Ham Radio 2000 #2/Ham Radio 2000 - Volume 2.iso/HAMV2/FAX_SSTV/VESTER_M/OPERATWX.TXT

Text File | 1995-10-18 | 11KB | 173 lines

                            OPERATION--Revision B

          The  software programs described here are for use with  the  K3BC
     simple clipper interface described in Sept. 1991 QST.

          The WX and WD programs are designed for minimum keystroke ease of
     operation in practical use. We've tried to build in enough choices  to
     satisfy  different  users  at different times  without  burdening  the
     operator  with too many keystrokes. By setting up default choices  for
     each  question,  you can skip right through by hitting the  ENTER  key
     rapidly.  For  example, I am often late getting tuned up for a  map  I
     really need. By typing WX and hitting ENTER four quick times and  then
     G  to  go,  I can be copying while the mouse-driven,  pull  down  menu
     programs are still fumbling around. On the other hand, when I want  to
     schedule  a  future copy window, and hence have more  time,  the  non-
     default choice automatically gives me a peek at the computer clock  to
     be  sure  it is set properly. This, like other parts of  the  program,
     were added to cover such practical errors.

          The default choices can be easily changed to suit your own  oper-
     ating preferences. Just call up the program at the DOS prompt and  hit
     F5 once. Now LIST (ie, key F1) 0-100, 100-200, etc. to find the  ques-
     tion  you want to change. The line immediately after the  question  is
     where  the default choice is made. After ENTERing the change, put  the
     cursor  in the clear and LIST the line you changed. If it's  OK,  then
     key  F5 to see SAVE instructions. If you just eliminate  the  question
     line  (by putting an apostrophe ahead of the line) the default  choice
     becomes  the permanent choice. In the viewing programs, VWX and  VWXP,
     where  you are likely to want both default choices as is,  the  SYSTEM
     CONFIGURATION  includes a software switch, AU, which will  bypass  the
     questions completely.

          The SYSTEM CONFIGURATION for each program can be viewed by enter-
     ing the program and hitting F5 twice. You can set the COM port,  video
     card,  and interface choice for WX to get started. LT, GT, and SW  may
     require  trimming after you start copying. Since computer time  clocks
     are no longer very precise, some adjustment of the clock  calibration,
     LT (for Line Timing), will likely be necessary. To make this easy,  we
     have  included  "lean right", /, and "lean left",  \,  commands  which
     operate while copying. If the picture leans left, command it to  "lean
     right", /. Since it takes takes awhile to see how much you've  changed
     it,  give the appropiate key a few discrete hits and wait to  see  the
     effect. The new LT value is displayed when you exit the program. (Some
     typical  LT's  found are: 386DX33  tabletop=13400;  286  laptop=13430;
     Toshiba  1900C=13472; Unisys 486SL25=13762). GT and SW may need  trim-
     ming  if  you experience SYNC break-locks while  copying.  The  values
     shown  work  with my 486SL25 notebook. If you  experience  SYNC  break
     locks,  the GT value is decreased 1 unit at a time until there are  no
     break-locks.  If decreasing GT doesn't seem to work, double  the  SYNC
     window, SW, to 60. Slower machines may requirw less GT and larger SW.

          When  copying upper sideband (USB) the radio is tuned  exactly  2
     kc.  below the published frequency. You may want to fine  tune  around
     this  to get the gray shade balance you want. Two different  contrasts
     are  included. The lower contrast (key F8) puts the black at 1500  cps
     and  the white at 2300 cps, which is the published frequency swing.  A
     higher  contrast  (key F9) gives sharper map lines  and  improves  the
     appearance of the SATPIX's. F9 is the default at startup.

          If you miss the SYNC period, you can let the pix be copied out of
     SYNC  and scroll it into a centered position later. Or you can  "Skip"
     the pix to the left about 1/8 of a screen by hitting S. You can usual-
     ly judge how many jumps are needed and store that many S keystrokes. A
     new  class of computer drawn maps are being used for some of the  Navy
     maps.  These are 10 minutes long and have a lot of detail.  They  send
     the  same line 3 times in succession and then send the next  line.  We
     have included an incoming Line-skip function (hit L) which can be used
     to  SYNC our 3 line integration mode (in WX and WD) with  the  "three-
     lines-repeated"  transmission. To see the improvement,  while  copying
     hit  L  and let it run for awhile, then hit L again. You  now  have  3
     samples,  one of which is much sharper. With a little experience,  you
     can quickly tell whether a one line skip or a two line skip will help.
     Particularly look at horizontal lines. If they are one pixel wide, you
     are  there. These maps are generally sent in sets of 3 so if  you  use
     the  37  minute copy time and optimize on the first few lines  of  the
     first map, the SYNC generally carries through the whole set.

          If  you use the NAVY weatherfax, you'll find they  are  sometimes
     late transmitting such key charts as the 36HR and 84HR Blend and also,
     the SATPIX sometimes misses the SYNC period. Actually the SATPIX  come
     over the Weather bureau line precisely on schedule but the Navy  tech-
     nicians sometimes doesn't switch the line on in time---and also leaves
     the  line connected beyond the scheduled time. So the 37  minute  copy
     time  used  without  synchronizing is often useful. Set  it  to  begin
     precisely on the sked time and you'll catch both the maximum amount of
     the scheduled pix plus sometimes you get some interesting  unscheduled
     SATPIX that follow.

          If you use the longer copy time and want to SAVE a pix or a chart
     in  the  middle, just scroll down to place the start  point  into  the
     upper left corner of the screen, choose the SAVE option, and give  the
     estimated number of lines desired (480 lines/screen). You can Print  a
     piece with the same procedure, but you do have to hit any key to  stop
     the printing when it reaches where you want. Otherwise, it will  print
     to the end.

          The  heart  of the actual wefax operation is contained in  a  few
     high speed machine language modules of a coupla' thousand bytes  (.ASM
     in  DIR)  while the interface between these modules and  the  user  is
     handled  through GWBASIC. This makes it easy for individual  users  to
     adapt the programs to their own preferences and also keeps the  amount
     of memory devoted to just loading the program to a minimum. With  this
     memory conservation, we're able to squeeze in a full 37 minutes of pix
     copy into the first 640 K of RAM along with the BASIC interpreter  and
     the  programs.  The  more "modern" QBASIC included in  the  newer  DOS
     versions  is larded up with pull-down menus and other overhead, so  it
     takes  up 194 Kb. of RAM to just load in the interpreter (compared  to
     80 Kb. for GWBASIC). A lot of the same overhead gets loaded into  most
     commercial  wefax programs to give a "modern" look to the user  inter-
     face but, in my opinion, not much added utility. Of course, each of us
     will have a different value judgement on this.

          While WX and WD integrate the data coming in and squeeze the  pix
     into  a  single 640x480 laptop screen, WXP stores all the data  as  it
     comes  in  and displays only a segment of it. As such, it  has  higher
     resolution  for fine details, but without the smoothing you  get  from
     the  integration in WX and WD, it actually looks rougher. It also  has
     manual control of the View and Scroll (hit V after Halting copy). This
     adds  an option of re-starting the copy without having to  go  through
     the  full sequence. That is, hit H to Halt and then G to restart.  All
     the programs have a Shrink (key S) and eXpand (key X) function. WXP  ,
     of  course, uses much more memory and requires you to install  a  RAM-
     DRIVE to accommodate that. Once you install the RAMDRIVE, then use  WD
     since it gives less daily exercise to your hard drive than WX does.

          To squeeze the 37 minutes of data in WX/WD we use the video  card
     memory for both display and temporary memory storage. When you  finish
     copying  a pix, there is a short delay before you can start  scrolling
     (time to dump the screen memory). I hope to shorten this delay in  the
     next  revision.  [Revision A did shorten this and  also  improved  the
     signal processing on incoming data for better picture detail.]

          This  Revision B adds new copying and viewing programs for  those
     of  you  who have machines with SVGA video cards with 512K.  of  video
     memory.  The new capability gives 64 gray shades (or 64 colors)  which
     gives  satellite pix real photographic quality and on the IR  pictures
     gives  temperature resolution adequate to see ocean currents.  It  has
     the high data integration of WX, so S/N is quite good. It was  config-
     ured for VESA cards (all SVGA cards should be either VESA compliant or
     have a TSR driver which makes it VESA compliant). The new programs are
     WXH  and VWXH and they use a suffix of .SVG for the 64  shades  files.
     Both  new programs include the new 64 shades and also the  earlier  16
     shades  capability.  Two new parameters need to be set in  the  SYSTEM
     CONFIGURATION (hit F5 as before) of WXH. The bankshift multiplier, BS,
     gives black spaces between picture strips when too high and the strips
     are  painted with an overlap when too low. Try VWXH on the sample  pix
     LUIS.SVG to set BS. The other parameter, VP, depends on the number  of
     video pages in the video card. Real high speed cards like the ATI have
     two pages. The effect of VP is seen after you copy a picture; when the
     screen  is  downloaded for scrolling, it will only  download  the  top
     strip of the picture if VP is wrong (only choices for VP are 0 and 1).
     We've  tested  this  on Diamond (Cirrus chipset),  Paradise,  and  ATI
     cards. It may not work with all cards, since some older SVGA cards are
     non-standard even with the VESA standard. You may have to contact  the
     manufacturer to get a proper VESA driver.

          Be sure your caps lock is not on. Programs use lower case.

          This software was developed for FREE use by amateur radio  opera-
     tors  and  sailors.  No copies may be made for use  where  a  monetary
     transaction is involved.



                                                  Have fun,
                                                  Ben Vester, K3BC
     September 7,1995