The following article was reposted to rec.ham-radio by Richard Crisp (crisp@mips.com) in late 1990; I'm not sure if he's the original author. Questions on this topic should be directed to Usenet group rec.radio.amateur.misc, not sci.space. 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 513-427-0674 (Fairborn,OH) and from the Weather Fax and Remote Imaging DATALINK BBS run by Dr. Jeff Wallach, N5ITU as bulletins for some 80 + 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-11), 137.500 (NOAA-10), 137.850 (Meteor 3-2), 137.4 (Meteor 2-16), 137.3 (Meteor 2-17 and 2-18). 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 can 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, and it is not difficult to build the antenna. Of course 2-meter beams with Az/El tracking will do the job well. 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 $30.00 per year from the editor, Jeff Wallach, PO Box 117088 Carrollton, TX. 75011-7088 Back issues of the JESAUG are also available. At the present the simplest software for the IBM is the Elmer Schweittek MULTIFAX 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 is available from Encomm. 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 - - - - VCR - - - [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 SATELLITES ON YOUR OWN P.C. CELESTIAL RCP/M, TS Kelso, 513-427-0674, NASA Prediction Bulletins | are online and updated several times weekly | Satellite Tracking Software: AMSAT-NA, PO Box 27, Washington, DC 20044, Software Exchange, phone 301-589-6062 (voice), N4HY - QUIKTRAK, W0SL - ORBITS II,III,IV Roy D. Welch, W0SL, 908 Dutch Mill Drive, Manchester, MO 63011, phone 314-391-1127, ORBITS II-EGA, ORBITS III-EGA, ORBITS IV-VGA | DATALINK BBS, download SATTRAKx.ARC, SEESATxx.ARC and others CELESTIAL RCP/M, TS Kelso, 513-427-0674, SATTRAKx.ARC or SEESATxx.ARC | Astronomical Data Service, Rodger Mansfield, 3922 Leisure Lane, Colorado Springs, CO 80917-SPACE BIRDS program and Newsletter, $40. 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 DARTCOMM, Mr. N. Hearn, DARTCOMM Ferndale, Postbridge, Yelverton, | Devon PL20 6SY, Great Britain, UK, phone 011 44 0822 88253 | 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 Ehrler-DuBois Very High Performance LNA for 1500-1750 Mhz, contact | Greg Ehrler or John DuBois via DATALINK | Antennas: ARRL Handbook, 1986, turnstile over ground antenna. ARRL Satellite Experimenter's Handbook by Martin Davidoff, K2UBC Modern Electronics, September 1988, Hank Brandli article, page 82, Receiving Satellite Weather Photos 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 (the 'Wilson Board') see QST Magazine, Jan '86 and Vince Coppola's article in Oct 1988 73 Magazine 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 and Hardware - 'Amateur': 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 3.3 for EGA, 2.x 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 WEATHERSAT column for 73 Magazine. 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. JESAUG 88-2 and Oct 1988 73 Magazine have | information on how to build the video and A/D interface. Ver 2.0 | software supports VGA graphics and 640 samples per line at 64 gray | levels. With VGA the ImageWise Display unit is not required. The | software is available for $29.95 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 - Dallas Remote Imaging Group | PO Box 117088 | Carrollton, TX 75011-7088 | Voice 214 394 7325 | Uses standard Amiga hardware - no special display | Powerful NASA digital enhancement curves built-in | Digital image processing capabilities | Uses A&A Engineering $49 demodulator | Image saved for use by other graphics programs | Full histogram analysis | Full 8 bit data is stored on diskette or hard disk | Unattended operation | Can be setup in 30 minutes | Call for special pricing | IBM-PC Interface Card and Software - Jim MacLean and Paul Atkinson, | 2112 Parsons Avenue, Melbourne, FL 32901, 407-727-3646 - plug in card | for IBM XT or AT, 9600 samples/second at 8 bits, automatic | synchroniztion for NOAA, METEOR and WEFAX, data saved realtime to | hard disk, supports CGA, EGA, and VGA, $300 for hardware and software | Complete Systems - Hardware and Software: Dallas Remote Imaging Group | P.O. Box 117088 | Carrollton, Texas 75011-7088 | 214 394 7325 | Complete Earth-Scan Amiga turnkey system ready to put on air | 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 Jeff Wallach. 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 for EGA - $3495 for VGA, 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 Satellite Meteorology: Satellite Imagery Interpretation for Forcasters - a 3 volume set | published in 1985 for NOAA now available from the National Weather | Association, 4400 Stamp Road, Room 404, Temple Hills, MD 20748, | 301-899-3784, $32 for members, $45 for non-members ( Membership is | $20. ) | Bibliography - Online DATALINK Bulletins: (214 394 7438 -- BBS) NASA Satellite Prediction Bulletins, NASA-PB.xxx How to use NASA 2-Line Keplerian Elements AMSAT Bulletins and Weekly Notes / Orbital Elements NOAA APT NOTES NOAA User Bibliography Summary of Soviet Meteorological Satellites by Grant Zehr How to Build a Weather Satellite Groundstation (This Primer) Wrasse Dedicated System Review GOES VAS Imaging System for the IBM PC, John DuBois W1HDX | LNA for WEFAX-VAS-HRPT-GPS, John Dubois and Greg Ehrler | GOES WEFAX Information Note 89-W1 (3/89) | GOES I-M Converence Summary | Dallas Remote Imaging Group online Image Files | Review DATALINK RBBS bulletins for current information ====> 214 394-7438 DALLAS REMOTE IMAGING GROUP - DRIG Voice: 214 394-7325 Data: 214 394-7438 P.O. Box 117088 Carrollton, TX 75011-7088 ATTENTION: Jeff Wallach, Chairman | New or Changed Items = | | -- Richard Crisp crisp@mips.com MIPS Computer Systems !decwrl!mips!crisp 928 Arques MS 2-02 (408) 524-8177 Sunnyvale, Ca 94086