Skip to main content

Questions tagged [digital-modes]

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

Filter by
Sorted by
Tagged with
0 votes
0 answers
19 views

rsid seems hard coded to be disabled when in PSK31 or RTTY mode. Only works for other modes

So I asked ARRL about the RSID being sent before they make a bulletin transmission, which they said was on but it was not being sent that I could see before the transmission. The RTTY mode just starts ...
2 votes
1 answer
125 views

Is there a malware problem with latest JT Alert?

I just went to update JTAlert 2.62.1 and when it finished downloading the built-in Windows scanner flagged it as malware, said there was a "severe" vulnerability in one of the DLLs in it, ...
1 vote
1 answer
302 views

FLDigi Crashes When Trying to Load RigCAT Description File

I am trying to setup FLDigi with my ICOM-7300 via the USB connection so I can start using digital modes. Everytime I try to follow the instructions here, it doesn't work. Specifically, everytime I try ...
3 votes
1 answer
2k views

How to send DMR SMS using MMDVM modem or hackrf?

I have a baofeng DMR radio with SMS feature, and since there is not much DMR radio owners in my area I want to do something myself. The easiest thing I can do I thought is to send myself some SMS as ...
5 votes
1 answer
135 views

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 ...
3 votes
1 answer
88 views

Can I use a generic FM 2m radio for meteor scatter or other digi modes?

Firstly, I know it’s possible, but is there any actual activity for 2m MS. I want to get into Meteor scatter but i am wondering if i can use my 2m FM transmitter with a TNC and a yagi for meteor ...
3 votes
0 answers
108 views

APRS-IS filter by message sender

I'm using KD0NKS' JS-based APRS-IS demo to query APRS-IS servers directly. I'm trying to only receive messages sent from my callsign using server-side filters. I've tried using a budlist filter (b/), ...
2 votes
2 answers
869 views

What devices are able to decode the EAS SAME headers, attention signal, and encoded marker?

When I was watching television, especially when I was younger, I sometimes heard a loud noise, followed by either a test message, or a genuine emergency broadcasts, like an Amber alert. The first ...
4 votes
4 answers
14k views

How can I decode an AFSK 1200 baud audio clip? (ISS)

I'm a new ham. The past few days, I've had a few nearby passes of the International Space Station. As it was going overhead, I managed to record what I believe to be 1200 baud AFSK transmissions from ...
1 vote
2 answers
1k views

GFSK Demodulationsoftware

I need to demodulate and decode a signal.It is transmitted from a satellite using GFSK. The packets are based on AX.25. Could you recommend any out-of-the-box HAM software packages that could do ...
2 votes
3 answers
676 views

FT-450D not transmitting with microphone

I've been using FT8 on my Yaesu FT-450D for quite some time. I decided to try to talk on phone frequencies and discovered neither one of my mics will transmit. My mics are the original hand mic and a ...
6 votes
7 answers
9k views

Are there any commonly used digital modes that work with an FM transceiver?

Like many new hams, I have just one radio: an inexpensive 2m/70cm FM transceiver. It doesn't do SSB and it doesn't have a digital input. If I wire up a connection between the radio and my computer's ...
0 votes
1 answer
100 views

Transfer digital data over ham radio frequencies using QPSK modulation SSB-QPSK transmitter

If I use QPSK modulator/demodulator is it possible to transfer digital data over ham radio frequencies. SSB-QPSK transmitter
1 vote
0 answers
240 views

Is APRS the tracking protocol for the BTech GMRS PRO or the Vero 75 Ham version

Looking for confirmation if the Btech GMRS Pro and the Vero 75 are using APRS as the tracking protocol for their radio's. We're working on an EmComm/ EOC integration project and were looking to see ...
1 vote
2 answers
244 views

FSK: Selecting center frequencies and Carson's Rule

I'm implementing 2FSK and 4FSK modulation schemes for an experimental system. I'm using GNURadio, although that shouldn't affect the question. I'm trying to figure out how the center frequency should ...
0 votes
2 answers
64 views

Why does Tone Spacing decrease with increasing T/R Periods in WSJT-X modes?

In various weak signal modes of WSJT-X, the Tone Spacing decreases with increasing T/R Periods. For instance for FST4 / FST4W (as decribed on page 1 of the Quick-Start Guide) we see: T/R period (s) ...
4 votes
1 answer
177 views

What value goes in the AX.25 PID field if the Layer 3 protocol is not defined in the standard?

I am working on space-ground networking for a Cube Satellite, and one of our candidate Layer 2 protocols is AX.25. We haven't settled on a physical layer, but it's likely to be some form of quadrature-...
3 votes
2 answers
281 views

What exactly are Gold sequences and how are they used?

I recently became familiar with the FX.25 protocol extension for AX.25. Within the protocol is what they call a "correlation tag", which is a Gold sequence or Gold code. I've heard that Gold ...
0 votes
2 answers
459 views

Cannot establish AX.25 connection to RMS gateway

I'm trying to establish an AX.25 connection to a nearby RMS gateway (should be within a mile) using a Baofeng BF-F8+ on 2 meters. I'm trying to establish a connection with either RMS Express and UZ7HO ...
1 vote
1 answer
128 views

How do you open ax.25 ports?

I'm trying to follow this tutorial I almost got to the end, about 9:15 was where I got stuck. Right about there, the speaker is about to wrap up- but I get a couple error messages. ...
10 votes
2 answers
3k views

Am I really receiving FT8 signals from 12,000 km away on 144 MHz?

I have been using an Ettus B200 SDR to receive FT8 transmissions in the 2-meter band (144.174 MHz) using the WSJT-X software. Signals are received using a telescopic antenna inside on a window ledge ...
7 votes
3 answers
413 views

Has any computer been hacked over amateur radio digital modes?

We don't normally worry about security in ham radio, because we can't encrypt our transmissions anyway in the vast majority of cases. Some niche protocols support authentication of messages, but that'...
4 votes
2 answers
193 views

Are there any modes that use pseudo-random noise codes to "amplify" signals?

GPS for example uses them to allow receivers to decode extremely weak signals far below the noise floor. From https://blank005.tripod.com/gps/psedo_random.html : If we tuned our receivers to the GPS ...
2 votes
3 answers
617 views

Receiving BFSK on Kenwood TS2000 transceiver

I have a digital data signal with frequency in the 434-438 MHz band. The data is BFSK modulated with frequency deviation of 9.6 khz, baud rate of 1200 bps. The bandwidth is 25 Khz. Is there a way I ...
2 votes
1 answer
158 views

Getting a PTT Signal for Digital Radio Kit; Right Channel PTT in JS8Call

I want to buy this 5 W transceiver kit from QRP Guys, link. My plan is to use it with JS8Call on an ARM64 Chromebook I have or even my smart phone with AndFlmsg (FSK modes). It's clear that the radio ...
3 votes
1 answer
94 views

Is there a list of public datacasts?

I know several datacasts which are free to almost free to receive. Like there is the outer(other-)net, which can be received using a lora module - it contains a subset of APRS messages and weather ...
4 votes
1 answer
190 views

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 ...
1 vote
3 answers
227 views

Using two radios for a faster data rate

The maximum data rate on UHF is 56kbaud. This is well over most "high-speed" 9600 baud transmissions. Is it possible to use two receivers at one site, and two transmitters (vice versa when ...
3 votes
2 answers
254 views

Can someone without privileges on a band operate FT8 on it using the callsign of a ham who does and is present?

I have an Extra license. Is it legal for my dad (who has a Technician license) or my mom (who is not licensed) to operate FT8 on 20 meters using my call sign, if I am physically present at the control ...
1 vote
1 answer
287 views

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 ...
4 votes
2 answers
305 views

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 ...
2 votes
1 answer
211 views

Automatic identification system (AIS) on aprs.fi - Long Rx -> Tx distances

I've been looking into some of the info available on aprs.fi, which also makes available AIS data, but most of the reports I see have such large Rx->Tx distances that I'm not clear on how things ...
4 votes
2 answers
372 views

How do you log (or not) "busted" FT8 QSOs?

When do you decide (when NOT in a contest) to log an "incomplete" FT8 QSO? For example, something like this: ...
1 vote
0 answers
244 views

Improving Vara HF speeds

I'm using Winlink with a laptop hooked up to an IC-7300. The registered version of Vara theoretically supports speeds up to 8,500 bps, but I'm seeing speeds more like 700 bpm. Is there anything I can ...
9 votes
4 answers
18k 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 ...
7 votes
3 answers
1k 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 ...
3 votes
2 answers
6k views

WSJT-X V2: How to identify stations already logged?

In V1.9 of WSJT-X, there was a feature that allowed one to change the color of stations already logged. This was necessary in knowing whether or not to respond to a given CQ. In version 2, I am ...
3 votes
1 answer
406 views

Open source RS41 decoder

I would like to decode the signal from a RS41 radiosonde (from a weather balloon), which are suggested open-source software to do that? I tried RS but after compiling the code and executing ...
1 vote
2 answers
2k views

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?
1 vote
0 answers
67 views

HobbyPCB IQ32 SDR Data modes cable?

has anyone DIY datamodes cable for HobbyPCB IQ32 SDR ? Im thinking of using SPKR/MIC/PTT port and expose it either towards external USB soundcard (or USB soundcard stick), or directly to laptop USB. ...
5 votes
3 answers
1k 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. ...
2 votes
2 answers
1k views

Receiving audio output from IC-9100 through USB port

Can someone please give me a clue here? I'm having problems receiving data from the IC 9100 radio. I want to receive ax25 packets using FSK G3RUH modulation with an IC-9100 radio. It is configured ...
1 vote
1 answer
48 views

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 ...
3 votes
1 answer
357 views

What is the format of Yaesu FT3D's QSOPCTDIR.dat and QSOPCTFAT.dat files?

The Yaesu FT3D can send photos, but only if taken with the optional external mic that has a camera. I want to be able to send photos that come from elsewhere, by putting them on the SD card. But it ...
6 votes
2 answers
109 views

How does a digital demodulator know which level it is reading?

I have recently started getting into wireless digital communications and I read about QAM modulation. But I am a little confused as to how the receiving demodulator would know which symbol it is ...
2 votes
0 answers
169 views

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 ...
2 votes
2 answers
978 views

Why is a separate repeater required for digital modes? Why can't an analog repeater be used for digital modes?

Regardless of the mode: digital or analog, the radios always transmit sinusoidal EM waves. So wouldn't a regular analog repeater be able to rebroadcast that EM signal regardless of its encoding?
0 votes
2 answers
82 views

What is "allied mode" with regards to PSK31?

Wikipedia says: Colloquial usage of the term 'PSK31' in amateur radio usually implies the use of the most commonly used variant of PSK31: binary phase shift keying (BPSK). BPSK uses no error control, ...
3 votes
4 answers
628 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 ...
-2 votes
2 answers
124 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 ...