Getting Started in SSTV:
Part 2, the Sequel

by Sumner, W1VIV
[email protected]

In my previous article, (The Framingham Circuit, September 1997) [If you missed this you can see it on the FARA web site -ed.] I wrote about my long time fascination with the concept of Slow Scan Television (SSTV).  I wrote about how I built my first SSTV monitor about 25 years ago, and how crude it was, and how everything today is done by computer.  These days, hams are sending and receiving beautiful high resolution, full color pictures!  I wrote about my use of the K3BC software, and that, although I have been receiving pictures for about a year, I hadn't yet reached a point of confidence in my understanding of the software where I was ready to start transmitting yet.  Well, I finally did, and I have been on the air for a month or so happily sending pictures. 
The pictures have come from several sources.  Most have been downloaded from the Internet, in JPEG format.  A few were taken with my camera and developed onto a diskette.  This typically costs only $3.99 extra when you are having a roll of film  developed, and you get the prints as well.  Using a shareware program called Graphic Workshop, I can  convert them to bitmaps.  Then, using Microsoft's Paint program that comes with Windows 95, I can modify the bitmaps.  Sometimes I erase the backgrounds, sometimes I add items from

another picture, and I also can add my call letters, "CQ SSTV", etc.  Am I then ready to send them?  Not quite.  First, saving the modified picture, I have to go back to Graphic Workshop and convert it back to JPEG, and increase the file size to over 920,000 bytes which is required, (most pictures have lower resolution) and provides the  required format of 640 by 480 with 24-bit color.  Then, I convert it to a TIF file, and then click and drag it into my TV subdirectory.  Finally, going back to the K3BC software, I can convert the picture into a slow scan TV format such as Martin 1 or Scottie 1.  All this sounds complicated, but only takes a few minutes.  In fact, the most fun to me is not receiving or transmitting the pictures, but creating them! 
There was one electrical addition that was required.  A coupling transformer was needed to connect the audio coming from my serial (RS-232) port to the audio input of my transceiver.  Since you don't want rf feedback, it is advisable to avoid your microphone  input and to use the phone patch audio input on the rear panel.  Ben Vester's (K3BC) series of articles in QST called for an audio output transformer with an 8 ohm secondary.  Unfortunately, my Yaesu FT-990 internally ties the microphone input to the phone patch input, and the low impedance transformer winding loaded my mike input so much that I couldn't use the vox.  Substituting a 600 ohm 1 to 1 audio isolation transformer solved this problem, and I was finally on the air!

I want to thank Leo, WA1HAM, for all of his assistance.  He has been using the same software for some time and had the problems all solved.  He  also gave me a copy of Graphic Workshop, and patiently "elmered" me up the learning curve.  Thanks, Leo! 
Slowscan TV is now a major ham radio interest for me.  It's old fashioned ragchewing with pictures added, which makes the contacts much more interesting.  Here are samples of typical SSTV pictures.
Author's note:
This article was written a couple of months ago, but you can't stop progress.  I have now switched from the above MS-DOS program to one written especially for Windows 95.  Rather than using the RS-232 serial  port, it uses a sound card interface.  A big advantage of the Windows program is that you can be modifying one picture (writing on it, etc.) while receiving or sending  another  picture.  Ain't technology great?

This Month's Meeting

by Jim, W1EQW
Club President

A number of club members have requested that FARA spend some time at one of its monthly meetings on the subject of antennas, especially HF antennas.  With the onset of Sunspot Cycle 23, this is probably a timely topic and a great way to start off the new year.  (It's 5 degrees F with several inches of snow on the ground as I write this, so I'd say we're well into antenna season.) Because there is so much talent in FARA on any ham related topic, or just about any topic for that matter, it seems that an open forum discussion on HF antennas would make for an interesting meeting.  We'll give it a try at the January 8 meeting.  So I urge everyone to bring your antenna questions as well as your expertise on the subject of HF antennas.  Sharing "lessons earned" would also be welcome. We'll cover as much as we can in about 45 minutes including advantages/disadvantages of various types of antennas (yagis, dipoles, beverage, multiband), space limitations, dollar limitations, safety issues, and more.