"Lets Get Digital"

Discussion in 'Youth Forum' started by KJ5T, Apr 17, 2006.

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  1. KJ5T

    KJ5T Premium Subscriber QRZ Page

    Another week has gone by and time for another article. Last week I talked about contesting, and I feel that it was a good opening into the world of contesting. However, I really didn’t go in depth on the many different modes that can be used for contesting, so I hope with this article to tie digital modes back into contesting. But, before I begin I would like to take a moment to look at the history of digital modes.

    As we look back to the digital modes, CW (continuous wave) is sometimes referred to as “The original digital mode” which would have been the most simple of all digital modes. As time progressed we became more advanced in what we could do, which led amateurs to eventually have RTTY (Radio Teletype) making use of mechanical teletype machines and an interface known as an MCU. After RTTY came SSTV, which at the time was too costly for many radio amateurs to get involved.

    It wasn’t until 1982 that digital modes made a massive leap when TAPR (Tucson Amateur Packet Radio) introduced the TNC (Terminal Node Controller), which started a revolution; basically radio amateurs had packet mail long before electronic mail over the Internet. This packet set-up consisted of a dumb terminal, a radio, and the TNC. The next addition to the TNC was to make them multimode controllers, which allowed for an easy non-mechanical way to send and receive RTTY. Also added were HF Packet, AMTOR, CW and even SSTV and FAX. Still the multimode controller was not the biggest leap. With modern computers we are now into the sound card era, and amateurs can operate a plethora of modes just using a simple home built interface and their sound card enabled computer. We will discuss these interfaces later in the article.

    So now you know a brief history of the digital modes, and you see that we have come a long way in what can be done, and many enjoy operating on these modes. I find this to be one of the big points of interest in the twenty-first century because of the way we are shifting to a much computerized world. The radio experimenters of 30, 40, and 50 years ago are today the computer experimenters. Many people fail to see the real value of the digital modes, and I hope to open the eyes to those who do not see the value.

    First and foremost, as always in the amateur radio service, the digital modes provide yet another communication median to be used for emergency communications. Imagine sending images directly out of a disaster area; this can be done with both analog SSTV or using Redundant Digital File Transfer (RDTF). Also, while CW has generally gained the highest popularity of a mode to use when the bands are poor and you must get traffic through, PSK31 is also a good mode for emergency communications. While the Signal-to-Noise requirements of PSK31 are not better than those of CW, it is a good second. Though controversial, it is becoming clear that more and more amateurs do not know CW, and because of this we can look towards modes like PSK31 to be a good second best for emergency communications. Also hopefully the use of these digital modes will push amateurs to learn about “the original digital mode” and become active in CW.

    However, though the emergency communications aspect of the digital modes is important, we can’t forget how much fun the digital modes are. As mentioned above, we are far more into computers now then we were 20 years ago. Digital modes provide a median to make contacts using what most people today are comfortable with; the keyboard. While some may compare PSK, RTTY, and Packet to the Internet, these modes still retain that special magic of amateur radio. While you may be interfacing with a computer, there is still an RF link, with few exceptions when it comes to IRLP and Echolink.

    The digital modes have also provided a new means of contesting. Contesters from all around the world participate in various contests throughout the year. Some well known RTTY contests include BARTG, SARTG, WPX RTTY, CQWW RTTY, EAWW RTTY, RTTY Roundup, and the list goes on. There are numerous PSK31 and PSK63 contests as well; in fact some RTTY contests also include PSK.

    Apart from contesting, many enjoy rag chewing on PSK and RTTY. People will spend a great deal of time in rag chew sessions. This ties back heavily into the great hobby. Amateur radio gives people a chance to meet others from all around the world and learn from these people. These digital modes are just another way for this to happen. Modes like Analog SSTV and RDTF also allow for photography nets and such to take place. Though the quality on HF SSTV is not always the finest, local groups here take part in both Analog SSTV and RDTF sharing photographs and improving their digital photography skills.

    So whether you are involved in public safety, contesting, photography, or thousands of other topics, amateur radio digital modes allow you a means to experiment and share information. For the youth it opens up the doors to allow them to use their computer skills with radio, and the digital modes will continue breeding a new era of radio amateurs. I personally hope that these amateurs still take part in the older aspects of amateur radio, but I hope that they also look at the future of the hobby. However, before this can happen, everyone must know what to do to get on the digital modes.

    First off you will need some kind of interface. We mentioned early on both multimode controllers, and simple analog sound card interfaces. We will begin with talking about multimode controllers, and believe me there are many to choose from. Rather then to go into them all, I will go over two Kantronics multimode controllers, and the Rigblaster.

    The first multimode controller that we will look at is the KAM98 by Kantronics, which is one of the more expensive multimode controllers. This one runs at $369.99 from AES. However, it is one of the more sophisticated controllers and includes a lot of options that you won’t find in your everyday soundcard interface it is not the most sophisticated controller. The KAM98 allows amateurs to utilize various different modes, such as GTOR, PACTOR, AMTOR, Packet 300 or 1200 bps, RTTY, NAVTEX/AMTEX, ASCII, WEFAX, EMWIN, HF e-mail, CW, GPS NMEA, Telemetry, Remote Control, Remote Sysop Access, Host Mode, and Kiss.

    The KAM-XL is the most sophisticated multimode controller offered by Kantronics. will run you about $410 from AES, but allows you do to a few more modes than the 98 model, such as Packet (300, 1200 or 9600 bps) GTOR, PACTOR 1, AMTORPSK31, RTTY, NAVTEX/AMTEX, ASCII, WEFAX, EMWIN, Dual Port Mailbox, CW, GPS NMEA-0182, Telemetry, Remote Control, Remote Control Sysop, ACCESS, Host Mode, and KISS. Not only do you get the HF AFSK modulation, but you also get VHF/UFH FSK and GMSK. The KAM-XL also includes a telemetry port.

    The Rigblaster is known by many as the tool for the easiest connection into the digital radio world. With the Rigblaster Nomic, which can be found purchased for around $70 from AES, one receives a trouble free ticket to the digital modes. The various modes include PSK, MFSK16, MT63, SSTV, RTTY, Hellschriber, Contest Voice keying, among others.

    There are also many websites which tell how to build your own sound card interface; however, because of the fact that there are so many different radio and so many of these different projects I won’t take the time to go over this. If one is interested in building their own interface a simple Google of “sound card interface projects” will bring up many pages to look through.

    When the time comes to start operating there are many different programs to download. Some well known programs include MMSSTV, Digitrx, Digipan, MixW, W1SQL, all of these are for Windows, and there are many more out there, most of them are free. For Linux users there is G-PSK31. I could review every one of these pieces of software, but again it would take too much time, and it would be more effective for the user to pick a piece of software that they enjoy using.

    So now you know the fun of the digital modes and how to get involved, the next step is getting involved. I encourage each of you to get involved and come back here to report on your success and failures. If you have already been involved in the digital mode world, I also encourage you to share your existing stories, and your new stories.

    Have fun and 73 my friends!

  2. KC0KBH

    KC0KBH Ham Member QRZ Page

    I'm nearly a full time PSK op. PSK63 is really a blast. I do some voice, but I love PSK. Another good article. [​IMG]
  3. KC9HJX

    KC9HJX Guest

    My favorite digital mode that I use is Apco25, usually on 2m or 70cm.

    If you have DSP8+ it sounds fantastic; crystal clear.

    Sometimes I run DES-XL either with it or without it, but that is encryption I guess, not digital. Still fun stuff. [​IMG]
  4. 2E0GYD

    2E0GYD QRZ Member

    Hi all,
    99% of my hf operation is on psk 31 and its a very good mode at this time of the solar cycle. When I was licenced as M3GYD I was limited to 10 watts power, but on psk 31 ive worked as far as UA9 - asiatic russia, 4X - Israel, and most of Europe using a half sized g5rv aerial in the loft, I would never be able to do that on ssb with 10 watts.

    Ive been operating psk 31 since december 2004 and ive never used an interface, just 2 audio leads from the rig to the computer, anybody new to data is better to get a rigblaster or some sort of isolator as Steve described.

    The software I use is digipan, simply because thats the software I always use and just got used to it, ive worked plenty of stations with old and basic computers like windows 95 with a 400MHz processor and 64Mb RAM, so you dont need an all singing all dancing computer to do datamodes.

    hopefully soon ill be able to do CW as well as psk31 because in my opinion even that beats psk 31 and you can do cw with the most simpliest of rigs.

    I think the reason why you can work better with psk 31 than ssb is because the computer sound card can hear things that the human ear cannot pick up.

    present day i transmit psk31 at 30 watts (although my legal limit is 50 watts) because psk 31 is that good is that 30 watts is the maxinum power by gentlemans agreement because a strong station swamps the waterfall.

    I hope if anybody is thinking of doing psk 31 or any other data mode you will enjoy it as much as I did.

    73 de Rick 2E0GYD
  5. N3CA

    N3CA Ham Member QRZ Page

    I used MultiPSK for PSK31 back when I was K3LNT. I don't think I've made any as N3CA.

    I was addicted to digital modes for about two months, then it just got boring for me. Maybe I'll try PSK31/RTTY again once my antenna system goes back up.
  6. AL2N

    AL2N Ham Member QRZ Page

    PSK is great!

    Low power, far reaching, low bandwidth.

    Farthest contact I made was using PSK31. South Shetland Islands in Antartica on 40w out.
  7. KC0KBH

    KC0KBH Ham Member QRZ Page

    Sometimes, my IC-765 will do 80-90 watts out, depending on band, while keeping a clean signal. I don't know how it does this. I've thought my meters were wrong, but I've asked other ops how it looks, and they've even sent me screenshots, and it looks just fine. Most of the time, I can get 40-50 out, and keep a good signal. I've used Digipan and MixW. I'm waaaay too cheap to buy MixW, so I use Digipan all the time. Cheap soundcards also don't let you run much power on PSK, without getting a crappy signal. I run a Aureal 8820 (Turtle Beach Montego) from an old Dell. Seems to be a top of the line soundcard a few years ago. That's the card I can run 80 watts on. I have 2 soundcards (I once had 3), and a TV tuner in the shack computer.
  8. PE1RDW

    PE1RDW Ham Member QRZ Page

    I think you missed a step in the digital evolution, the ham modem alowed the use of computer generated and decoded tones before the use of soundcards, it was a simple opamp boosting the audio to +-12 volt to be fed into the serial port and a limiter/filter to turn the serial out into a soundgenerator.
    The baycom modem (also known in the usa as baypac from paccom) was a variation on the hamcom modem that uses a 1200 baud modem ic to turn bell tones into bits and the other way around.
    There where also hamcom modems with special audio filters on the input for sstv signals and versions that turned ask fax into fsk fax to be used with weather sats.
  9. KJ5T

    KJ5T Premium Subscriber QRZ Page

    ..and here is a little fun with the title. I am glad several enjoyed the article.

    "I'm doing all the things that I know I'll like, workin' good DX
    I gotta work it just right, you know what I mean
    I worked you on 40, then on 20
    There's nothin' left to talk about, unless it's Horizontal Polarization

    Let's get digital, digital, I wanna get digital, let's get into digital
    Let me hear your modulation, your modulation, let me hear your modulation

    repeat CHORUS

    I've been patient, I've been good, tried to keep my signal on the air
    It's gettin' hard this DX Chasing, you know what I mean
    I'm sure you'll understand my point of view, we know each other digitally
    You gotta know that you're bringin' out the amateur in me

    CHORUS repeats 2x

    Oh, let's get digital, digital, I wanna get digital, let's get into digital
    Let me hear your modulation, your modulation, let me hear your modulation

    Let's get , amateur, I wanna get amateur, let's get into amateur
    Let me hear your modulation, your modulation, let me hear your modulation

    Let me hear your modulation
    Let me hear your modulation"
  10. VE3HBD

    VE3HBD QRZ Member

    I haven't used P25 on ham for a while - not since I sold my Astro Saber a few years ago. But yes, it is definitley a good protocol.

    As with the PS field, the ham community needs to adopt APCO-25 for their digital voice standard. It's open source, and sounds great.

    One of these days I'll get back into P25. I miss that radio more than anything else I've owned (grin)
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