Subject: Slow Scan Television (SSTV)

By far the most enjoyable new mode in Ham Radio is SSTV. But it is not new and it is not Television, per se. If you want to get started in Slow Scan or want to start again, the following is a quick recap.

SSTV is analog facsimile. Facsimile is a method of producing a picture a line-at-a-time. Newspapers and the wire press (e.g., AP, Reuters, UP) use facsimile for photos and text via wire and radio. Facsimile uses a line scanning system. The more lines, hence more time taken to send them, creates sharper better defined images. Line scanning is a very old concept. It is used in infra-red mapping and military reconnaissance. Artists have used the concept to copy graphic images freehand. Ham Radio Video is a compromise system that runs fast enough to produce attractive -- sometimes very beautiful -- pictures.

Slow Scan pictures used in amateur radio can be sent in a variety of time formats. Simple black-and-white photos of low resolution can be sent in 8 1/2 seconds. Good quality pictures in B/W or Color can be sent in one to three minutes. Excellent pictures in Color can be sent in about four minutes. Standard resolution of a picture today is a 640 width x 480 height pixels with 24-Bit color. 24-Bit color (also known as TrueColor) is able to reproduce up 17 million different hues. These are minute variations of eight basic colors like red, yellow, green, blue, white, black, magenta, and cyan. In short today's Slow Scan pictures using formats like Scottie #1 or Martin #1 are quite stunning! There are fifty or more time-formats created by many different programmers.

So now, you should be confused! Yes, Slow Scan is actually Faster than facsimile but slower than standard Television! You can use the longer formats like Scottie DX or WRASSE 180 (4-5 minutes) and receive beautiful pictures even in poor receiving conditions. By now, you probably have heard SSTV on 14.230-233 MHz or 7173 MHz. You can learn a lot by listening. Don't invest in Slow Scan until you have learned something about it from people who know what they are talking about. Newcomers have many erroneous ideas about the Mode and will be poor tutors. Old-timers who own ROBOTS are of little help if they have not become expert users of PCs and use the SSTV PC Programs routinely.

An amateur by the name of Copthorne MacDonald (1960s) originally developed what is today erroneously called SSTV. The name Slow Scan (a form of facsimile) is so named to contrast it to amateur radio's Fast Scan TV .

In summary, Amateur TV is called Fast Scan since it is virtually real-time much like your TV in the living room.  But regular TV requires a great deal of bandwidth because moving pictures require many frames per second. Slow Scan, using an audio spectrum of 1200Hz to 2300Hz width can send high resolution color STILL pictures around the world almost instantly. In conclusion, let's call it Slow Scan Video, instead! It aint TV, Pilgrims!

WHERE SLOW SCAN VIDEO IS TODAY

About 1992-93, as the Personal Computer began to appear in ham shacks, Slow Scan was no longer an expensive, experimentalist, elitist activity. Prior to that time an expensive converter built by ROBOT RESEARCH company was the only way to receive and send Slow Scan. After several years of PC programs, written by radio amateurs who were also involved in programming, the mode leaped forward in popularity as Microsoft Windows and INTEL opened up new and better PC performance, especially in CPU speed and better color and sharper resolution.

As more and more programs have been written and introduced, it has become evident that programmers are using about the same basic techniques for producing pictures. There are vast differences, however, in how the operator controls and manages the program. File management, slant correction and other calibration routines can be cumbersome, inconvenient and time-wasting. So, don't decide on which program is best for you merely based upon how the picture looks. And beware of the guy who started SSV a few months ago and who now believes he is an expert.They are all well-intentioned guys who want to help but always get a second opinion on some aspects of this interesting mode.

DOS-ONLY PROGRAMS

If you have a PC that is slow (under 100MHz), the SSV programs for DOS should be your choice. A number of them exist although most Video enthusiasts have moved on to Windows programs. I use MSCAN v2.10e, v2.11g and the latest v2.30 when using the DOS environment. These are multi-featured programs with excellent color and resolution. You must have a TrueColor 24-bit video board to run these programs. The reason Windows-compatible programs have become so popular is due to using the PC Sound Card as a converter. A converter or interface for DOS operation can be built for about $20.00 or one can be purchased for about $35.00-$50.00.

WINDOWS Slow Scan Video

If you are operating Windows 95 or 98, preferably at a CPU speed of 133MHz or higher, you will have a number of software choices. Although we have used every major Video program created in Europe and the USA, we have always had greater success with MSCAN programs, created by Mike Versteeg (PA3GPY). Mike is an entrepreneur whose small company, CombiTech, serves a world-wide market. Slow Scan and Weather Facsimile for boat owners, is Mike's full-time occupation. He has recently introduced MSCAN v3.11 that uses the PC Sound Board as an interface or converter. The last version was v3.13. Mike can be reached via his Website (http://www.mscan.com). Price: $50.00

(UPDATE:  In year 2002, the popular choice is MMSSTV by Mako Mora (JE3HHT), a Free program that includes all the best features developed by earlier programmers. Unfortunately, it does not include on On-Screen Editor for direct entry of text messages, so I still give MSCAN the edge yet, altho it and the other programs have some catching up to equal the features and reliability of MMSSTV which many have nicknamed MICKEY MOUSE !)

CombiTech led the way in bringing TrueColor 24-Bit images and Repeater Operations to Slow Scan. The resizable frames, one for Outgoing pix and one for Incoming pix -- both available on-screen at the same time -- offer the user the most efficient customizable system available. While receiving a picture, you can load another one to send and print messages directly on the picture in a wide variety of fonts and colors. His automatic slant calibration system is virtually fool-proof. MSCAN presents on-screen only that which is necessary to operate. It offers an uncluttered screen. The rest is done with drop-down menus. Beware of programs that present bright, busy screens full of stuff you don't need all the time. Since you will be looking at SSVideo many hours, to reduce eyestrain, go to Control Panel and set up (in APPEARANCE) a Black, or Dark, background with White or Yellow fonts.It is called Hi-Contrast. You can increase the size of the fonts to your liking. Force yourself to get used to it for the sake of eyesight conservation.

The SSTV32 program and JVCOMM32 offer somewhat similar dual frames but seem to be more complex compared to MSCAN. One of the more popular programs is CHROMAPix http://www.siliconpixels.com). Although you cannot keep both frames on the screen simultaneously, an Outgoing frame can be called forward. Price: $120.00

BOTTOM LINE: Try as many programs as you can, then decide. Each program has a certain appeal to certain people. Most of the major programs can be downloaded from the authors' websites. Each author has his own way of reminding you that you should Register and pay a registration fee. Upgrades are usually free, except when a major change has been made.

RANKING of POPULAR PROGRAMS (based upon current experience)

Frankly, trying to identify the so-called BEST program is a waste of time. Unless you are prepared to run comparative tests in a laboratory, closed-circuit setup, forget it! Slow Scan Video involves many variables such as propagation effects, differences in the sending stations' equipment, operator expertise, power levels -- and many more. You can be sure of the following:

2. Many programs are laid out on the screen in different ways: selecting the one you prefer depends upon your personal preferences. Subjective issues of this kind depend on  your mental makeup, education, etc.

3. Give preference to the program that always identifies who is sending the picture. Use only ONE WAY to identify, not two or three. Don't use the CW Identifier; it is not required in the USA. It wastes time and fouls-up the process. It wastes valuable time on-the-air! Normally, a number of stations are present on an SSTV channel and sharing time efficiently is desirable.

4. Find the program that uses the simplest and most reliable way to Calibrate, especially setting the SLANT CORRECTION offset.

5. Choose the one that is enjoyable for you to run -- meaning both Receive and Send.

WHERE TO GO ON THE INTERNET

The most comprehensive info source for Slow Scan Video in the USA is http://www.kiva.net/~djones by KB4YZ (Dave). Or go to any Search Engine and type:  SSTV.

We have spent only twelve years in Slow Scan, starting with MFJ1278 (bad choice!) and (later) the ROBOT 1200C. We have lived through the period of change from ROBOT days into using PCs. As product consultant for thirty years, we try to give guidance based upon hands-on experience. If I have not operated a particular program or piece of equipment, I may be able to steer you in the direction of a reliable person who can help you. You can ask for help and guidance on any SSTV channel and you will find lots of help.

I began in Ham Radio as an SWL in 1931, was licensed after WWII in 1947-48. At 82, I have a great affection for the Amateur Radio Hobby/Service. In closing, I appeal to you to promote the proper use of Slow Scan by keeping the material being transmitted both CLEAN and WHOLESOME. Abuse of our license privileges will only lead to loss of those privileges and the loss of respect and support of members of Congress, ARRL and the FCC. SSVideo should be a family-oriented interest. If a picture is the sort that you would not hesitate to show to a mixed group of men, women and children -- then that is a family-oriented picture!  

The source of these articles regularly carries the American Radio Alliance Group's subsite. However, the ARAG's Archive listings are available at that site. Should you want to read any of the listed articles and you cannot find them, contact me via csfranklyn@hotmail.com and I will try to place them on the Active Directory for your use. You can download it and keep it. Do not try to print it, however, since we use a Black background and White fonts which most printers do not like. Capture the text only, put it into WORD7, then you can print it.

 Enjoy SSVideo! 

de Cholly (W3OHV)

(updated July 2008)