Shut Up and Say Something: Amateur Radio Digital Modes

In a recent article, I lamented my distaste for carrying on the classic amateur radio conversation — calling CQ, having someone from far away or around the block call back, exchange call signs and signal reports and perhaps a few pleasantries. I think the idle chit-chat is a big turn-off to a lot of folks who would otherwise be interested in the World’s Greatest Hobby™, but thankfully there are plenty of ways for the mic-shy to get on the air. So as a public service I’d like to go over some of the many digital modes amateur radio offers as a way to avoid talking while still communicating.

Of Modes and Modulations

Hams speak in terms of modes and modulations when describing their radio transmissions. The difference between the two terms is mostly not important to our discussion, though, and in practice a lot of hams use the terms interchangeably. But for completeness, modulation is a way of impressing information on a radio wave, and a mode is a way of using a modulation to communicate. Modulation schemes include amplitude modulation (AM), frequency modulation (FM), and single sideband modulation (SSB). Modes include continuous wave (CW), analog voice, digital voice, images, and data.

The digital modes I want to discuss are the ones where you can easily sit down at a keyboard and have your message appear magically on another ham’s terminal across the world. I’m not going to cover CW as a data mode here, even though it clearly was the first and is arguably the most successful digital data mode ever. International Morse Code has been going strong for 140 years, and with the many advantages of CW modulation it’s likely to remain a powerful tool for as long as people care to learn their dits and dahs.  Yes, there are applications that will translate keystrokes to Morse and back, but that just feels like cheating.

Equipment

Those of us with long enough memories will recall the early days of the interwebz, when dial-up connections were the only way to get online. The sound of a modem dialing Compuserve or AOL and negotiating a connection was the soundtrack of the pre-Internet days. The modem was modulating the data signals from your computer into audio tones that would fit down the analog phone line, and demodulating the returning audio signals. All ham radio data modes basically boil down to this same process — with the addition of a little outboard equipment, data from your computer is turned into audio tones that are fed to your transmitter, and audio from your receiver is decoded back into data.

In a lot of cases, the extra equipment required to tap into most data modes these days is minimal. There was a time when special converters were needed, but with a powerful DSP built into every computer sound card, pretty much any PC will do. Many ham transceivers now have sound cards built in, too, so sometimes all you need is a USB cable and the right software. FL-Digi is a popular package that supports most of the popular digital modes, provides a waterfall display that lets you easily visualize a huge swath of bands, and even controls your rig, tuning it to the selected frequency and keying the transmitter when needed.

Data Modes

There is a bewildering number of data modes out there, and cruising through the HF bands at night can sound a little spooky. The warbling tones that seem to drift across the bands as the ionosphere does its nightly dance are a little eerie. The audio signature of each data mode is pretty distinctive, and experienced practitioners can pick out the mode just by the sound, or maybe with a little help from its appearance on the waterfall display. Noobs can get help with identifying the modes from any number of websites, or can rely on their software package to autodetect the mode.

Which mode to choose is largely a function of what is going to work best under the given conditions. Unlike modems connected by a telephone line, the physical medium in ham data modes is subject to a lot more potential for interference, both natural and man-made. Signals can be interrupted by crashes of static from electrical storms, two signals can arrive by different paths and suffer phasing problems, or the signal strength can be so low as to be barely above the noise floor. Any useful data mode has to take these vagaries into account, and some do a better job of dealing with one set of conditions than another.

Here’s a run-down of the major data modes you’ll run across and the relative benefits of each:

RTTY

Radioteletype, or “ritty” as hams call it, is the original digital data mode. It dates back almost as far as commercial radio does, with the first RTTY service established between San Francisco and Honolulu in 1932. Then as now, RTTY uses the 5-bit Baudot code to encode each character. The simplest modulation scheme for RTTY is audio frequency-shift keying (ASFK) with a 170Hz difference between the mark and the space bits. This results in a whopping 45-baud connection (you’ll notice that most ham digital modes tend to be on the low side with regard to throughput thanks to the limited bandwidths available at the relatively low frequencies needed to take advantage of the ionospheric skip needed for long-distance contacts.) As slow as it sounds, that’s still about 60 words per minute, which is plenty fast enough to keep up with most typists.

RTTY has been joined by a raft of other data modes, but there are still RTTY aficionados out there plying the airwaves. The lower end of the 20-meter band is a good place to find RTTY operators.

PSK31

One of RTTY’s advantages is that it’s technically easy to implement. But it doesn’t perform particularly well at very weak signal levels. To fix that, [Peter Martinez (G3PLX)] decided to come up with a better RTTY. In 1998, PSK31 was introduced, and it has become quite popular since then.

[Martinez] took a two-pronged approach: first, he developed a new encoding method for alphanumeric characters, called Varicode. Instead of a fixed word length like the Baudot used in RTTY, Varicode’s word-length was more Morse-like, with frequently used letters represented by shorter codes than rarer letters. Then, to modulate the code, [Martinez] leveraged the DSP in a computer’s sound card to shift the phase of an audio signal by 180° to represent a zero in the Varicode, while unshifted audio represented a logical one.

This phase-shift keying (PSK) results in a bit rate of 31 – slower than RTTY, but designed to keep up with the average typist. PSK31 is more efficient than RTTY in terms of bandwidth — only 31Hz wide — and coupled with the fact that receiver and transmitter have to be synchronized and the DSP algorithm lends itself to predicting when to expect the phase transitions that signal data being transmitted, PSK31 excels at pulling data from weak signals.

Packet Modes

The user experience for RTTY and PSK31 is pretty simple — the sending party types a terse, abbreviation-rich message on a keyboard, and the receiving party reads the message on some sort of alphanumeric display. But lest you think that Amateur data modes are just for sending straight text messages like those that were sent by Model 33 teletype terminals back in the day, there are plenty of packet modes for sending more complex messages, including email.

PACTOR is a set of modes that are based on frequency-shift keying (FSK) with a 200Hz shift. Unlike RTTY and PSK31, PACTOR encodes data as 96- or 192-bit packets, which allows the use of the Automatic Repeat Request (ARQ) error control protocol to request packets that fail a CRC to be resent. PACTOR clocks in at around 200 baud.

Unfortunately, PACTOR requires an expensive piece of equipment called a terminal node controller (TNC) between the radio and the computer. To remedy this, the WINMOR protocol was developed. Similar to PACTOR in that it’s a packet mode with error correction, WINMOR does away with the TNC by using an inexpensive USB audio link, or by leveraging the sound card built into many modern transceivers.

Both WINMOR and PACTOR are gateway protocols to the Winlink 2000 network that provides email service via HF radio. Winlink is an extremely diverse hybrid network of HF and VHF radio links into internet-coupled message servers. Emails can be composed with the full-featured RMS Express client that looks and feels pretty much like any other email client. Emails can include attachments and can be sent peer-to-peer or through the network to any other Winlink user.

As useful as the Winlink network is — it has been a huge boon to emergency communications in natural and man-made disasters where local internet service is disrupted — using it is about as exciting as sending an email, because that’s exactly what you’re doing. For my money, digging a one-to-one contact out of the noise with a couple of watts on PSK31 sounds like a lot more fun. I’m glad the Winlink network is there, and it pays to practice with it from time to time, but there are a lot more challenging data modes to explore, at least in my opinion.

I’ve only scratched the surface of the digital modes available to the mic-shy ham. Here’s hoping this gets a few more new people into the hobby, or maybe even gets those licensed but largely inactive hams on the air. After all, we all need more people to not talk to.

60 thoughts on “Shut Up and Say Something: Amateur Radio Digital Modes

  1. Great write up Dan! I agree as a hobby / practical means of communication we need to attract a broader base of communcators. For me, I really enjoy getting on voice and doing SOTA. Hope to catch you all on the air.

    1. Wait for the flying toy ecosystem to stabilize. When the quadrotor guys get a newer battery tech like the sodium glass batteries and runtimes become hours then damn near everyone will be gearing up for long range control which only (legally) comes from having a ham licence.

  2. As a ham that is mic shy on the HF bands due mostly to hearing issues, I find the digital modes a relief. I mostly use WSPR, which is probably the most boring of all the digital ham radio modes. It’s simply a beacon/reporter mode, with no real info exchanged beyond call sign, power level, and location. It is, in my opinion, fun to find out how far away your signal can be heard, and how well your receiving antenna is working. I once had a two-way WSPR contact (I heard him, he heard me) between my home in central New Hampshire and Perth, Australia on the 20 meter band (14 MHz). Both of us were transmitting with a mere 5 watts of output power. That, so far, is my personal distance record, one that will be very hard to beat.

  3. It’s sad to see that poor, dead microphone. It looks like one in my microphone collection.

    I don’t get on the air much, but always have enjoyed contacts. I’m also not much for short, info-only exchanges (except for the occassional answering of contestors), but like a good ragchew.

    I tell people that once an EMP wipes out the cell towers, I’ll be able to chat with cubby, middle-aged, men all over the world with my tube-based transceivers.

  4. What´s the average age of Radio-ams ? What was it 20 years ago ?
    Admit it or not, in those Internet days where everybody is wirelessly communicating with text, voice, pics, videos, this radio-am thingy looks obsolete and not very attractive for the young generations.
    And it´s likely not going to come back soon.

    It should be classified as “retrotechtacular” :D

    1. While it’s true that many a radio amateur is a “silver hair”, that doesn’t mean there are not young people among them. The internet and available wireless technology does present a measure of competition to amateur radio, but they are not mutually exclusive. While you can easily call your friend across town or across the country, you are paying for that service, whereas with amateur radio the “call” is free (ie no charge for usage.)

      The advent and popularity of digital modes is expanding the footprint among the younger and older amateurs, and they are exchanging text, voice, pics and videos, along with expanding the integration of Raspi’s, Arduino’s and such “into the fold.”

      In the event of an outage to your internet/wireless devices (ie weather, disaster, malicious individuals, etc), amateur radio can still be on the air as long as some form of power (A/C, 12v, exercise-bike) is available. During such times, amateur radio is in the mix providing valuable communications to the responders and aid teams.

      “When all else fails, Amateur Radio.”

    2. I got my ham license when I was 23 :’) And the hobby emerged from my love for electronics. I do have to admit that it’s hard to relate to the guys from my club, who are mostly aged 50+…. Now I just kinda do my own thing, and I started digital modes a couple of weeks ago, fun! Still, I know a few young guys who are into amateur radio, it won’t die anytime soon!

    3. The fact that it’s not mainstream is a major perk. Why is there this pervasive attitude over the past 5-10 years that if something is not for everyone it shouldn’t exist? That is not rhetorical…why do so many people think everything has to be mainstream to have any worth, you made the statement, can you even try to explain it?

      So Amateur radio is for a small percentage of the population that takes a true interest in it as a hobby. If that describes 1/100th of a percent, that’s still 30,000 people in the US alone which is plenty for a healthy hobby. You say it’s likely not going to come back soon….it never existed for the masses, there is nothing to come back.

      The internet was a heck of a lot more fun when it was more of a computer hobbiest toy too. Back when Usenet was social media and spamgasims like facebook/twitter/instagram didn’t exist.

        1. Hey now, some of those flamewars lasted for years, and it was a smarter breed of troll back then. It really was very interesting.

          But my point is just that things don’t need to be embraced by the masses to have value and be enjoyable. I’d expect a lot of people on a site like this would agree with that.

      1. Agree. One guy in the old Radio Constructor magazines that I’m reading now was claiming that the essence of “Britishness” is engagement in various weird hobbies. He mentions a guy whose hobby was to record sounds that water makes when going down drains in various places :)

    4. “…this radio-am thingy looks obsolete and not very attractive for the young generations.
      And it´s likely not going to come back soon.”

      … and I thought beards and wallet-chains tattoos and vinyl records were all passé too, yet here we are…

      I for one welcome our future hipster ham-radio enthusiasts, who will lovingly restore and cherish all the retro ham gear that they can get their hands on, and make podcasts about their latest contacts.

    5. Not all of us are past mid-age you know.
      Radio obsolete? Tell me, how many devices do you own that rely on a radio transceiver? I would surmise lots.

      Now, if you were to work on experimenting with building wireless devices, kindly name a single hobby that lets you do experiments in electronics that let you understand how radio works with great detail?

      Saying radio is obsolete “because Internet” is like saying computer programming is obsolete because of the Apple App/Google Play stores.
      Yes, you can download (for free or small fee) that will run on your device and possibly do what you’re after. However, someone has to write those applications.

      By the same example, you can buy a radio module off-the-shelf with a built-in antenna, wire it to your MCU and call it “job done”. Or you can spend some time learning a bit about radio, which might mean you decide an external antenna with a particular design might be better, or you might choose a module at a different frequency, using different modulation, or you might even DIY.

      Some countries (not Australia) have bands of “unlicensed” spectrum, where you can make transmitters for and experiment with without license. Even here, there are bands that are covered under the “Low Interference Potential Devices” class license, where provided your device’s emissions are below the stated power limit and within the bandwidth, they qualify, thus can be used for experimentation.

      However, what if that isn’t enough? Or you want to try something a little different? Unlicensed, you can use that cheap 433MHz FSK module as-is with its minimal 50mW. Get a Standard amateur radio license, and you can slap a suitable band-pass filter and 70cm PA module and get a nice 30W output, and get across town.

      You’ll have the theory needed to understand how to build said PA and filter, match it to an antenna, and get results. And, you’ll have the legal rights to be able to use it.

      No, radio is not obsolete… it is more relevant today than it has ever been.

      1. Glad to hear it. We’ve got a 16 year old Amateur extra in our group. He also knows CW. He started at around 14. I asked him if his grandpa got him into the hobby. I was surprised to find out it was the other way around.

    6. Pretty much a Cliche’ to point out the following these days; but amateur radio was do all things wirelessly that general public does now long before the general public was doing it. Beyond that it’s unreasonable to comer amateur radio to the for profit infrastructure the general public uses. An infrastructure that has money pumped into it on a monthly basis. An infrastructure where two year contract subsidize the low cost of smart phones. Even those who use prepay phone pump in a lot of dollars Imagine what kind of networks amateur radio could build if the hams using them would would pump $1,200 plus into the infrastructure on a monthly basis? About that “radio-am thingy” thing just like hams someone from the general pubis doesn’t does care about the tech use as long as they can communicate. Something that works well shouldn’t classified as obsolete because it decades old tech. Using that metric wireless is ~100 years old the iPhone in my pocket My WISP equipment and the wireless router on my desk are obsolete. Yes it’s difficult to present amateur radio in a way that attracts 1/12 school kids and young adults. Hell it’s almost like work.
      73

  5. Hi
    The “contact” itself is probably the less important and less interesting part of ham radio (more boring ?). Experimenting, building, burning, re-experimenting and re-builiding (without burning this time) is the goal… CQ is clueless. And going D1g1t4l don’t only means “machine generated message” (or keyboard generated). For sure, psk or tty could be fun. But digital voice http://freedv.org/tiki-index.php or digital images https://www.datv-express.com/ are definitely more “geekee”, modern and will definitely teach you more than former digi modes (even if I love the R2D2 sound of Olivia !)
    Marc f6itu

    1. Been reading this thread and so far nobody has mentioned the terribly cool ability of hams to use one of the many satellites in earth orbit, (http://amsat.org) or even if you don’t care to talk to terrestrial hams, theres still the licensed hams onboard the ISS, who often get on the air during their offtime. I’ve been licensed since 1976, and am not into yakking on the radio but I LOVE to build stuff and use it on the air, using one of the many digital modes..

  6. Let me tell you, I’d love to start to work on something a little more “analogy”, and the service hams can provide in a disaster is not to be underestimated, so I’m glad some people really enjoy this, but I’m afraid typing at someone doesn’t sound any more interesting than talking to them to me.

  7. What Dan failed to mention was punch. Digital modes, including CW, are fare more efficient than voice. Meaning, you can communicate a lot farther with less power. Say a 100W SSB transmission from Alaska may not be heard on the East Coast, a 100W PSK will show up on the waterfall just fine.
    Why, SSB has a bandwidth of 2700hz, PSK is 31hz wide, same power in about 1% of the space. Concentration. In reality PSK is rarely worked using 100W, usually 25W is plenty to work the world, even with moderate antennas.
    There are other modes even more efficient. PSK you can usually hear, others, the signal will be so buried in the noise you can’t hear it, but the software can still decode the message.
    These modes also have made it possible for modest stations to work EME (earth – moon – earth AKA moonbounce).

  8. I never got into the phone modes at all — in fact, all my interactions with other hams over voice have left me quite frightened and disgusted.

    Mostly, I’ve been into RTTY, fax, CW, SSTV, and other computer-assisted modes. For the longest time (before Comcast complained I was interfering with their control channels — long story) I ran a variety of 10m propagation beacons.

  9. I’m so glad there are others who just don’t “get” voice mode comms. I’ve got my license, bought a chinese handheld…and that is it. I didn’t care for what I heard over the 2m bands. I’m not sure what I was expecting though. I might try PSK and see if that is interesting.

  10. I think a JT65 / JT9 would also have merited a paragraph.

    It’s more focused on “contacts” than communications, but it is quite neat to have an exchange, than see the results on pskreporter.

    Meaning with 1-5 watts, you get pings from all over the globe from others that have heard you. It’s very narrow band like psk31, so its efficiency is enormous compared to actually talking on a mic.

  11. KD2BYL here, I got interested in ham radio but more for the digital end. I attended a couple of local ham radio club meetings and found they are only more interested in talking. I had asked about digital modes even to the extent of packet radio and I was told packet radio is dead. It should not matter that that it is dead as I wanted to experiment more in the digital end ended up getting brushed off, needless to say I never went back.

    1. “Traditional packet” is dead, that is, the old 1200-baud AFSK (VHF/UHF), 9600 FSK (VHF/UHF) and 300 baud (HF) variants… but there’s more to digital than those modes.

      I personally am considering re-purposing the FDMDV modem used in FreeDV, capable of a raw 1600 bps data throughput, for packet radio communications over SSB. There isn’t much wrong with AX.25 framing used in packet… but the modems are terrible, and slow in this modern age. We can do better, and should.

  12. Is it correct that amateurs are banned from using encryption, but that it is also true that the most perfect data compression is indistinguishable from encryption? For example what if I took all of the huge language corpora that are available and had a routine that converted my message to strings of binary number pairs that were the address and run-lengths of matching phrases in the corpora? The message would be useless to anyone without the corpora but the compression could reduce some long messages with routine content down to 1% of their size. Seeing the reduced message would also be rather humbling as it would be a reminder of how redundant so much of our communications are, hmmm perhaps that is a good thing and would reduce chit-chat?

      1. Except when it is not algorithmic, that is the point, corpora based systems would need you to have a standardised and fixed set of copora (they are a bit like pad based encryption) and that would prevent you from using an adaptive system that had meta-levels for look-ups (codes for code sequences that contained pointers to corpora sub strings) built in real-time from previous data sent between stations. I guess you could have an open and dynamic system if you incorporated the web and each station had a database table that they could update and everyone else could read. But as a purely over-the-air system how could you do it?

        1. Well, you pretty much answered your own question… a private code book system is not compression, it is encryption.

          AMBE for example sails very close to the wind here… it’s compression though, you just have the one supplier for the “code book” and it’s not in a form you yourself can directly read.

          In your example though, you’re replacing pieces of text and words with symbols. It might achieve compression, but technically it is a form of encryption unless the code book is public knowledge.

          In the adaptive example, you’d have to have some way of the other end detecting the new symbols, then querying you for an excerpt of that coropa, which you’d then send over-the-air in reply.

          1. Yeah it is a border case, it is like sending a zip file without the header that contains the dictionary. Zip and similar methods also use a variable length symbol sorted by frequency of occurrence. Presorting corpora like that would be a huge job but it would reduce the data even further. You could just break it down into n-grams then sort them so that the message just has their index value.

            For another method you can just send checksums and let the receiver burn a massive amount of CPU cycles trolling the corpora for the right chunk of text. Some form of rainbow table method could speed that up as you know the total secret and just have to find the substring. This would work with the adaptive method as both parties would keep all messages and so be able to use checksums as references to parts of old messages that consisted of streams of checksums. You just need to tell what level of abstraction each checksum is at. The checksum could be for an entire text then you have start and end markers to indicate the part of that texts you were sending.

            Basically all of this is trading computational power for radio bandwidth, which is a good idea as the later is not growing.

    1. Took me bit to understand what you are saying. In the event I’m correct, here in the US anyway to use your data compression the corpra you use an how you use it has to be made available to the public. What’s with the hate toward “chit-chat” anyway? A good portion of the exchanges on the digital modes can certainly can be characterized as chit-chat.

  13. There are open hardware, stereo USB digital sound card designs, like these based on the T.I. PCM290x family:

    https://github.com/erichVK5/PCM290x-USB-audio-interface
    https://github.com/joesugar/PCM2904_SoundCard_Interface
    http://pavouk.org/hw/usbcodecpcm2902/en_index.html

    These are good if you want to get into digital modes cheaply and need or want more than the mono input provided in some of the cheaper USB sound card devices out there, and for laptops with TRRS connector that can be fussy about input impedances on TRRS audio cables when auto-detecting.

    They are also handy for weather balloon data reception, via a suitable UHF receiver, and also for digital modes like FreeDV.

    Stereo input also allows cheap IQ audio baseband SDRs to be built for the HF bands.

    Don’t forget, 600:600 ohm audio decoupling transformers for eliminating ground loops can be found in old analogue modems and faxes.

  14. Hi …,
    the WSJT modes are working under the noise (EME, VLF, HF VHF).
    The – 18 dB (minus 18) is the limit, like a weak cw signal.
    The highest (- 17 ..up) waveform’s nothing doing – no point about it on HF.
    The audible signal is suitable for cw, rtty … etc

    73

  15. Interesting article and thread! I especially like the references to the young folks who are described as not impressed by Ham Radio when all of their communication happens on their phones, via social media apps, text, and the occasional phone call. Has it occurred to everyone that the cell phone in question uses radio to do all of those things?

  16. “Ham Radio. Yet Another Way To Communicate Without Having To Actually Talk To Anyone”. We’re raising an entire generation with no ability to communicate verbally. Great.

  17. I’m old enough to remember the original purpose the Amateur Radio Service as established.
    To train a pool of talent for the military, and to promote international good will.
    This radio service was never intended to be whole sale for everyone, but to contribute to society.

    The International good will clause was not a mistake, but in order for that to work, we need to make that personal connection.

    This doesn’t diminish any Digital mode, each has their purpose, but there is no emotion in the digital modes, not for me.
    If there is anything wrong with the world today, it’s that peop!e shun personal interaction and hide behind a keyboard.

    To the point a number of people have made about running into “the nasty ham”. You know the ones, they make everything a negative, except their interest. Ignore them, they are nothing but operators.

    This “” hobby “” has so many enriching facets that most anyone from a Preist to the Ruler of a country have found it enriches their lives. I am sure you will contribute positiveky to this fraturnity of brothers that you chose to join when you got your license.

    73’s Ron

  18. I guess I don’t understand. No matter the mode, the exchange of a random contact is going to be a boring or interesting as the parties involved, make it so. I got into Amateur radio for the technical side of this. After I became licensed I drifted toward EMCOMM and public safety/Service. As I acquired transceivers I wasn’t gungho about it I wasn’t shy about making actual contacts. Even with the digital modes two way contacts are the norm eventually.

  19. For what it’s worth, this is my take on the situation:

    https://stuartl.longlandclan.id.au/blog/2017/03/25/emergency-communications-considerations/
    https://stuartl.longlandclan.id.au/blog/2017/03/26/digital-emergency-comms-ideas/

    In short, there are a lot of modes out there for all kinds of intercommunications. We are getting some very good systems out there for intercommunication, capable of pulling signals out of frankly crap conditions. We may not be able to stream 4K high definition video, but a weather map showing an incoming cyclone could be broadcast to you faster than someone can drive a USB stick to you.

    The former is geared at non-HAMs that might have a workable understanding of computers, but not of radio. The latter page is written for the likes of Brisbane Area WICEN Group of whom I am a member. A significant chunk will not apply to US operators as the laws there explicitly forbid encryption, but there are some ideas that I think could be of use even there.

    PACTOR/Winlink is a great concept, but I think we need to look beyond proprietary systems if we want to ensure future interoperability and flexibility.

  20. I find it unsurprising that people who text each other from across the room would find it uncomfortable to actually talk with someone in another part of the world.

    You should try it some time. It’s the way humans are made to operate.

  21. Don’t throw that microphone out yet. If you want to try RTTY or PSK31 or even Morse code, but don’t want another device (USB sound card) to mess with or lugging around a laptop, choose the other USB (upper side band mode), push to talk, and let one of the available smart phone apps encode and decode RTTY or PSK31 or Morse to display and warble out your messages. This may be useful for QRP portable users. There’s no computer, cables, external sound card boxes to handle. It doesn’t work well in noisy restaurant/bar environments.

    Correct me if I’m wrong, but I think pure sine wave tones on sideband are equivalent to CW keying and not treated as modulated CW (MCW) on AM or FM, which is illegal on certain HF bands.

    An external sound card hooked up to your computer frees up the internal sound card so you listen to tunes while the external device deals with the audio from the radio.

  22. I am not mic-shy but was sick and tired of LFI and angry neighbors, so I went to QRP with the new data modes like JT65A and JT9. It gives the hobby a new impuls. Now I can work world wide with 5 Watts (25 watts max) and a single wire antenna.

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