Tech Arsenal 1/Tech Arsenal (Arsenal Computer).ISO/tek-20/amt_apl.zip/QST.DOC

Text File | 1991-01-14 | 24KB | 417 lines

        -----------------------------------------------------------------
        The  following article is a scanned copy from page 53-55  of  the
        November 1990 issue of QST magazine.
        -----------------------------------------------------------------

                     A Beginner's Tour to and Through AMTOR

        If  you've  ever wanted to get on the air with AMTOR  or  APLINK,
        here's a step-by-step course that'll get you started on the right
        foot.

        By Jim Mortensen, N2HOS
        65 Holly Place
        Briarcliff Manor, NY 10510


        There is a rambling road that leads us from one aspect of Amateur
        Radio  to another. Neither maps nor plans are of much value,  but
        somehow,  we just get there. Take AMTOR as an example. I  had  no
        interest  in that mode when I purchased my TNC a couple of  years
        ago.  Far  from it. Instead, I wanted to get out there  with  the
        digital  crowd  on VHF/UHF and master that  exciting  development
        called packet.

        As soon as the TNC was unpacked, I read the first section of  its
        very large manual, hooked up the computer, successfully completed
        the loop-back test and struggled into the night (building a cable
        by soldering five wires into a tiny plug that was never meant  to
        be  touched by human hands the size of mine!). There  were  false
        starts, profane comments and a ruined plug; but finally,  believe
        it or not, my 2-meter transceiver was keyed and I was  CONNECTED!
        My limited knowledge of commands deterred my attempts to  conquer
        the world that night, but I was safely launched into the world of
        tomorrow.   But there was one problem-1 looked at  tomorrow,  and
        didn't like it all that much.  The idea of working like the devil
        to send a message to a friend a few miles away made the telephone
        look  more attractive than ever. The bulletin boards, bless  them
        for all their effort, were difficult to reach during prime  time.
        And when connected, I wasn't quite sure what I wanted to do.  For
        me, packet offered little excitement (DX PacketCluster'-' aside-a
        subsequent  discovery)  and no feeling of involvement  or  accom-
        plishment. Dust began to settle on the TNC.

        Just before I was about to put the TNC up for sale, I decided  to
        try  a little RTTY.  There were some stumbles with the  software,
        but  I  got the hang of it. And am I glad I did! RTTY  became  my
        favorite mode and I soon became acquainted with most of the  "RT-
        FY Regulars" scattered about the globe. In no time I felt like  a
        veteran at the keyboard. DXing was a picnic and I worked  several
        countries that I had never heard on phone.

        Then, I had a contest QSO with Sanjeevi, VU2SJV, and my  troubles
        began.  Along  with my QSL card, I sent a  note  volunteering  my
        services  as a QSL manager. I knew that he was having card  prob-
        lems  because  as QSL manager for VU2GI I was aware that  the  VU
        bureau  wasn't  functioning  and that the  mail  was  subject  to
        "interruption." Sanjeevi was enthusiastic about the idea,  saying
        "Yes,  I'd love to have you as QSL manager ... and, by  the  way,
        I'll send my logs via APLINK... which has regular transfer facil-
        ities...  to VAGE, then to WDRZ, WQWG or VXRA. " On the same  day
        there  was  a  message  on my  answering  machine  via  NTS  from
        WAIURA/9:  "I  have traffic for you from VU2SJV. Please  call  on
        14071.5  mark  frequency. That reads 14073.6 on my rig.  All  the
        best. Frank."

        The  letter and the message might as well have been  in  Chinese.
        Nonetheless, the always-challenging "new mode time" had  arrived.
        That night, on my RTTY sked with Geoff, KB6WSQ, I asked him about
        APLINK.  He hadn't heard of it, but promised to try to find  out.
        He  didn't know much about mark frequencies, either, but  he  did
        switch  us to AMTOR and after a day or two of fumbling about,  we
        had  the  basic QSO routines refined. On the subject  of  APLINK,
        however, we still drew a blank.


        Several  AMTOR QSO's, some with veterans of the  strange-sounding
        mode,  produced  little or nothing. None of them  seemed  to  use
        mailboxes.  I kept calling WAIURA/9 from time to time on  14073.6
        but  could not connect. Magazines and handbooks had  little  hard
        information.

        The  breakthrough  came from both coasts on the same  day.  Geoff
        discovered  that  APLINK stood for  AMTOR-Packet-Link.  The  RTTY
        JOURNAL  provided the clue as to the mark frequency (even  though
        there were two quite different explanations on facing pages, both
        of which proved to be correct). Through a QSO with Peter,  TJIDL,
        I received a file containing most of the active mailbox stations,
        their frequencies, commands and hours of operation. It took about
        30 minutes to download the file (with accuracy guaranteed by  the
        nature of the error-correcting mode). Peter was most generous and
        I will always appreciate his patience. Cameroon had provided  the
        last clue.

        Full of confidence, I started to call away.  But it was too  late
        for the US station that I wanted to reach. The band had  shifted.
        Undeterred, I called G4GSA and connected with little  difficulty.
        The  screen menu was most helpful. I fumbled through the  sign-on
        procedure and then took two very important steps. First, I  down-
        loaded the APLINK command file; then, I sent my first message  to
        VU2SJV. The user-friendly menu tutored me all the way. My message
        was  on  its way to Sanjeevi via VK2AGE and I was on  my  way  to
        becoming an APLINK fan.

        The  next morning, I called WAIURA/9; connected, left  more  mes-
        sages  - both domestic and DX - and picked up messages from  near
        and far. Each day's routine now includes a stop at TG9VT (I  have
        regularly linked with John's box with nothing more than a 54-inch
        antenna on the balcony railing of our Florida apartment, or  with
        the  vertical  atop  our motor home from all over  the  USA)  and
        VK2AGE. Each day there are messages from friends on land and sea.

        Getting Started


        Software/computer/TNC/transceiver  combinations abound and  there
        is  no  way to cover all the possible setups here. The  system  I
        used  at the time this was written consisted of a TS-940S  trans-
        ceiver,  a PK-232 multimode data controller, PC-Pakratt  software
        and  a Radio Shack lap-top (IBM compatible) computer -  a  fairly
        typical installation - at least in terms of the basic elements. I
        have  since  used two other transceivers and  Hal,  Aries-II  and
        Acuterm  software. The command structures vary somewhat  but  are
        equally simple if you focus on the few required commands  covered
        in this article.


        If you have difficulty getting your TNC and transceiver to commu-
        nicate,  or  if  you have software problems,  call  the  manufac-
        turer.  They  are especially helpful in  solving  tough  start-up
        problems.

        From here on out I'll assume you have a functional AMTOR station:
        a  properly  cabled rig; a multimode TNC and  computer  receiving
        AMTOR  signals;  and a correctly configured  and  entered  SELCAL
        identifier  (a  four-letter call with no numbers:  N2HOS  becomes
        NHOS).

        Remember  two  things about AMTOR: Don't use Your  amplifier  and
        don't  send RYRYRYRY! AMTOR is a remarkably effective  and  effi-
        cient mode and is almost always the "last signal on the band."  A
        lot  of power is not required to work stations on the other  side
        of  the  globe, so don't overwhelm a small subband  with  a  huge
        signal.

        Don't tie up the frequency for 10 minutes repeating RYRY for four
        lines,  my call sign six times and yours eight times  before  you
        tell me your name and QTH and then go through multiple IDs as you
        pass the keys back to me. That sort of repetition has no place in
        AMTOR.  Don't  use RYs - period.  This mode  is  a-c-c-u-r-a-t-e.
        Except  under extremely poor conditions, every character is  sent
        and  its correct transmission confirmed before AMTOR moves on  to
        the  next  character group. No other station should  disturb  the
        connection  because  stations in QSO are locked in  a  handshake,
        thus station ID is required at normal intervals only. QRM or  QRN
        can  reduce the effectiveness of an AMTOR link, but  usually  not
        disrupt  it.  And even if the link breaks for  some  reason,  the
        software  will immediately react and start sending the SELCAL  to
        relink.

        Table 1
        Active APLINK  Stations
                                                      Frequency
        Call           SELCAL    SYSOP   Location     (kHz)

        AH6D           AAHD      PAUL    HAWAII       14071.5*
        DLOYB          DLYB      WERNER  GERMANY      14080.0
        DU9BC          DUBC      FRED    PHILIPPINES  14072.0
        G4SCA          GSCA      JOHN    ENGLAND      14070.0*
        HL9TG          HLTG      GARY    KOREA        14073.5
        K7BUC          KBUC      DEL     ARIZONA      14072.5*
        KBlPJ/8        KBPJ      DAVID   OHIO         14070.5*
        NOIA/7         NNIA      BUD     NEVADA       14070.5*
        TG9VT          TGVT      JOHN    GUATEMALA    14074.0*
        V51NH          VVNH      NICO    NAMIBIA      14070.0
        VK2AGE         VAGE      GORDON  AUSTRALIA    14075.0*
        VK2EHO         VEHO      PETER   AUSTRALIA    14070.5
        VK6YM          VKYM      HERVE   AUSTRALIA    14081.0
        WAlURA/9       WURA      FRANK   INDIANA      14071.5*
        WA8DRZ/6       WDRZ      CRAIG   CALIFORNIA   14068.5*
        WB7QWG/9       WOWG      BOB     INDIANA      14071.5*
        ZFLGC          ZFGC      FRANK   CAYMANIS     14070.5*
        ZLLACO         ZACO      NEILL   NEW ZEALAND  14072.5

        *On multiple frequencies/bands.


        Your First QSO

        Okay, let's get on the air. Place your TNC in AMTOR standby mode.
        Tune  around just below the Baudot portion of the  band  (14.070-
        14.080 MHz, for example) and listen for the distinctive, continu-
        ous  sound of the FEC (Forward Error Correction)  call.  Although
        some ops communicate in that mode, it is normally used for  call-
        ing CQ. Here's my CQ as it would appear on your screen (after the
        TNC begins decoding the FEC signal):

             CQ CQ CQ CQ
             CQ CQ CQ CQ
             N2HOS N2HOS
             N2HOS N2HOS
             SELCAL
             NHOS NHOS
             PSE KKK

        Press  F2  (when using PC-Pakratt software) to bring up  the  ARQ
        Selective  Calling menu, type in the SELCAL (NHOS) and hit  ENTER
        (CR/LF).  Your transceiver will now start sending my SELCAL.  The
        QSO  is  now in your hands, so type in my call  sign,  your  call
        sign,  QTH, name and (+?)(Fn/End on the keyboard).  As  you  con-
        nect, the tone will change and your transmitted copy will  appear
        as  highlighted  text in the upper part of the  computer  screen.
        The  menu will indicate that you have a handshake and are  under-
        way.

        I will respond as soon as your (+?) appears on my screen.   While
        reading  my  message to you, immediately start  typing  the  next
        segment of your QSO.  Anything you type will be stored until it's
        your  turn  to  transmit.  Respond to my copy or  pull  down  the
        buffer  that  describes  your rig, or whatever, but  build  up  a
        backlog of coy before the (+?) appears at the end of my transmis-
        sion.  When that sign appears, your rig responds immediately  and
        start  transmitting your copy.  It does so at considerable  speed
        if you have a good connection and a quite band.

        Use  the (+?) character as the "over" signal until you are  ready
        to  break  the link.  Then, if you are the one to  terminate  the
        QSO,   end   your  last  transmission  with  station   ID's   and
        "Control/D."  This breaks the link for the next QSO.

        Remember that you call CQ in FEC and automatically change to ARQ.
        You answer CQ in ARQ, using the Selective Calling menu (F2).  The
        only  commands  you  must know are the  OVER  (+?)  and  DROPLINK
        (Control/D).  Its that easy.  Run a few QSO's to get used to  the
        sounds, commands and peculiarities of the mode, then review  your
        TNC  manuals (you'll be amazed at how much sense they  now  make)
        before moving on to the next round.

        APLINK

        There  are  more than 100 mailbox facilities on  the  HF  digital
        bands, but for now we'll focus only on APLINK stations and  cover
        the  process  from start to finish. (See Table I  for  a  partial
        list-there are about 40 in all.) None of the APLINK stations send
        out a beacon inviting your call (a fortunate development  consid-
        ering the potential for QRM). Thus, the first step is to find the
        correct frequency by calculating the difference between the  mark
        frequency of the APLINK station and the readout on your rig.  The
        Kenwood TS-940S readout, for example, reads the "space"  frequen-
        cy,  which is 170 Hz below the "mark." That means that  the  dial
        must  show  14071.33 kHz to connect with a station  operating  on
        14071.5  kHz.  The  IC-751 would read 14073.6 kHz  for  the  same
        frequency, according to Frank, WAIURA/9.  If you have a different
        rig,  beg,  borrow or steal an explanation about how  it  handles
        mark and space frequencies.

        Tune to the selected frequency (14.074 MHz for the TG9VT mailbox,
        for example) and listen for a while to make sure that there is no
        traffic. Remember, there can be several stations operating on  or
        scanning  that frequency. If it is vacant, press F2 and  type  in
        the  SELCAL  on  the  Selective Calling  menu  and  press  RETURN
        (CR/LF).  Your transmitter will start calling the station and  if
        you are on the "mark," if conditions are right and if the station
        is not engaged with something else on another band or  frequency,
        you  will  connect and the screen will display: DE  TG9VT  PLEASE
        STAND  BY ... (pause) ... IF YOU NEED HELP, TYPE "HELP"  (CR/LF),
        PLEASE LOG IN.  Although you'll want to get the HELP file  later,
        let's forge ahead. Because you are a new, unregistered user,  the
        first  step  is  to  get on the list. So,  type  NEW  N2HOS  NHOS
        (CR/LF).  (Remember, that's the ENTER key.) The screen  will  ask
        you  to  confirm  your  call sign, so  when  prompted,  type  YES
        (CR/LF).1


        Table 22
        Selected APLINK       Commands

        Command or Sequence   Effect

        NEW (CALL) (SELCALL)  REGISTERS A NEW USER

        LOGIN (YOUR CALL)     LOGS IN WHEN REGISTERED

        LH                    LISTS ALL HELP FILES

        LT                    LISTS ALL MESSAGES TO YOU

        LF                    LISTS ALL MESSAGES FROM YOU

        LB                    LISTS ALL BULLETINS

        RN                    READS ALL MESSAGES TO YOU

        P (NUMBER)            READS NUMBERED MESSAGE

        SP (CALL)             SEND MESSAGE TO-END NNNN

        T                     TALK TO SYSOP

        I                     INFO ABOUT THE SYSTEM

        LOGOUT                LOGS YOU OFF


        The  mailbox  now asks GA+?, which prompts you to  do  something.
        Let's  start with reading the bulletins on file. Type LB  (CR/LF)
        to  get a list of numbered subjects like ARRL bulletins,  station
        notes, DX reports and size and date of each bulletin.  (The VK2SG
        RTTY DX report on TG9VT and VK2AGE, available in the wee hours of
        Friday  Zulu is a gem). Before calling up the list, it's  a  good
        idea to turn on your printer because you may want to refer to the
        list  from  time  to time. When the list is  complete,  the  GA+?
        prompt appears.

        Let's  assume  that bulletin number 123 is a juicy  DX  bulletin.
        Type  R 123 (CR/LF).  Leave your printer on if you wish  to  save
        the  information. The screen delivers the information to you  and
        winds up, again, with GA +?. Type LOGOUT (CR/LF) and the  station
        will drop the link.

        If,  for  example, you'd like to send me a  message  via  APLINK,
        compose the message and type it into a buffer or file before  you
        connect.3  Call  the station that I use as a mailbox, log  in  as
        usual  and  when the screen says GA+?, type SP N2HOS  (CR/LF).  A
        message number is assigned and the GA + ? prompt reappears.
        Send the buffer and, to conclude the message, type NNNN on a  new
        line  and (CR/LF). After informing you that the message has  been
        filed the screen will prompt with a GA+?. Type LOGOUT (CR/LF) and
        the station will drop the link.


        Next  time, log in as usual. If the prompt shows (YOUR  CALL)  DE
        TG9VT  QTC 2/2..... GA+?, you know that you have mail,  two  mes-
        sages in this case. Type RN + ? and the mail will be delivered to
        you  automatically.  If  the prompt says  (YOUR  CALL)  DE  TG9vT
        QRU ... GA + ?, there is no mail, so go on to whatever  interests
        you or log out.

        To  send  a message to a DX station, you must know that  he  uses
        AMTOR and that he uses a specific APLINK station. Otherwise,  the
        message will just clutter up the system for 21 days before it  is
        automatically discarded.

        Here's  how  to do it. If you can contact  the  specific  APLINK,
        station directly, the procedure is the same as for domestic  log-
        ins  simply type SP (HIS CALL) (CR/LF). If your message  must  be
        forwarded  to another mailbox, the procedure is somewhat  differ-
        ent. First, compose the message and put it in a buffer or  file.4
        Call  up the APLINK station and sign in as usual.  When  prompted
        with the usual GA+?, type VU2SJV AT VK2AGE (CR/LF). (The word  AT
        is  very  important  and must be used.) The  system  repeats  the
        address  and  asks  for confirmation; type YES  (CR/LF).  A  file
        number  is assigned and the system asks for the message with  the
        usual  GA+?  prompt. Transmit the buffer and  watch  the  message
        being sent.  As it's going out, start a new line and type message
        has  been filed, the station will give you the GA+? prompt.  Sign
        off as usual.

        Delivery  times vary, but messages can arrive at  their  destina-
        tions within 12 to 24 hours, either direct or via an intermediate
        station.  Faster delivery can be assumed if you connect  directly
        to  the  mailbox  used by the addressee. APLINK  is  a  wonderful
        system  and its accuracy normally assures delivery of  the  exact
        copy  you sent. Links can be lost during forwarding,  of  course,
        but the addressee will be so informed.

        There  are other commands and shortcuts that you'll want  to  ex-
        plore as you become more familiar with the system. (And there  is
        the subject of local packet forwarding beyond the APLINK station,
        but  that is the subject of another article.) But these  are  the
        basics  that get you on and off APLINK and allow you to  use  the
        primary  features. Get on the system and use all of  the  facili-
        ties.  Sign on with several stations, get to know the ops,  check
        to see who logs in (I have arranged several interesting DX  skeds
        that way) and read the bulletins.

        There are other types of mailboxes on the air as well,  including
        some  that  I  find very entertaining. Try ST2SA  (STSA)  on  the
        14.078-MHz mark frequency. Sid is in Khartoum and has a marvelous
        menu  and programmed reactions to your information. He will  even
        print  out  a  QSL card on the spot (sorry,  it  doesn't  count).
        Several  others  can be accessed via  Baudot  with  easy-to-learn
        commands.

        Whatever your interest, if you'd like to try the digital modes or
        are  already into RTTY or packet, expand your horizons  and  give
        AMTOR  and APLINK a try. Use this guide to help you explore  this
        unusual mode and exceptional message-forwarding system.

        You'll no doubt join me in thanking Vic Poor, W5SMM, for  writing
        the great software (now past version 4.0) that is the backbone of
        the  system and all of the APLINK operators around the globe  who
        devote so much of their money, time and energy to . the  stations
        required to move our traffic.


        Notes
        1The  next time you call you are entered in the station's  regis-
        ter,  simplifying  the log-in procedure.  When asked to  log  in,
        simply type LOGIN N2HOS (CR/LF), and you are underway.

        2This  condensed  list is extracted from a  typical  APLINK  help
        file.  It is best to download and print the entire help file  for
        your reference.

        3Note  that the first 25 characters form the subject of the  mes-
        sage. Type something like "Hello Jim," hit (CR/LF) and start  the
        message on the second line.

        4The file procedure for PC-Pakratt is awkward but effective. From
        the  main menu, type E. You will be asked to name the file.  Keep
        it  simple.  Type JIM. Complete the message and  hit  ESC.  Enter
        AMTOR  mode and type Control/F3. Select File, 0, type  JIM,  then
        ESC.  The  file is now loaded.  When you want to send  the  file,
        type  ALT/O  (CR/LF)  and the message will appear  in  the  upper
        screen  as it is transmitted. Nine other files can be loaded  and
        sent the same way.