Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

Questions tagged [digital-modes]

Transmission of digital signals over Amateur Radio, including modes like PSK-31, RTTY, JT-65, JT-9, etc.

Primarily refers to non-voice digital modes, though of course are technically digital modes too.

Non-voice digital modes include: , DPRS, , , , , ,

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What transfer rates are actually achievable using known digital modes?

I've found all sorts of info concerning digital modes, sound samples, spectrum samples, but nobody ever cites what speed a given digital mode can reach. Could anyone tell me more about that, or point me somewhere where I can find this kind of info,…
red-o-alf
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How to calculate UMTS bitrates?

Assuming: Radio frame Subdivided in 15 slots Number of chips: 38.400 Duration: 10 ms; each slots = 666.6 μs and has 2.560 chips Example of channels DPDCH (Dedicated Physical Data Channel) (UL) Spreading factor varies between 4 and 256 Data rates…
beginningperl
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Requirements for 9600 baud

I want to setup a TCP/IP link between my friends house 7km away from me on 70cm. 1200 Baud is a bit slow, and we are looking into something with a faster data rate. I know normal audio does not work for 9600 baud packet. What are the…
Skyler 440
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Checking if the frequency is in use for digital modes

On CW and phone, we are taught to ask if the frequency is in use before calling CQ. Is it correct to say that with digital modes, that is impractical, and you should just listen (over the bandwidth you plan to use) and if you hear nothing, just…
gschro
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Asynchronous vs. Synchronous data transmission speed

Humans are asynchronous receivers, they can pick up words at any time, even if spread out, can combine into a sentence. Data rates are as fast as someone can hear/talk/copy code. All of the fast digital modes are Synchronous, example the HF digital…
Skyler 440
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Digital Protocols, Public Documentation, and Encoded Messages

When is a new digital protocol considered "documented publicly" enough to be used for amateur radio transmissions? Part 97 states the following about prohibited communications: (a) No amateur station shall transmit: ... (4) Music using a phone…
James KE5JOO
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JS8: does a QSO over a relay counts as a valid QSO?

I'm playing with the new JS8 mode. One feature I find particularly interesting is an ability to relay messages using rigs of other OP's. Though I'm not sure whether such QSOs should count as valid ones. Especially if it turns out that the station…
Aleksander Alekseev - R2AUK
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CML FX919B Forward Error Correcting

I would like to decode de-interleaved demodulated 4FSK symbols that were transmitted using the CML FX919B chip. The datasheet only gives the following information: Forward Error Correction In transmit mode, the FX919B uses a Trellis Encoder to…
PC7X
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Transmission speed of modern digi-modes

What are the bit per second ratings and signal-to-noise-ratio ratings of various modern, popular, good performance and well supported digi-modes for HF low power (0.1 watt) long distance (500 to 10000km) communication? My brief understanding is…
EEd
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Which Digital voice mode?

I am looking to get a handheld radio that does digital. Requirements •The most open-source, tweak-able system that I can mess around with. •The lower end price wise •A system that actually gets used, something that I will be able to talk to other…
Skyler 440
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What's the purpose of a soundcard in digital communication?

If I get involved in digital communications do I need to buy a soundcard? If so, why, what does it do?
dcaswell
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Multiple CDMA transmitters with same frequency and code

Theoretical assumption: I have multiple CDMA transmitters operating at same frequency and code placed 5 metres apart. My questions: Does the chances of my receiver receiving the data improve? That is to say does the snr of signal improve at…
user5349
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AFSK signal will not decode

I'm trying to demodulate an AFSK signal. My device uses 1200 baud rate and 1200/600Hz as mark/space. I tried using almost every software for demodulation, but nothing worked. Most recently, I tried QTMM AFSK1200 Decoder. Here is my signal plot and…
EJ Lee
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Which is the most efficient FM digital mode (for data and text)?

At University I studied some stuff about modulation (only two lessons, so my knowledge is very limited) and as far I've understood, the FM signal is most reliable in audio than a AM signal, and it is more power efficient than AM modulated signal. I…
Gigi
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Does anyone have any link to the original papers describing MSK144 and JT4?

I am looking for the original papers describing both MSK144 and JT4 protocols. I can easily find the corresponding papers for some other digital modes such as JT65 or FT8 (mainly at the Princeton Physics website), but no information about these…
user3141592
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