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TUCoPS :: Radio :: noaa_how.txt

Rcv APT Images From NOAA Satellites








Courtesy Dallas Remote Imaging Group
         Datalink RBBS ============> 214-394-7438

         Dedicated to satellite tracking, decoding of NOAA/Soviet
         meteorological satellite telemetry, and Digital Image
         Processing of satellite pictures.

         Jeff Wallach,      N5ITU, Chairman

         John Williams,            Co-Chairman
         T S  Kelso,               Air Force/NASA liason
         Jim Blocker,       KF5IW, Director Software Development
         Jose Sancho       WB5YFU, Director of Engineering

         All aspects of Amateur Radio covered on Datalink RBBS

 (IF YOU COPY THIS BULLETIN FOR OTHER SYSTEMS, PLEASE BE KIND ENOUGH
  TO LEAVE  THIS BANNER  AS DUE CREDIT TO THE HARD-WORKING FOLKS WHO
  DEVELOPED AND CONTINUALLY UPDATE THIS INFORMATIVE 'HOW-TO'BULLETIN)


                                                               (rev 8)

Tom  Gentry, K5VOU,  has  been  kind  enough  to  help us prepare the
following: 


        HOW TO RECEIVE APT PICTURES FROM THE NOAA SATELLITES
        ----------------------------------------------------

So  you  have  decided you want to receive the NOAA and Russian METEOR
orbiters  and  you  have  a  radio  that  receives  137.500  MHz and a
computer.  So  now what do you do? I hope this short dissertation will
steer you in the correct direction.

To  display a picture from the orbiting birds you need several things.
First  you  need  to  'acquire' the satellite. This means you need the
program to calculate its position at any time and determine if you can
hear  the  signals from the 'bird'. The best place to get this program
is  probably AMSAT-NA an organization dedicated to AMateur SATellites.
They have several very good tracking programs for the IBM and also for
Commodore  and  Apple as well. After you have acquired the program and
have it running on your computer, you then need the Keplerian Elements
for  the  NOAA  satellites.  These  elements  as well as some tracking
programs  are  available from the CELESTIAL RCP/M, run by TS Kelso, at
512-892-4180  (Austin, TX) and from the Weather Fax and Remote Imaging
DATALINK BBS run by Dr. Jeff Wallach, N5ITU as bulletins for some 50 +
sets of satellite  data.   Another bulletin also tells you to what the
printed  numbers  correspond  so  you can enter them into the computer
program.  Use  the  newest  elements  you  can  find  as  the orbiting
satellites are subject to forces which change their orbits. If you use
Keplerian Elements more than 3 or 4 weeks old, your chances of hearing
the bird are reduced.

Once you are tracking the birds you should hear them on your receiver.
They  will  be  on 137.62 (NOAA-9), 137.500 (NOAA-10), 137.850 (Meteor
2-14,2-15),  137.4  (Meteor  2-16), 137.3 (Meteor 2-17). Now comes the
first  thing different about NOAA orbiters. The frequency deviation of
the  FM transmission is about +/-18-20 kHz. This is 4 times the normal
deviation  of  a police call and 1/3 the deviation of the FM broadcast
band   FM   signal.   If   you  receive  the  signal  on  the  regular
communications  width  of  the  scanner the light areas of the picture
will be noisy and the signal will sound distorted and the picture will
basically  be useless. If you use the FM broadcast bandwidth (assuming
your  scanner  will let you), the signal will be weak and there may be
too much background noise to see the picture. 

So  what  now ?   Well there  are two  ways to fix the problem, find a
receiver  with  the  proper I.F. bandwidth filter of 50 kHz, or modify
the  I.F.  of  your scanner to about 50-80 kHz. The simplest mod which
has  been  found to be workable is to remove the narrow communications
I.F.  filter  and  replace it with a 0.01 uFd capacitor. This provides
for  good  Wefax  pictures  from  GOES  and  pretty  fair NOAA orbiter
pictures.  It  can of course result in retuning the radio, voiding the
warranty and making the squelch not work properly. 

The  other  characteristic of the NOAA satellite transmissions is THEY
ARE  WEAK.  To  get  good  pictures  over a large area we have found a
pre-amplifier  to  be  essential. A GaAs-FET type can be obtained from
various  sources at a reasonable price but still about 50-100 dollars.
You  can  also build one for about 25 dollars from plans for a pre-amp
for the 2-meter amateur band and tune it to 137.5 easily.

Lastly   but   importantly,  the  antenna  needs  to  be  of  an  omni
directional,  uniform pattern type such as a turnstile antenna similar
to  those  used  in  the FM broadcast reception business but of course
tuned  to  137.5  MHz.  Mount  the pre-amp at the antenna if possible.
Crooked  coathangers  on  broomsticks have been known to work with the
pre-amps  mounted  on  the broomstick, so it is not difficult to build
the antenna.




Now that you have a nice audio signal from the satellite, what happens
next? The audio tone of 2400 HZ which is the carrier tone that is used
to  carry  the  picture  information (video), must be detected and the
video  data converted from analog to digital and then displayed on the
computer monitor by the software. The hardware and software to do this
is  available  from  several  sources  with more coming along. Several
stand-alone  boxes  are  also  available  that  produce  some  form of
computer  output either in printed form or on the display. In addition
the  people  on the DATALINK BBS may also have some data to share with
you regarding this equipment.

One  of  the  best  sources  for  information is the WEATHER SATELLITE
HANDBOOK available from Dr. Ralph Taggart of Michigan State University
at  602  S. Jefferson, Mason, MI 48854 for $15.00. Taggart also writes
the monthly WEATHERSAT column which appears in '73 Magazine. A must is
THE  JOURNAL  OF  THE  ENVIRONMENTAL  SALELLITE AMATEUR USERS' GROUP -
JESAUG  - which is published quarterly. It is available for $12.00 per
year  from  the  editor,  Greg  Mengell, 2685 Ellenbrook Drive, Rancho
Cordova, CA 95670. Back issues of the 'Journal' are also available. 

At  the  present  the  simplest  software  for  the  IBM  is the Elmer
Schweittek MULTIFAX 3.0 software. A hardware kit is available from A&A
Engineering  which  includes  the  video  dectector  circuit  and  A/D
converter.  Input to the PC is via the game port. If you want to build
your  own,  complete documentation to build an interface circuit on an
IBM  PC  prototyping  board is available from H. Paul Shuch, N6TX, for
$6.00 - FAXBOARD.

The WEPIX(tm) software and hardware should be available from Encomm by
March  1988, and it will produce pictures of 1200 lines by 800 samples
per  line  displayed  at  640  x 350 pixels in 16 shades of gray or 16
colors  using  an  IBM  PC  with 640kB, EGA card and at least one 360k
disk. 



                     'Typical' APT Receiving Station
                     -------------------------------


        [1]   ANTENNA
                 -
        [2]   PRE-AMP
                 -
                 -
                 -
                 -                          [ STAND ALONE UNITS ]
                 -
        [3]   RECEIVER  ----------------->  FAX MACHINE  ---> PAPER
                 -                          WRASSE UNIT  ---> MONITOR
                 -                          YU3UMV UNIT  ---> MONITOR
                 -
                 -
                 -
        [4] - VIDEO DETECTOR   -
            -                  -
            -                  -
        [5] - ANALOG/DIGITAL   -
            -                  -
            -                  -            [ SCAN CONVERTERS ]
            -                  -
        [6] - INTERFACE TO PC  - <=======>  ROBOT 1200
            -                  -            TAGGARTS'S WSH
            -                  -            IMAGEWISE
            -                  -
        [7] -    SOFTWARE      -            ** SECOND DISPLAY **
            -                  -               for weather images
            -                  -
            -                  -
        [8] - GRAPHICS ADAPTOR -
                 -
                 -
                 -
                 -
        [9]   PC DISPLAY / MONITOR

                 Display weather images
                 (or commands for SCAN CONVERTERS)


       [10]   PC PRINTER / DOT MATRIX / LASER


       NOTES:
       ------

              [4] VIDEO DETECTOR, [5] ANALOG/DIGITAL CONVERTER, and
              [6] INTERFACE TO PC may be in seperate hardware units
              or all on one circuit board.

   



Sources:
----------------------------------------------------------------------

NOAA Data / Keplerian Elements:

DATALINK RBBS, N5ITU, Dr. Jeff Wallach, 214-394-7438
 DALLAS REMOTE IMAGING GROUP ELECTRONIC BULLETIN BOARD
 UPDATES ON NOAA BULLETINS, SATELLITE LAUNCHES, FREQUENCIES
 DISPLAY PICTURES FROM NOAA SATS ON YOUR OWN P.C.

CELESTIAL RCP/M, TS KELSO, 512-892-4180

Tracking Software:

AMSAT-NA,  PO  Box  27, Washington, DC 20044, Software Exchange,
 phone 301-589-6062 (voice)
DATALINK BBS, download SATTRAK0.ARC and others       
CELESTIAL RCP/M, TS KELSO, 512-892-4180, SATTRAK0.ARC and others

Receivers:

Vanguard Labs, 196-23 Jamaica, Hollis, NY 11423,
 phone 718-468-2720
Hamtroincs, Inc.,65-D Moul Road, Hilton, NY 14468-9535
 phone 716-392-9430

Crystals:

JAN  Crystals,  2400  Crystal  Dr,  Fort  Myers,  FL 33906-6017,
 phone 1-800-237-3063 or 813-936-2397

Pre-Amps:

THL/Encomm, Inc, 1506 Capital Ave, Plano, TX 75074, phone 214-423-0024
Spectrum   International,Inc.,  Box  1084,  Concord  MA  01742,
 phone 617-263-2145
Vanguard Labs, Hamtronics and GLB for Helical RF Filters for intermod

Antennas:

ARRL Handbook, 1986, turnstile over ground antenna.
ARRL Satellite Experimenter's Handbook by Martin Davidoff, K2UBC

Hardware Interface to PC:

A&A  Engineering,  2521  W. La Palma, Unit K, Anaheim, CA 92801,
 phone 714-952-2114 - both AM dectector and A/D converter, input to PC
 via game port (4-bits) or parallel I/O Interface (8-bits) - kit is
 $50. - assembled and tested unit is $70.
Microcomm,  H. Paul Shuch, N6TX, 14908 Sandy Lane, San Jose, CA 95124,
 phone 408-377-6137 - FAXBOARD - A Weather Facsimile Display Board for
 the  IBM  PC  -  Complete  documentation  to build your own interface
 circuit  on  an  IBM  PC  prototyping  board - video and an 8-bit A/D
 interface - $6.00 

Video Detectors:

RTM  Circuit  Boards,  205  Elm  St.,Van  Horne,  IA 52346-0400,
 video detector  only (the 'Wilson Board') see QST Magazine, Jan '86
QST Magazine, August 1985, Grant Zehr article, page 27, video detector
 circuit

A/D Converter & Parallel I/O Interfaces for the IBM PC:

MetraByte,  440  Myles Standish Blvd., Taunton, MA 02780, Model PIO-12
 board for the IBM PC, phone 617-880-3000
John  Bell  Engineering, Inc, 400 Oxford Way, Beimont, CA 94002,
 phone 415-592-8411

   



Sources:
----------------------------------------------------------------------

Display Software:

Encomm,  Inc.  1506  Capital, Plano, TX 75074, WEPIX(tm) system,
 phone 214-423-0024
Multifax, Elmer Schwittek, 2347 Coach House Lane,Naples, FL 33942, 
 phone 813-434-2268 - Multifax 3.0 for EGA, 2.1 for CGA on the IBM-PC
Clay Abrams Software, 1758 Comstock Lane, San Jose, CA 95124, software
 for the ROBOT 1200 - see QST Magazine, Jan '86
Ralph  Taggart,  602  S. Jefferson, Mason, MI 48854, Weather Satellite
 Handbook  Scan  Converter  -  for  the  Radio  Shack  CoCo3  - see 73
 Magazine, Nov '84 and Dec '84 and Handbook. Ralph Taggart also writes
 the monthly WEATHERSAT column for 73 Magazine. 
Marta Systems, 209 W. Santa Paula St, Santa Paula, CA 93060,
 phone 805-933-1270, 'Live From Space' for the AMIGA PC - $500.
ImageWise Display/Receiver, Circuit Cellar Inc. - Micromint Inc.,
 4  Park Street, Vernon, CT 06066, phone 203-875-2751 - BYTE Magazine,
 May, Jun, Jul, Aug  1987.  JASAUG 88-2 has information to build video
 and  A/D  interface.  Software  is  available  for  $22.00 from Vince
 Coppola, N1VC, 6 Bobbin Road, Terryville, CT 06786 
ASAT: An Apple-based Satellite Imaging System by Grant Zehr, WA9TFB -
 QEX  Magazine,  March  '88  -  has  complete  information to build an
 excellent  unit  using  the  APPLE  with a Redshift Ltd graphics card
 giving 256 * 256 pixels at a full 256 levels of gray. 
AMIGA Imaging Software - Jim Blocker, 2524 Sundance Lane, Dallas, TX 
 75252, contact via the DATALINK BBS. 

Complete Systems - Hardware and Software:

Greg Mengell, 2685 Ellenbrook Drive, Rancho Cordova, CA 95670,
 APT Associates, phone 916-364-1572, Wraase System, FAX recorders, and
 hi-end, commercial units. 
 (Ask for DEPT. J. == Specify referral by Dallas Remote Imaging Group)
YU3UMV  Digital  Storage  and  Scan  Converter  for  Weather Satellite
 Images,  described  in  VHF  Communications Magazine, Winter 4/82 and
 Spring  1/83  -  Modifications  are described in the Satellite Users'
 Group  Journal - JESAUG - available from Greg Mengell. Back issues of
 VHF Communicatons and the YU3UMV printed circuit boards are available
 from  Fred Sharp, TimeKit, P.O. Box 22277, Cleveland, OH 44122, phone
 216-464-3820. 
Loren  Johnson,  P.O.  Box  219,  Cleveland,  MN 56017, system for the
 IBM-PC  -  $750,  phone  507-931-4849
WEATHERTRAC[tm] IBM-PC Based Satellite Image Acquisition and Animation
 System  -  $1885, Fred Bartlett, Softworks, Inc, Allentown, PA, phone
 215-395-4441 or George Isleib, Lehighton, PA, phone 717-386-4032 
TRUfAX  by  CompuMAX  IBM-PC  based  facsimile system - $600, Compumax
 Corporation,  26 West Boylston Street, West Boylston, MA 01583, phone
 617-835-2722 

Bibliography:

NOAA Satellite Predictions, see DATALINK Bulletins
NOAA APT NOTES, see DATALINK Bulletin
NOAA Bibliography, see DATALINK Bulletin
Summary of Soviet Meteorological Satellites, see DATALINK Bulletin
Wrasse Dedicated System, see DATALINK Bulletin
MULTIFAX 2.0, see review on DATALINK BBS - download MULTIFAX.DAT

Review DATALINK RBBS bulletins for more information ====> 214 394-7438

DALLAS REMOTE IMAGING GROUP - DRIG  Voice: 214 394-7325                
P.O. Box 118053
Carrollton, TX 75011-8053



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