Questions tagged [digital-modes]

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

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9
votes
4answers
15k views

2m or 70cm FM mobile radio for digital mode operation

Are there any 2m and/or 440cm FM mobile radios that have audio inputs for supporting digital modes, like PSK31 or SSTV? I have a Rigblaster that I use with my HF radio so I could get a mike cable and ...
8
votes
2answers
1k views

Moon->Earth 433MHz link achievable digital bandwidth

Let's assume we have the following situation: Transmitter on moon orbit (distance from earth ~400'000km), around 433Mhz. Transmitter power 1W, antenna gain 10dB, circular polarization. Steered to ...
10
votes
2answers
672 views

Can an amateur use cellular technologies with SDR?

Software Defined Radio is opening up many new possibilities for amateur digital modes. One family of technologies that interests me is cellular. 2G GSM voice/sms and 2.5G GPRS data has been proven to ...
7
votes
2answers
778 views

Store-and-forward capable satellites in operation?

The amateur satellite community used to have a small fleet of pacsat satellites (AO-16 and friends), which were capable of store-and-forward message passing: you could upload messages to the LEO ...
6
votes
1answer
4k views

DMR / DSTAR / P25 Software Encode / Decode

The large VHF / UHF digital voice communication modes all require the same AMBE vocoder chip from dvsinc. This surface mount chip can be aquired standalone for a relatively high price or all of the ...
4
votes
3answers
377 views

Is compression “encryption” under FCC regs?

I read this question about digital signatures and FCC prohibitions on "obscuring" messages in amateur transmissions, and it cause me to think of something: the difference between encryption and ...
9
votes
3answers
949 views

Are hashes (such as md5) legal in the US

If I were to implement a remote computer control system using amateur radio, would using hashes (such as md5, sha-*, etc...) for authentication be permissible under the United States rules?
8
votes
2answers
1k views

Do FCC regulations limit digital data rate?

Are there FCC regulations that specifically limit digital data rate on the amateur bands? Are there any recent or proposed changes? If so, what are they specifically?
7
votes
1answer
126 views

Efficient BPSK31 amplification

I'm looking at making a portable system that can transmit BPSK31. I have a limited power budget, so I'm looking at trying to make my final power amplifier as efficient as possible. From my ...
6
votes
1answer
1k views

Confusion about radio-computer interfaces: TNC, CAT, TRRS, Wolphi Link, …?

This is probably a very simple and stupid question, but I'm getting more confused over time. Perhaps it is a matter of terminology, but a unified resource differentiating and explaining the different ...
5
votes
3answers
773 views

Unidentified signals on FT8 frequencies

When I work in FT8 mode I often see signals like these: I couldn't identify these signals using SigiWiki nor managed I to decode them using WSJT-X. Though these signals seem to use 15 second frames. ...
4
votes
2answers
658 views

What is the minimum equipment necessary to get on the air with FT8?

To the extent that FT8 is a way to bring people into the hobby or re-ignite passion among those who haven't been on the air in a while, what's the easiest way to get someone on the air with this new ...
3
votes
4answers
478 views

Is there an FT8 or other weak-signal digital mode specification available?

Is there a complete and programming language independent specification available for the FT8 digital mode? Detailed enough to implement both transmit and receive SDR software from scratch in two ...
3
votes
1answer
90 views

How to fix SignaLink non-linearity problem?

I decided to check the linearity of my Yaesu FT-891 signal using an RF sampler and an oscilloscope. To generate two-tone (1550 Hz, 2150 Hz) signal I used Audacity. To connect the transceiver to the PC ...
2
votes
2answers
107 views

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 ...
2
votes
1answer
97 views

How to scan while avoiding digital/noise frequencies?

Is there an established way of scanning frequencies, while avoiding listening to digital signals or static? For example, is there a scanner on the market which will allow you to blacklist a specific ...
2
votes
1answer
337 views

Can HDSDR perform the work of Direwolf?

I have a setup in which Direwolf is used in conjunction with a Baofeng radio to basically send data (AFSK). My app connects to the TCP server provided by Direwolf, send him some data which then is ...
2
votes
2answers
383 views

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 ...
-1
votes
1answer
149 views

Transmit data over HF signal 10,000km away [closed]

I would like to transmit trinary data (-1,0,+1) on 20-30m wave to be received 10,000km away. From Europe to US. My first thought was this: https://www.researchgate.net/figure/Burst-modulation-mode-f-...
-2
votes
2answers
103 views

Can I transmit bit data over FM signal on 30m wave 10,000km away? [closed]

I am trying to understand if it's feasible to transmit -1,0,+1 data using FM on 20-30m wavelength to be received 10,000km away. From Europe to US. Ultimately I would like to create a solution which is ...