Published: 20. 9. 2012   Category: History of SSTV


Note: These original articles describe famous FSTV/SSTV converter Robot Model 1200C. During the 80s, the must have equipment for SSTV operations which can be used today too. The 1200C is sometimes available on EBay with prices about $100, but always check if it contains EPROM and oscillator upgrade[2]. Without this upgrade only Robot modes are available, with the upgrade also free-run modes like Martin or Scottie can be used.

  • [1] Dewitt, H. William, W2DD: The Robot Research Inc. Model 1200C Color Slow Scan Converter. CQ, Jun 1988.
  • [2] Goodman, Dick WA3USG: SSTV with the Robot 1200C Scan Converter and the Martin Emmerson EPROM Version 4.0. 73 Amateur Radio Today, Jul. 1991

The Robot Research Inc. Model 1200C Color Slow Scan Converter

BY WILLIAM H. DEWITT, W2DD

In the days when we ran a regular SSTV column. Bill DeWitt, W2DD, was its editor for several years Bill was one of the original devotees of SSTV and that slow moving green picture. Recently. Bill's interest in SSTV rekindled and he, like you, has a whole new world of high-tech gear at his disposal —K2EEK

Slow scan television is a still picture transmission system invented by an amateur named Copthorne MacDonald about 30 years ago. On a worldwide basis there are probably about 30,000 amateurs using SSTV at present By gentlemen's agreement SSTV is used principally on 3845, 7171, 14230, 21340, and 28680 kHz, but a whole range of frequencies can be used in accordance with license classification.


Obr.: Front view of the Robot Research 1200C color scan converter.

Slow scan television has come a long way since its invention by {the then college senior) Copthorne MacDonald. in MacDonald's system, image brightness information is converted into audio tones ranging from 1500 Hz (black) to 2300 Hz (white) to create a 128-line picture in 8 seconds. This brightness to audio tone relationship is stifl universally used, An SSTV signal has a characteristically strong warbling sound as you tune across it.

In the early life of SSTV, pictures were displayed on a long-persistence screen CRT. There was a disturbing disappearance of the top part of the picture as the 8 second scan ended at the bottom. However, the system did work and it provided the basis for continuing effort to improve it,


Obr.: By combining pages 1 and 2, one 240-line full-color picture can be stored.

Obr.: Another variation easily accomplished is "quad" operation, where up to four reduced-size pictures can be displayed.

SSTV In The Digital Age

With the advent of digitized data handling and IC storage systems the just-mentioned transient nature of SSTV pictures was eliminated, and over a period of time a number of color SSTV systems came into use The Robot Research Inc. Model 1200C Color Scan Converter introduced a few years ago now dominates color SSTV operation in the U.S.A. and a large part of the rest of the world. Without a doubt it has also been a prime factor in the rebirth of interest in SSTV. More SSTV stations are coming on the air every week and intercontinental exchanges of color pictures have become a non-event!

Against this background, now seems like a good time to have a look at the picture quality and operating features of the Robot Model 1200C.


Obr.: VK3LM, John, left with VK4ZG, George, or Brisbane.

First Things First

The Model 1200C I tested was well packaged and arrived in perfect condition with basic cables and instruction manual. It's a compact, low-profile piece of gear only 11.25" W × 4.0" H × 12.5" D. Power consumption is an underwhelming 10 watts.

The notebook-form instruction manual supplied is excellent. It gives specific operating instructions and tells how to make a demonstration tape that helps the user get started with the 12QQC. It also includes a wealth of information regarding computer controlled operation, hard copy printout, the use of an RGB monitor, necessary diagrams, and sample programs in Basic. My congratulations to Robot for producing a manual that can be understood by someone other than the inventor!

Now let's get down to the nitty-gritty and review the features of this little gray box that helps amateurs send pictures all over the world.

A General Description

The Robot Model 1200C is a microprocessor-based high-resolution color video scan converter and image processor. Its design technology is based on an 8031 microprocessor system including 16K bytes of ROM and 2K bytes of RAM image display is supported by 1,105,920 bits of RAM. High-quality full-color images can be transmitted or received over any voice-grade communications link in as few as 12 seconds per frame. Since brightness and cotor data are multiplexed in transmission, images appear in full cotor as they are created on the monitor screen.


Obr.: Treasury Building and Town Hall, Perth, Western Australia

When combined with a suitable host computer, the 1200C will support sophisticated image processing as well as error-free digital image storage. Pictures can be held in memory for continued viewing and/or stored for future use on an ordinary cassette tape.

Many modifications have been devised and applied to the 1200C This review deals only with the Model 1200C Color Scan Converter as sold by Robot Research Inc.

Some Comments On Picture Quality

If you have any memories of "old-time SSTV," throw them away! Under good conditions overall picture quality approaches that of U.S broadcast television. For a given receiving condition, picture quality varies in accordance with frame time. Color reproduction is excellent.

A Few Comments About The 1200C Controls

The 1200C uses state-of-the-art concepts in control-panel design. Twenty-seven light touch switches with LED indicators are used to control all functions except camera brightness and AC input. The light touch switches are physically grouped according to Junction. A logical layout of the Memory, Speed, Display, and other controls makes it easy for the operator to choose or change functions quickly, Red LEDs let you know what functions are enabled.

Principal Features and How They're Used

  1. Five signal inputs are possible on the 1200C. They include: standard color bars, received SSTV audio, taped SSTV, frame grabbed camera SSTV, and "other" for a source of your choice. Similar outputs are available for transmission.
  2. Compatibility with other systems. The 1200C can send and receive 8 second B/W pictures, and its 12 second color pictures can be received as B/W on scan converters having that frame speed. These built-in features make the 1200C compatible with the thousands of stations still operating in solely the B/W mode.
  3. As delivered, the 1200C is not compatible with a line-sequential system widely used in Europe.

  4. Color and B/W Camera Capabfe. Almost any color camera will work with the 1200C. You can also make a composite color picture using a black-and-white camera with color filters to sequentially record (and then combine) red, green, and blue filtered images of still subjects.
  5. Multiple Speeds. Four frame speeds (each) are provided for color and B/W operation. This feature lets you choose the speed that works best with the prevailing conditions.
  6. A Two-Page Memory. There are six independent image memories, three to a page. These memories may be loaded, transmitted, or processed in any order desired. They can be combined to transmit or receive medium- or high-resolution full-color images.
  7. Two 120-line pictures can be stored at the same time (one on each page).

    Combining pages 1 and 2, one 240-line full-color picture can be stored; see fig. 1. Combining pages 1 and 2 also permits "QUAD" operation in which up to four (reduced size) pictures (the same or all different) can be displayed in the four quadrants of the monitor screen; see fig. 2. A dream of the sixties comes true!

  8. Transmit Cursor. A full screen width cursor indicates the image line being transmitted. This is a very useful feature when transmitting pictures or taping a series of pictures.
  9. A total of 262,144 possible Color Combinations. Eighteen bits of digital information define each picture element, making available a practically unlimited palette of colors. The color reproduction is truly excellent.
  10. Color Bars. Standardized color bars can be enabled for set up and testing or for direct transmission. Great for adjusting your color monitor.
  11. Fully Automatic Receive Operation. At the user's option the 1200C will perform ail SSTV receive functions automatically when receiving color SSTV signals originating with another 1200C. This is high-tech at work.
  12. Automatic Fine Tuning. ROBOT developed software detects mistuning over a 300 Hz range and compensates automatically, assuring accurate color reproduction. This feature is especially helpful to a distinguished few operators who consistently miss-tune SSB voices.
  13. Computer Interface. When interfaced with a suitable host computer, the 1200C becomes a sophisticated image processor limited only by the controlling software. Great graphics from W5ZR and N6GEA demonstrate this daily.
  14. Printer Interface The 1200C can easily be interfaced with any Epson Series 80 printer with graphics capability to produce black-and-white hardcopy output. ATranstar 315 Color graphics printer is necessary for color reproduction.
  15. Model 1200C units operating on 60 cycle current are configured for NTSC composite color video; 50 cycle for PAL composite color video.

With its price tag of $1295.00, the 1200C is not an inexpensive piece of equipment. It's also a piece of equipment with a state-of-the-art design that permits creative use of the unit by itseif or in combination with computers and other graphics sources. It has a reputation for good, stable operation.

If you enjoy the excitement and pleasure of viewing good-quality pictures of faraway amateurs, their homes, families, cars, places of interest, and countless other subjects, then this gear is well worth the price.


SSTV with the Robot 1200C Scan Converter and the Martin Emmerson EPROM Version 4.0

by Dick Goodman WA3USG

Slow-scan television (SSTV) has evolved slowly but steadily in the last several years. Various transmission and reception standards have come and gone. Several companies have produced SSTV equipment and then disappeared from the scene. One company has been a mainstay in the field of SSTV: Robot Research of San Diego, California, manufacturer of the Robot 1200C scan con-verier (Photo A). While Robot's "bread and butter" is no longer in the amateur field, they still periodically schedule production runs of the 1200C.

Approximately three years ago, Ben Blish N4EJI (now AA7AS) created an SSTV system called the "Black Belt System" based on the Amiga 500/2000 computer. The Amiga Video Terminal (AVT) contains all current modes of SSTV, including those of Robot. It also includes its own special AVT protocol that proved superior to Robot. The complete AVT system is presently being marketed by AEA and is an excellent way to enter the wonderful world of SSTV. As new standards and protocols are developed, they may be easily incorporated into the AVT software.

There are other SSTV systems available. Research and development by other companies is moving at a dynamic pace, but at this time Robot and the AVT system are neck and neck in the forefront of SSTV technology. If there is an advantage of one system over the other, I would say it is in the field of marketing. The AVT system is being sold by AEA and other dealers. It has national advertising and support. Pick up a copy of virtually any amateur radio magazine and the AVT system will be advertised Robot Research has limited exposure. The Robot 1200C is currently available from PC Electronics in Arcadia, California. Robot Research will also take orders directly at the factory.

With the impressive capability of the AVT system, its national exposure. and the ease of updates to the software. I felt that it was going to rapidly become the dominant SSTV format. Then Martin Emmerson G30OQD of Bromley, Kent, England, developed an updated EPROM for the Robot 1200C that incorporated virtually all existing SSTV modes including those used in the AVT system.

Robot 1200C Basics

The Robot 1200C scan converter is a complete, stand-alone SSTV system that requires only a video camera, radio transceiver, and television set (or video monitor) for operation. It does not require a computer. With these items, full color, high resolution pictures may be sent and received from virtually anywhere in the world.

Unfortunately, Robot decided not to support anything other than Robot modes of SSTV. This caused few problems when only Robot SSTV systems were available, but as time passed other systems were developed. An example of this is the Volker-Wrasse system used by European and other DX stations. This was incompatible with any Robot SSTV system, including the 1200C.

Even with these shortcomings, the Robot 1200C survived. While not as sophisticated as the AVT system, the Robot 1200C required very little additional equipment for its operation, It also contained a video digitizer that allowed grabbing full color frames from any video source. These frames may be stored in the Robot's internal memory and displayed on any television. The picture may also be transmitted, via the connected radio transceiver, anywhere that voice contact is possible. That's pretty impressive for a box about 11" x 4" x 12". The AVT system needs an Amiga computer along with the AVT SSTV hardware and software, If pictures from a video camera are to be sent, you must also get a video digitizer board and install it in the Amiga.

What makes the Robot 1200C incompatible with other SSTV systems is the program stored in its internal EPROM but this program could be rewritten to add other SSTV protocols, stored on a new EPROM, and put in place of the original Robot EPROM.

Modernizing the Robot 1200


Obr.: Photo B. The Martin Emmerson EPROM Version 4.0, crystal controlled oscillator board and the optional parallel port board for the IBM PC.

The Martin Emmerson EPROM Version 4.0 (Photo B) contains all existing Robot modes and virtually all current SSTV formats used anywhere in the world! Its additional features may be controlled from the front panel of the Robot 1200C, or operated remotely with enhanced features via computer control. It should be stressed, however, that a computer is not necessary to use any of the new SSTV modes.

To take advantage of all the features of the new EPROM, the Robot 1200C must be modified. The procedure is not difficult but. as with all Robot-related modifications, documentation is difficult to come by.

The procedure is basically threefold. First, unplug the original Robot EPROM and plug in the new Version 4.0 EPROM in its place. Second, install a crystal-controlled oscillator board (see Photo B). This involves removing a chip from the Robot, plugging the oscillator board into the empty socket, and placing the removed chip in a socket provided on the oscillator board. Third, replace all 64K memory chips in the Robot with 256K RAM ICs. This last modification also involves soldering a series of jumper wires to the Robot's motherboard, changing a jumper pin, and replacing an IC. Depending on the production run of the Robot, the !C may have to be unsoldered. The entire modification took me about two hours (I had to unsolder the IC).

Once the modification is complete. the Robot has the capability to store four high resolution color pictures in its internal memory (instead of one picture). This memory can also be used by Robot control programs (with an IBM compatible computer) for truly spectacular capabilities and special effects. More about this later.


Obr.: Photo C. Comparisons of Robot 72-second, Scottie S1 and AVT 94-second pictures as received over a noisy UHF FM path. (This display and labelling was done with the Hi-Res f.4 control program.)

Obr.: Photo D. SSTV reception from Jim K4TGC on 14.233 MHz, using 36-second Robot protocol.

Obr.: Photo E. WA3USG's family, transmitted on 2 meters and relayed back over a 35-mile path.

The Emmerson EPROM

I ordered the Martin Emmerson EPROM directly from Mr. Emmerson in England. It took about six weeks to arrive as it was just coming out of beta testing, The EPROM is customized with your callsign, so it can be used only by the owner It is apparent that Mr. Emmerson put quite a bit of effort into the development of the program on this EPROM. This "customizing" will prevent users from copying the EPROM and passing it on (unless you want others on the air displaying your callsign). I feel that the price for this chip is in line with what it will do.

I also ordered the crystal oscillator board from Mr. Emmerson. The EPROM and oscillator board arrived intact from England, packaged ruggedly for shipment. The documentation provided is adequate, it consists of 12 high quality typewritten pages and several diagrams. Installation instructions are reasonably clear if you have any questions, get on 14.230 or 14.233 MHz and holler for help. I can almost guarantee that during virtually any waking hour, there will be someone on frequency who has performed this modification! Instructions are also provided for replacing the 64K RAM with 256K chips.

What will the Martin Emmerson Version 4.0 EPROM do, once it is installed and all modifications are complete? All Robot modes are left completely intact and functional, and you will have many new ones. The four Scottie modes are used by many DX stations and US stations. It is not unusual to hear stations exchanging pictures, using the Scottie modes for hours at a time. It is interesting to compare the Robot modes with that of Scottie, In almost every instance, a picture received will look noticeably better when received via the Scottie mode, as opposed to the Robot protocol.

There are also the Martin and Wraase modes. These are used primarily by DX stations and are not as popular as Scottie.

Finally, there are the AVT modes Two are provided: the 94-second and the 188-second. Each of these modes has a QRM and narrow bandwidth toggle fas does the actual AVT system). Pictures sent and received in the AVT modes are, in my opinion, the best of all protocols! Noise and QRM affect the received picture much less noticeably than in the other modes.

White difficult to objectively quantify, I ran some experiments on a UHF path of about 35 miles. I used frequency modulation, and carefully controlled signal levels to yield approximately 50% quieting. The S-meter was constantly observed to assure compliance to a controlled standard. Ken Starck WB3AXC, using a Robot 1200C, digitized a picture of himself and sent it in Robot 72-second color, Scottie S1, and AVT 94-second. Each picture was saved in one of the four internal Robot memories. Photo C shows the results of this experiment. The difference between these modes on HF using SSB are even more dramatic. Documenting and recording these differences is difficult, however, as conditions on HF change drastically from one moment to the next.

The Results

Perhaps the best thing about the Martin Emmerson EPROM is that it makes the Robot 100% compatible with virtually any SSTV standard in existence. The picture quality in any of these modes can be very good indeed. Photo D shows a picture received on 14.230 MHz from Jim K4TGC in Pulaski. Tennessee, using 36-second Robot protocol Conditions were good and there was very little interference. Photo E is a relayed picture of my family that I transmitted to another station on 2 meters The other station, located about 35 miles away, stored my picture in the Robot's internal memory and sent it back.

The Robot 1200C with the Martin Emmerson EPROM really shines when used under the control of an IBM compatible computer and proper Robot control software. The Robot 1200C has a rear-mounted parallel port, using a DB-25 connector, that may be interfaced with a PC clone.

To take advantage of this feature, a special parallel interface board must be installed in your computer (Photo B). I purchased mine from Martin Emmerson, but as of this writing others may be available that will work equally well, [Ed. Note: Another appropriate parallel interface board is the PIO-12 made by Keithley Metrabyte Corporation. 440 Myles Standish Blvd., Taunton MA 02780. Phone: (508) 880-3000.]. Inquiring on 14.230 MHz will also yield information on other possible manufacturers A cable connects the interface board in the computer to the Robot rear parallel connector.

There are several excellent Robot control programs on the market that are a subject in themselves Basically, these programs allow the operator to enhance the operation of the Robot 1200C. Pictures saved in Robot memory may be manipulated, changed in size, and cut and pasted with other pictures. Pictures may also be saved as disk files for permanent storage and recall. Hits in the picture as a result of noise or fades may be eliminated or minimized.

Special test patterns and graphics may be called up and displayed and transmitted The picture shown in Photo C was composed with a PC and a Robot control program called "Hi-Res, Version 1.4" by Tom Jenkins N9AMR. The Robot may also be commanded into transmit or receive, SSTV modes changed, and video inputs/outputs selected. Other popular control programs are SCAN (written by Bert Beyt W5ZR), SSTV (originally written by Jim Williams KC5VC, modified by G4UKL and now offered by Garnet "Beb" Bebermeyer WB0UNB) and IMAGE (offered by Dick Isely WD9GIG). These control programs offer different features and really expand the capabilities of the Robot 1200C.

In summary, the Robot 1200C is the only true stand-alone SSTV system available. With it, a video camera, and a transceiver, you have a complete SSTV system Alt that is required is a connection to the receiver's audio, transmitter audio in, and video in from any video camera. A conventional color TV or video monitor will display the captured pictures.

Computer control options for the Robot 1200C
Hardware
Parallel Board (for IBM PC control of the Robot) Martin Ernmerson Board (see address above
75 English pounds, or equivalent
Miscellaneous 256K memory chips @ $4 each, 18 required (various sources),
SSTV Software (Robot 1200 control programs for the IBM PC or clone)
Hi-Res, Version 1.4 $75 Tom Jenkins N9AMR, 5968 S. Keystone Ave., Indianapolis IN 46227 (317) 784-6118
SCAN, Version 6.0 $20 Bert Beyt W5ZR, 301 Tampico St., New Iberia LA 70560
SSTV $20 Garnet Bebermeyer WB0UNB. 15 Almeda Ct., Fenton MO 63026, (314) 343-8122.
IMAGE $27Dick Isely WD9GIG 736 Fellow St., St. Charles IL 60174

The Robot 1200C is capable of capturing full color video frames from any NTSC color camera, such as a camcorder. It will also function well with monochrome cameras. It is possible, using red, blue, and green filters, to store and send full color pictures using only a monochrome camera. With the modifications described, it will hold up to four high resolution color images in its internal memory. These may be images received off the air, or images captured from your camera, It will store up to 12 low resolution images, such as eight-second black-and-white pictures. All SSTV modes may be selected from the front panel without a computer. The addition of the Martin Emmerson EPROM Version 4.0 has updated the Robot 1200C to a state-of-the-art SSTV system, second to none.

I would be happy to answer any questions in reference to the EPROM Version 4.0 or the Robot 1200C. I hope to hear some new voices on 14.230 or 14.233 MHz. SSTV takes place daily on these frequencies. Drop on by and give a call, someone will be there to help you.

Contact Dick Goodman WA3USG at 199 Maple Lane, Mechanicsburg PA 17055. Please send an SASE for any information you request.