation?
Does the modulation scheme, whether OOK, SSB, AM, FM, a digital mode, etc, affect the propagation of a signal?
Adam Davis
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9
votes
1 answer
How does SDR demodulation differ between wideband and narrowband FM?
What is the difference between software demodulation of an IQ signal between wideband FM and narrowband FM? Both seem to look at the 2nd difference in unwrapped phase angles of IQ samples.
hotpaw2
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8
votes
2 answers
How do I notify and publish information on experimental modes?
I'm considering tinkering with a new mode. Of course I'll stick to experimental channels and low power for now, but as people notice my transmissions they won't immediately understand what is being transmitted.
How do I disseminate information that…
Adam Davis
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8
votes
1 answer
Is FM appropriate for foxhunting?
I'm thinking about an inexpensive way to create a foxhunt kit for youth groups, and am wondering if the cheap dual band HTs could be used.
However, it occurs to me that FM doesn't provide any good audio queues for signal strength, and the SWR meters…
Adam Davis
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8
votes
2 answers
HF Digital Mode Band Plan for the USA
I recently started playing with the digital modes, but have been frustrated with the difficulty in finding where certain modes are commonly used. Is there a digital mode band plan for the HF bands, to the level of which modes are commonly used on…
PearsonArtPhoto
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8
votes
3 answers
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 sense of the two questions:
Filters are also used…
natevw - AF7TB
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7
votes
2 answers
Does AM demodulation make use of the redundant information in both sidebands to eliminate noise?
XLR microphone cables, for example, make use of the dual channels out of phase to cancel noise by injecting the inverted and non-inverted signal into one end of the cable. Then any noise injected along the way will presumably be equal, and…
Bill - K5WL
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7
votes
4 answers
Is frequency hopping a viable solution for privacy and security without encryption?
In terms of radio transmission, three major issues seem to arise for various sensitive transmissions:
Others do not gain access to the content of the message
Others cannot determine the location of the sender
Others cannot block (jam) message…
J-S
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