Questions tagged [modes]

Questions related directly to the mode of communication (SSB, CW, digital, etc).

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5
votes
2answers
201 views

Frequency Modulated Light

I've been doing a bit of work on optical open-air transmission, and have been thinking, any hays that varies the intensity of the light or whatever else would affect the amplitude. Would it be ...
2
votes
1answer
177 views

What modes are used for transmitting motion pictures video?

SSTV permits transmission of single images, or if one desires image sequences at a very low framerate. Are there specific Amateur Modes that are meant for real time (motion pictures) video ...
1
vote
1answer
85 views

Can I filter after modulation when using a square wave oscillator? [closed]

Most designs appear to filter most of the harmonics out of the oscillator before modulation, then apply additional filtering as needed for the specific modulation they are using after modulation. ...
5
votes
5answers
2k views

What about the digital mode ROS causes some to consider it spread spectrum?

The FCC disallows amateur spread spectrum communications below 220MHz. At the moment the relatively new digital mode, ROS, is considered, by some, to be spread spectrum. So this mode is getting ...
4
votes
1answer
412 views

What is this short, wide band signal?

I've observed a signal I'm unfamiliar with, and am wondering what it might be: The period of time it lasted is 5 seconds, and it occurs irregularly. You might be able to see it too via WebSDR. How ...
6
votes
2answers
116 views

Is CW necessary to be competitive in most ARRL contests?

The ARRL hosts many contests throughout the year, and maintains a leaderboard of sorts to encourage competition. Is it possible to rank on any of the leaderboards without knowing or using morse code?
3
votes
2answers
232 views

HD quality voice?

Are there any existing codecs or modes, or are hams experimenting with modes that provide better than telephone/radio quality sound? It seems like there's a lot of opportunity here to stick to narrow ...
5
votes
4answers
420 views

Is there such a thing as a phase modulation voice signal?

Wikipedia indicates that in the digital domain ASK, FSK, and PSK are common. It seems that only AM and FM are used for analog forms of communication. Why don't we use Phase Modulation techniques, ...
6
votes
2answers
640 views

1200 baud packet radio can't communicate

I'm toying with a simple 1200 baud packet radio I built. I'm attempting for it to be compatible with APRS, which uses the Bell 202 signaling, 1200Hz for mark and 2200Hz for space, which I assume map ...
8
votes
2answers
134 views

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 ...
11
votes
2answers
726 views

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 ...
6
votes
1answer
224 views

Why do some antennas list modulation type alongside power rating?

Looking at HF antennas I've noticed that occasionally I'll see power ratings similar to "200W (SSB)". Why would the modulation matter for an antenna's power output rating, and in the absence of other ...
7
votes
1answer
374 views

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 ...
11
votes
4answers
2k views

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?
6
votes
2answers
371 views

Is it possible for an amateur to transmit ATSC?

Amateur television has long used the NTSC (analog) television standards to transmit video and audio. Several years ago, the digital broadcast television transition made higher-quality television ...
12
votes
3answers
548 views

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 ...
6
votes
2answers
93 views

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 ...
10
votes
3answers
386 views

Does modulation affect propagation?

Does the modulation scheme, whether OOK, SSB, AM, FM, a digital mode, etc, affect the propagation of a signal?
6
votes
1answer
167 views

Does mixed-mode operation qualify as a QSO? [closed]

Working the bands it's quite possible to work in mixed-mode, albeit I doubt whether it is ever done. Call this a thought experiment: Station A operates CW, Station B operates SSB. I find myself ...
3
votes
1answer
139 views

What are the differences in a QSO over A3F as compared to J3E?

All I've ever used is CW, and a some SSB; even then always replying; haven't seen much difference there in the manner of the QSO. But there are other modes which I have not used, and some that are ...
59
votes
16answers
7k views

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?
9
votes
2answers
3k views

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 ...