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, , , , , ,

160 questions
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Is there a disadvantage to using a cheap HT for APRS?

Looking to build a cheap (not even inexpensive, just dirt cheap) APRS beacon transmitter. Right now you can get a dual band handheld transceiver with rechargeable battery, antenna, etc for under $31 [USD], for instance. I can't find a cheaper…
Adam Davis
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Is Morse code a digital, binary mode?

At first glance Morse code looks like a digital mode - there are dits and dahs, two values which contain the information of the transmission. Alternatively, at any point in time there either is a signal, or there isn't. Morse code follows the…
DK2AX
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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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What is generally considered "too much" power for JT-65 on HF?

Recently, I have begun experimenting with JT-65A, mostly on 20 meters. I usually run about 5 watts with that mode, since I know that JT-65 is a weak-signal mode. Is that still too much power? What is generally considered excessive power on JT-65?
krzysz00 KF5SOQ
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How do I discover APRS coverage?

I'm considering adding simple APRS transmitters to my vehicles. I'd rather just put one in and forget about it, but I understand there are areas of the US where a stronger transmitter would be required to successfully send an APRS update…
Adam Davis
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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 work with OpenBTS on a USRP SDR using licensed…
JC Hulce
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How to operate on HF if an AM transmitter is only 540 feet away?

I'm a General Class Licensee, and due to pulmonary disease I cannot operate voice. I am also about 540 feet from a 24/7 1 kW AM station. The signal is so pronounced that most audio devices in the house pick up the station. Every shortwave receiver…
Gordon C
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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?
W8AWT
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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,…
Redoman
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Getting Started with Digital Modes on VHF on Linux

I am interested in learning about digital modes using 2m and Linux. I have a couple of older 2m rigs (HTX-212 and an old Yaesu) with no additional hardware, like a TNC. What current resources exist for hardware setup and software configuration for…
Rob Gibson
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What is a fixed digital message forwarding system?

What is a fixed digital message forwarding system? I noticed this on the lower end of the 222MHz allocation in the US but it's not explained on the band chart:
Adam Davis
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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 with approximately 1 m of cable. I have made no…
David
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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?
Phil Frost - W8II
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How can I do direct digital synthesis of a 630m WSPR signal?

I want to do direct digital synthesis of a 630m band WSPR signal. Specifically I'd like to use an Atmega 328 chip running at 20 MHz to produce such a signal. I will use standard phase accumulator algorithm which I believe I can get to run in less…
Eric Urban
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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 point to earth. Receiver is on Earth. Antenna is…
BarsMonster - R2AYN
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