Sorry for the delay in getting you this update. My move to Indianapolis set me back about two months, but I am back on the air and finally starting to respond to those of you who I promised program updates. Thanks for all the fine feedback on the program. I very much wanted this to be a successful project and appreciate your help in achieving that goal. The newest versions support 36 second color. 2.5 has S1 and S2 transmit enabled. No guarantees on these Scotty modes. You will need to tweek their PXTMs and TLS parameters to get the picture straight when received by a ROBOT. Clearly, the next step needs to be a low cost frame grabber. I have a novel idea which I will pursue as soon as I can empty some boxes and make room for my workbench. Until then, hang in there! ---------------------------- ViewPort VGA ------------------------------ Here is the 2.5 update of ViewPort VGA. Please make a backup of your previous version before loading this disk. Check your SSTV.CFG file to make sure that it contains the same parameters as the one included here. New Parameters have been added. ************************************************************************* XT USERS -> You MUST set the parameter XT to XT:1 in SSTV.CFG. If you do not, the system will default to AT and will lock up in most of the modes. ************************************************************************* VPVGA.EXE now includes ViewPort 32K which supports Swan Technolgies, United Solutions and Diamond Speedstar 32,768 (HiColor) Color VGA boards. I have added a parameter called HICOLOR which needs to be set to "0" if you have a 256 color board and "1" if you have a 32K color VGA. The bug which prevented some units from going into transmit has been fixed. Re-install U13 and you should be back in business. The unit should not go into transmit when you reboot the computer. I have fixed a bug which prevented you from changing LPT ports from within the program. I have one report that indicates that the system does not work on LPT2 even after changing the LPT parameter in SSTV.CFG. A few others reported that LPT2 works fine. Please let me know if this is still a problem!! I will get to the bottom of this! I am aware that you will have to reboot if you try to use your printer on the same port as the interface. I will fix this when I have a printer to test with. I have added the capability to read 24 bit TGA files. Load these with F7 as you would 15 bit TGA files. Some file conversion and paint packages only support the uncompressed 24 bit images, so you may find this useful. This version let's you quickly store 9 pictures on a RAMDRIVE or HARD disk. In response to KF4ZC's suggestion, you can now load pictures while viewing the directory listing. Good idea John! The notes now make it clearer how to load GEST and HIRES images. ********************************************************************* VERSION 2.3 includes 36 second color receive. This uses a new scheme to decode color sync pulses. I have only run it on my 20 Mhz 386, so please check it out and let me know what you find on your machine. Pictures will scan down in low resolution, but after you hit the return key to redraw them they will display as 256 X 240. I also shifted the color look-up-table to correct the pink 72 second color picture problem. Let me know how it looks now to you. ********************************************************************* Versions 1.9 and newer include major changes to the timing scheme which should make it portable between various speed PCs. I have done a decent, but not perfect job of setting the default parameters. SSTV.cfg still exists and you can try to improve on the defaults. Please let me know what you find when you run this on your PC. A WORD ABOUT SOFTWARE REVISIONS ------------------------------- I will make sure that A&A is kept up to date with software that correctly performs the functions advertised by them. The first release was 2.0. RELEASE 2.1 fixed a bug that prevented some units from going into transmit. A&A will ship this to new users. In the name of progress, software that I send from my QTH will be the latest version of the program and will include "minor" feature additions. I will do my best to make sure that bugs have not also slipped in, but no promises! This may cause a problem at first since someone will always seem to have a newer version. The readme file will describe the difference between Releases. I am going to leave it up to you to work out a way to get versions 2.1 thru 2.?? distributed. Currently, I ship a copy to KA8LWR who posts the update on the Kookie BBS in Ohio (419) 562-6327. I will help in anyway that I can as long as it does not mean shipping more than a few copies each week. The next version that I send to A&A will be RELEASE 3.0 and will include 36 second receive. History of Updates ------- 1.93 ) Added tuning tool. 2.0 ) Changed the name of the executable to VPVGA.EXE Added Hicolor.exe to support 32K color cards. 2.1 ) Fixed LPT selection function (I think?). Added 24 bit Targa (TGA) load. Combined VPVGA and HICOLOR into VPVGA.EXE Fixed bug in power on reset circuit. 2.2 Added 10 memories. Can load pictures while viewing directory. 2.3 Added 36 second color receive. Changed color look up table so that 72 second pictures are not pink. 2.4 Fixed the hang problem on 36 second receive. 2.5 C or c will convert between formats. Q or q will quit the program Added XT: parameter to sstv.cfg Added S1 and S2 transmit HARDWARE REQUIREMENTS --------------------- The system has been successfully tested on machines ranging from 4.77 Mhz XTs to 33 Mhz 486s. You may have to adjust some software parameters in SSTV.CFG if your machine is a 10Mhz XT or slower. Your PC must be %100 IBM compatible. I have run across 2 older XT designs which are not compatible with this program. These are missing a trace between the 8253 timer pin 17 and the 8255 PIO port pin 12. The designer started to run the trace, but either tied it to ground or left it floating. If you are running on a clone XT and the system hangs in the transmit mode, this is probably your problem. You must have at least 640K of memory, a printer port and a VGA display capable of 320 X 200 X 256 color mode. IMPORTANT: Your Printer interface must be jumpered for address 378 Hex if you want to use LPT1 or 278 Hex if you use LPT2. Some Parallel cards come strapped at a non-standard address. SOFTWARE REQUIRMENTS ____________________ The program may not work properly if you have other TSR programs such as SIDEKICK or TURBO LIGHTNING installed. Also, the program will not work with WINDOWS running. We are currently tracking down a problem that causes transmitted pictures to have a zig zag pattern when the program runs under DOS5.0 with a memory manager, mouse and hand scanner software installed. One of these is causing a problem. This will be solved by the time you get on the air. UPDATE: WW0F reports that the problem was caused by his logitech bus mouse. If you have one of these, you should not load its driver when you run ViewPort VGA. You must have the DOS program "MORE" installed and in your search path for the directory command to work. If the menus have black backgrounds behind the text, remove ANSI.SYS from your config.sys file. A program such as Alchemy mindworks Graphics Work Shop is recommended for converting and scaling GIF and PCX pictures. A program such as PC Paintbrush which supports 256 color PCX pictures can be used for editing pictures and adding graphics. INSTALLATION ------------ The interface connects to your parallel printer port using a male to male 25 conductor cable. As with any cable connected to a data port of your computer, this is likely to radiate RF energy that can couple into your receiver. I suggest that you make this cable as short as possible. I am using a 3 foot unshielded ribbon cable now with no problem. I have had trouble with an 8 foot cable of the same design. Looping that cable 3 times through a common mode choke (the deflection yoke from an old TV works great) helped. Of course you might also try a shielded cable connected to ground at one OR both ends. I take the audio output from my TS-530S headphone output. That way I am able to control the audio level into the box with my AF gain control. There are many other ways and I am sure you will find one that best suits your station configuration. I apply audio to the microphone input on my rig. HARDWARE ALIGNMENT ------------------ Incorrect alignment of the hardware interface can cause loss of sync and/or improper colors. What you are trying to do here is adjust the amplitude of the demodulated SSTV signal that is applied to the A/D converter. The goal is to get the sync tip (1200 Hz) at zero volts and the white peaks (2300) Hz at 5 volts. This can be measured while looping the TAPE output to the input and sending a gray scale. NOTE: The audio level at SSTV OUT may not be high enough to drive the demodulator. USE TAPE OUT! If you have a scope, connect it to TP3 and verify that the sync tips are at 0. White video should be 5 volts, or better yet equal to the 5 volt supply voltage (which may be 5 +/- 0.2 volts or so.) If you do not have a scope .... Connect the interface to your computer's printer port. Connect the modulator's tape output to the SSTV input with a jumper wire. Select the Loopback function from the SETUP menu. This causes the modulator to produce a sequence of 1200Hz, 1500Hz, 1900Hz and 2300Hz tones. The program reads the resulting values from the A/D and displays them graphically. Adjust RO and RV until the indicators line up with the corresponding arrow heads. Press the space bar to momentarily pause the program. The values displayed on the right side of the screen should be within +/- 4 of 0, 64, 160 and 255. ++++++++++++++++++++++++++ IMPORTANT NOTE ++++++++++++++++++++++++++++++++++++ NOTE: The cursers for sync and white should just barely reach 0 and 255. If you go beyond those points, you may not be able to set 1500 and 1900 Hz correctly. Those of you fortunate enough to have 486 machines, will need to set the machine in the slow mode (Non-Turbo) when running the loopback program. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ SOFTWARE ALIGNMENT - TIMING PARAMETERS -------------------------------------- The defaults parameters in SSTV.CFG should work quite well on most machines. If the RED, GREEN and BLUE color fields do not overlap, you will need to edit parameters in SSTV.CFG. To do so, you will need a text editor. The parameters include a name followed by a ":". Anything prior to the ":" is a comment. When a parameter name includes a number (e.g. PXTM36R), this refers to the BW speed of the ROBOT B/W - COLOR pairs. Here are the pairs: 8 BW 12 COLOR 12 BW 24 COLOR 24 BW 36 COLOR 36 BW 72 COLOR SO ... the parameter PXTM36R refers to a timing parameter which effects both 36 BW and 72 COLOR. The R and S suffixes refer to Receive and Send. TLS, TLP, LPXTM, TCS, TCP and PXTM are timing parameters: They function as follows: TLS: This is the duration of the luminance sync pulse. TLP: This is the duration of the luma back porch. LPXTM: This is the duration of one luma pixel. TCS: This is the duration of the chroma sync pulse. TCP: This is the duration of the chroma back porch. PXTM: This is the duration of one chroma pixel. ****************** ROBOT 72 SECOND COLOR WAVEFORM ********************** LUMA LUMA LUMA R-Y R-Y B-Y B-Y SYNC PORCH PIXELS SYNC PIXELS SYNC PIXELS | | ______________ ___________ _ ___________ | | ___| |/ \___| | ---\ /-------|______________|\_/ |___________| |___________| - \ / -LSUP | | | \--/ R-Y B-Y | PORCH PORCH LSDN TLS TLP LPXTM TCS TCP PXTM TCS TCP PXTM ************************************************************************* The number after the ":" is a value related to the PC's internal time base. The software is quite portable among machines ranging from 10 Mhz XTs to 33 Mhz 486s. The default parameters in sstv.cfg are based on a 20 Mhz 386 with cache. Machines slower than 10 Mhz XTs will require some changes in SSTV.CFG. SEE LSYFILT AND CSYFILT DESCRIPTION BELOW!! Even on some faster machines, some of you will notice color shifting and will want to fine tune the default parameters. Here is how I suggest you do this. You will need a tape of a strong SSTV signal for each receive mode to be adjusted. The picture should include objects that let you identify exactly the leftmost and rightmost column of pixels. For best results, use your VCR to record this audio. These instructions will refer to alignment of the 72 second color mode. Load the gray scale test pattern from the Additional Functions Menu. Mark the rightmost edge of the white bar with a marker or tape. Load the color bar test pattern from the Additional Functions Menu. Mark the leftmost edge of the white bar with a marker or tape. STEP 1 ------ The object of this first step is to receive the B/W portion of the color picture such that the first column of pixels is displayed in the first column of the display. The ROBOT color modes include a time interval called the Luminance Porch between the end of luminance sync and the first pixel on a line. After detecting the end of the sync pulse, the software waits for a period determined by the value of TLP before sampling the first pixel. Replay the 72 second color picture and receive it in 36 second B/W. If the first column of pixels is not displayed in the first column of the display (which was marked on your CRT in a previous step), increase or decrease TLP36R until it does. STEP 2 ------ The object of this step is to receive the B/W portion of the color picture such that the last column of pixels is displayed in the last column of the display. Replay the 72 second color picture and receive it in 36 second B/W. If the last column of pixels is not displayed in the last column of the display (which was marked on your CRT in a previous step), increase or decrease LPXTM36R until it does. DO NOT proceed to the next steps until steps 1 & 2 until the B/W picture EXACTLY fills your screen! STEP 3 ------ Now that the luminance portion of the picture EXACTLY fills the screen, you can proceed to overlay the color information pixel for pixel on top of the luminance portion. The ROBOT color modes include a time interval called the Chrominance Porch between the end of Chrominance sync (R-Y or B-Y) and the first Chroma pixel on a line. After detecting the end of the sync pulse, the software waits for a period determined by the value of TCP before sampling the first chroma pixel. Play back the 72 second color picture and receive it in 72 second color. From the SETUP menu, view the luminance portion of the picture and locate an object within 1 inch of the left side of the display. Mark its position. View the R-Y portion. If the position of the R-Y portion of the object does not overlay the Luminance portion of the object, adjust TCP until it does. STEP 4 ------ Play back the 72 second color picture and receive it in 72 second color. From the SETUP menu, view the luminance portion of the picture and locate an object within 1 inch of the right side of the display. Mark its position. View the R-Y portion. If the position of the R-Y portion of the object does not overlay the Luminance portion of the object, adjust PXTM until it does. I would not be surprised if you found the above procedure cumbersome. Once upon a time, every machine needed major adjustments to receive any kind of color picture. Painful as it was, the first users were always able to set the timing parameters properly and learned alot about the SSTV formats in the process. This software should only require minor tweeks if any. SOFTWARE ALIGNMENT - OTHER PARAMETERS -------------------------------------- LSUP, LSDN, RYUP, RYDN, BYUP and BYDN are threshold levels which you might want to play with. A look at the loopback program in action will tell you that a luma sync pulse causes the output of the A/D to fall from about 64 to 0. LSDN (Luma Sync Down) is the threshold below which the program determines the falling edge of luma sync. I don't think this value is very critical and have put it at decimal 40. LSUP is very critical since it is used to determine when the sync pulse has risen to the back porch level of 64. This number must be high enough so that noise during sync does not rise above it, and low enough so that it is exceeded even if the radio is detuned slightly. Decimal 40 works well so far. Given that 1900 Hz is the chroma porch level, I will let you figure out what RYSUP, RYSDN, BYSUP and BYSDN are and why they default to the values in sstv.cfg. ********************** IMPORTANT NOTES FOR XT USERS ********************** Change XT:0 to XT:1 in sstv.cfg if your machine is an XT. LSYFILT sync filter parameter - This parameter determines how many consecutive samples must be below the sync threshold LSDN to recognize a sync pulse. I found that numbers between 64 and 128 work well on my 20 Mhz 386. LSYFILT will have to be reduced on slower machines. Its up to you to find a value that works best. If you suspect a problem here, just make it 8 - 16 and work up from there. LSYFILT can best be set while receiving a BW or Scotty picture. CSYFILT chroma sync filter parameter - This parameter determines how many consecutive samples must be below/above the chroma sync thresholds to be recognized as a chroma sync pulse. Theoretically, CSYFILT should be 1/2 LSYFILT but I have found that a much smaller value is needed. If you suspect problems here, just start with a value of 4 - 8 and work up from there. CSTRIES parameter - This parameter determines the number of times the software will try to detect a chroma sync pulse before dropping the current line pair. CSYTRIES will be used for 36 second color receive only. ****** You WILL have to change LSYFILT and CSYFILT on slower XTs. ********** At this time, my recommendation is to set CSYFILT = 4, LSYFILT = 8 and CSYTRIES = 4 for XTs slower than 10Mhz. This will get the receiver up and running. Try increasing CSYFILT and LSYFILT until the receiver stops working reliably, then back off some on each. Higher numbers for these two parameters will result in better noise immunity. For clock speeds below 10 Mhz, also set PXTM36S = 625 and TCP36S = 1775. This should result in better color registration on 72 second transmit. COLOR:[0 or 1] The menus should have white text on colored backgrounds. On some VGA cards, the text will appear against a black background. I think this looks ugly, so you can turn the color off by changing the COLOR parameter in sstv.cfg to COLOR:0. UPDATE: Thanks again to WW0F for tracking down this problem. It seems that the black backrounds only show up if you have ANSI.SYS installed via your config.sys file. You don't need ANSI.SYS for many applications, so I suggest you create an alternate config.sys to use only when ANSI.SYS is needed. LPT:[1 or 2] Set LPT to a 1 or 2 to set the default printer port to LPT1 or LPT2. HICOLOR:[0 or 1] Set HICOLOR to 0 for 256 color VGA boards. Set HICOLOR to 1 if you have a SWAN, UNITED SOLUTIONS or DIAMOND SPEEDSTAR 32K color HiColor (TM) VGA board. ABOUT THE MENUS --------------- There are four menus. Toggle between the RECEIVE and TRANSMIT menus with the 'r' and 't' keys. Switch to the ADDITIONAL FUNCTIONS MENU by pressing ESC. Press F10 at the ADDITIONAL FUNCTIONS menu to switch to the SETUP menu. The key assignment isn't bad if your function keys are horizontal on your keyboard. The first 4 keys are the B/W modes, the next group of four are the ROBOT color and the last group of four are Scottie and Martin. If your keyboard does not have an F11 or F12 key, use 'm' for Martin 1 and 'M' for Martin 2. In a few minutes, you will know what keys to press without even looking at the menus. BW COLOR NEW MODES 8 12 24 36 12 24 36 72 S1 S2 M1 M2 If you have two vertical rows of function keys and find this awkward let me know and I will provide an alternative key assignment. NOTE: K4FJK just informed me that his XT BIOS does not support F11 and F12 even though they are on his keyboard. XT users may need to use 'm' and 'M' for the Martin modes. Those of you with 4.77 Mhz or 8 Mhz XTs may find it a bit annoying that the menu screens repaint each time you return to them. I do not know how to avoid this since the 320 X 200 mode overwrites the text pages and they need to be refreshed. Perhaps this is a good excuse to buy a faster machine!! NOTE: Some stations have found an intermittent problem that does not allow them to quit the program with the 'Q' key. KA8LWR found that his logitech mouse driver was the cause. Any other feedback?? Any comments about the user interface are very much welcomed! DIRECTORY LISTING ----------------- You can display a listing of picture files from the Additional Funtions Menu. The command "dir *.TGA | more" is executed when you select this function. "More" is an executable program that came with your DOS operating system. It must be installed and in your search path for the directory listing to work properly. Press 'L' if you want to load a picture while viewing the directory. LOADING PICTURES ---------------- Four picture file formats are currently supported: PCX: Zsoft's 256 color format. TGA: TrueVision's 16 bit 32K color uncompressed TARGA format. IMG: For you ROBOT owner's, GEST 184K images. HRZ: For you HIRES users, N9AMR's 184K images. Why these formats? I chose PCX over GIF as the 256 color format because it is easier and faster to decode and is compatible with the very popular PC Paintbrush program from Zsoft. GIF and other formats are easily converted to PCX with programs such as Alchemy Mindwork's Graphics Workshop or Bob Montgomery's VPIC. Since this system receives and transmits using 32 thousand colors, I support three popular 16 bit formats. These pictures take the most advantage of the system's capabilities. All of the 16 bit formats are in the raw (uncompressed) form because these were easier and faster to load. Since they also take up valuable disk space, I will plan on adding the compressed forms of these files also. TrueVision is an industry leader in video frame grabber's and PC plug in graphics boards. I think you will find the TGA format become more popular as the Hicolor VGA boards gain in popularity. ROBOT owners can use their ROBOTS as frame grabbers since ViewPort VGA can read GEST and HRZ images. PCX (SHIFT F7) --- 256 X 240 X 256 OR 256 X 200 X 256 color PCX files can be loaded. Use something like Alchemy's Graphics WorkShop 6.0 to Convert and Scale images to one of these formats. Use PC Paintbrush IV or better to add graphics. Scale to 256 X 240 X 256 if the image has more than 256 pixels AND more than 240 lines. Scale to 256 X 200 X 256 if the image has more than 256 pixels BUT less than 240 lines. For example: Using Graphics Workshop, scale a 640 X 480 X 256 color image to a 256 X 240 X 256 color image by scaling 40% Horizontal and 50% vertical and saving as a PCX file. Using Graphics WorkShop, scale a 320 X 200 X 256 color image to a 256 X 200 X 256 color image by scaling 80% Horizontal and 100% vertical and saving as a PCX file. The files will be displayed with an optimized color palette after the load. This is how they will look at the receiving end. If you go back to a menu and then hit "return" to bring the picture back to the screen, it will be loaded with a default palette and may look quite poor. However, it will still be transmitted with the optimized palette. Also, 256 X 200 images will fill the screen vertically when loaded. Transmitted pictures will be "padded" with 20 lines of black at the top and bottom of the screen. Hitting return will scale the 240 line image including the 40 black lines of padding down to the 200 lines on the VGA screen. This turns out to have less than 200 lines of real picture, but the transmitted picture will have 200 lines of real picture and 20 lines of black on the top and bottom. After loading a PCX image, wait for a tone before proceeding. This might take about 10 seconds on an XT, but only 3 or so on a 386. Perhaps next the version will also read and size 640 X 480 and 320 X 200 images directly. TGA (F7) --- I support the TGA file so that anyone who has a frame grabber capable of 32K colors can convert their files to TGA for input to ViewPort VGA. You will not find too many of these files on BBSs because they are quite large. IMPORTANT - the TARGA files must be Uncompressed 16 bit TGA files. Some programs such as Alchemy's Graphics WorkShop save compressed TGA files which will not work! GEST IMG (G) & HRZ (H) ---- GEST is a popular program which allows you to add text and graphics to pictures. It was written to control the ROBOT 1200C. Press 'G' at the Additional functions menu to load GEST images. HIRES is an even more popular program used to do anything imaginable to a ROBOT 1200C picture. Press 'H' at the Additional functions menu to load GEST images. GEST IMG and HIRES HRZ files must be the uncompressed variety (184K). LOADING WITH A CUSTOM COLOR PALETTE ----------------------------------- Even though the program receives a picture into memory with 32K colors, it can only be displayed with 256 colors. The question is ... which 256 colors does one use to represent those 32K colors received. While the picture is being received, it is displayed with a default palette chosen by me. Some pictures will look OK. Others could use some help. Pictures saved to disk can be retrieved in improved color mode from the Additional Functions menu. Load With Custom Palette calls a routine which determines a better 256 colors with which to represent the picture. Enter the file name without the extension when prompted to do so. A flashing star will indicate that the program is running. This routine takes about 30 seconds on my 20 Mhz 386, so be patient. Many received pictures will be improved significantly. Some will not look much better. 256 color PCX files will probably get trashed with this technique. The transmitted picture is not improved by using this load. The transmitted picture will always use 32K colors, so don't waste the time. This is only to DISPLAY a better picture! Keep your eyes open on a deal for a HICLOR VGA board. The Swan, United Solutions and Speedstar use Tseng Labs 4000 chip and cost about $160 with 1 Mbyte. VPVGA Release 2.1 supports these boards. Pictures are displayed in 256 colors as they are received. Pressing ENTER displays the picture in 32K colors in about 2 seconds. SAVING PICTURES TO DISK ----------------------- The current software can only save COLOR images. These are always saved as 123K TGA files. SAVING PICTURES TO MEMORY ------------------------- Version 2.2 also let's you save up to 9 pictures to memory for quick access. This is accomplished by creating a RAMDRIVE as described in your dos manual. Remember that pictures take about 123K bytes, so for 9 memories, your RAMDRIVE must be about 1.2 Megs. Also set the parameter called RAMDRIVE: to indicate the drive letter of your RAMDRIVE. (e. g. RAMDRIVE:d:). At the Transmit or Receive menu, press a number key between 1 and 9. The program prompts you to [L]oad or [S]ave and image to the specified RAMDRIVE. If you do not have additional memory in which to create a Ramdrive, set RAMDRIVE to your hard disk. This is still a convenient way to tuck away a picture with out having to type a file name! SENDING PICTURES ---------------- The B/W, 36 and 72 second color transmit modes are enabled. I think Scotty and Martin transmit is going to be a bit tricky. I have sent S1 to a ROBOT with this software running on a 33Mhz 386. I am sure I could also send S2, M1 and M2 on this machine. The problem is that these modes depend on a very accurate and stable oscillator. The ROBOT users install a special 12.00000 Mhz oscillator when they upgrade to these modes. We are not only stuck with the 95 cent oscillator in our PC's, but these also vary in frequency from 4.77 Mhz to 40 Mhz. You would have to make some very tricky adjustments to the SSTV.CFG file to make these modes work. I will be honest with you and tell you that I am not enabling these modes now because I want to see the first systems come up with as little confusion as possible. If we get on the air and send crooked pictures for a few hours at a time, many HAMS will be discouraged about this otherwise easy to build and use project. ************************************************************************** UPDATE: OK, some of you figured out that F9 actually does cause the system to transmit in S1. I was tempted to disable it in this version, but I know I will catch all sorts of flack from those of you who were able to get it to work if I do. PLEASE respect the many others who are listening in for pictures and do not take up alot of time on twenty meters sending crooked color bars while you play with parameters. Also, you need to understand that all Viewport VGA systems will copy other ViewPort VGA systems in S1 even if your parameters are not set correctly. Some AVT users may tell you that your S1 pictures are straight because they can manually adjust their parameters to match your incorrect parameters. The only good test is with a ROBOT 1200C! This version also converts ROBOT format to S1 so any pictures can be sent in Scotty mode. The conversion has some bugs but is not too bad. (I KNOW I am going to regret this!!). *************************************************************************** Load an image using the standard load functions. Do not include the extension when you specify the file name. The picture will be loaded in memory with 32K colors but will appear on the screen with only 256. Hit return and you will be returned to the red transmit menu. Press one of the function keys to transmit the picture. The system supports the Vertical Interval Signal (VIS) in the transmit mode. This tells scan converters such as the ROBOT and AVT system which mode is being sent. The speed being sent is displayed at the bottom of the menu during transmission. I do not re-display the picture during transmission because this would take several seconds on slow machines. Consult the user's manual for your rig to determine the maximum recommended power output for continuous duty cycle operation. Kenwood recommends 60 watts for the TS-530S. With your microphone level set for proper voice operation, transmit a gray scale and adjust the audio level control on the interface for the desired RF output. Press any key to abort transmission. RECEIVING A PICTURE ------------------- Modern SSTV transmission formats include a digital header (called a Vertical Interval Signal) to indicate to the receiver what mode is being sent. The current software does not support the VIS in the receive mode. Courteous SSTV operators will also identify the mode by voice before transmission. Listen for the sending station to send two short tones which signal the start of a picture. Press the appropriate function key to begin reception. Press any key during reception to abort. NOTE: The software only checks for a key during the sync interval. The system will hang if you try to receive with no input signal. If you are on the air, you may have to increase the receive audio or wiggle your receive dial to get out of the receive mode when no signal is present. The program uses the VGA's 320 pixels by 200 lines display mode. Modes that use 128 pixels by 120 lines are displayed in full. Modes with more than 200 lines will be received in full, but only the first 200 lines will be displayed. When the transmission is complete, press any key to return to the main menu. The received picture disappears from the screen, but is saved in memory. Press "ENTER" to re-display the picture. This time, the software "tosses out" every sixth scan line so that the entire picture fits on the 200 line display. You should be aware that since the VGA can display only 256 colors, a small error in frequency can result in a large error in color. The received picture will usually be too pink or too green if you are off frequency. A scope connected to TP3 makes a convenient tuning indicator. While receiving a slow scan signal, tune the rig so that the tips of the sync pulses are at zero volts. With practice, you will learn to tune in pictures without using the scope. Viewport VGA also supports KB9MC's zero beat tuning method. Pressing '+' while on the transmit menu sends 5 seconds of 1200 Hz. Pressing '+' while on the receive menu, generates a 1200 Hz tone from the computer's speaker. To tune to another station, ask him/her to send you their 1200 Hz tone. Press '+' at the receive menu and tune your receiver to zero beat the received tone against the tone from the PC's speaker. And if that is not enough ... ViewPort VGA also provides a real time visual tuning indicator. From the SETUP menu, select the Tuning Indicator utility. While the sending station sends you a constant 1500 or 1900 Hz tone, tune your radio until the cursor aligns at the 1500 or 1900 Hz arrow head. There are at least two more tuning aids I might add in the future. A real time oscilloscope display showing the demodulated waveform and built in frequency error correction that would allow you to be out of tune by 100 Hz or so and receive the picture correctly. UPDATE: Release 2.0 now includes an oscilloscope display. This is an added bonus which has had all of 15 minutes testing. Let me know what you find out. A white line marks the 1200 ans 2300 levels. This is actually one away from where the trace will be for 1200 and 2300 Hz. You should see one scan line of space between the trace and the markers at 1200 and 2300 Hz. Pressing the space bar freezes the display. Pressing 'q' quits. The scope displays one full scan line when run on a 20 Mhz 386. Let me know what happens on your machine. You should also be aware that the SSTV modes are susceptible to noise. In particular, when noise occurs during a sync pulse, the software might skip an entire scan line of the video. Noise which occurs during a scan line gets translated into video and typically appears as "snow". I have received "closed circuit" pictures with S7 to S9 signals and a noise level of about S3. Keep in mind that the overall signal to noise ratio is more important than the signal strength. SO WHAT MODES CAN IT COPY ------------------------- These receive modes are supported: ROBOT 8, 12, 24, and 36 second BW. ROBOT 36, 72 and S1, S2, M1 and M2 color receive. These transmit modes are supported: ROBOT 8, 12, 24, and 36 second BW. ROBOT 36 and 72 color. A WORD ABOUT THE NEWER MODES ---------------------------- I already explained why I do not support the Scottie and Martin transmit modes. So why is receive any different? Although these modes do not depend on a sync pulse for every scan line to keep the transmitter and receiver in sync, one is provided for each line. This, I assume is so that you can turn your receiver on in the middle of a picture and still sync up. ROBOTs and the AVT system do not need to decode subsequent sync pulses. They stay in sync by virtue of the fact that their oscillator exactly matches the transmitter's. Viewport VGA takes advantage of the sync pulses which are sent every line in order to keep in sync with Scottie and Martin modes without the need for an accurate oscillator. The cost we pay for this is the lack of noise immunity that ROBOTs and AVT systems can achieve with these modes. The original Scottie mode included 16 lines of gray scale at the top of the frame. These are tossed out when images are returned to the screen with the return key. NOTE: Some stations do not send the 16 lines of gray scale in S1. I am not sure what goes on here. Can someone explain? The RED field will be offset by one line while receiving Scottie modes. Pressing ENTER after receiving S1 or S2 fixes up the 1 line vertical shift in red. Pressing 'c' will convert a picture received in SCOTTY or MARTIN to the ROBOT format so that it can be retransmitted in 36 or 72. Scotty 1 images can be saved to disk. They are converted to ROBOT at this time. ---------------------------- NOTES AND UPDATES --------------------------------- 1) REMINDER: This system sends, receives and saves pictures using 32 thousand colors. It only displays 256 colors on your PC because of the limitation on the VGA card. Release 2.1 supports the newer Hicolor (32K) VGA boards. Keep your eyes open for one of these at a good price. 2) If you built a homebrew interface using my schematic and want to use this software, either: 1) Eliminate the section of U9 (pins 1 and 2) 2) Add another section of U9 (7414) in series with pins 1 and 2 of U9. Choice 2 above is preferred. 3) The software now supports the power on reset circuit. This circuit prevents the system from going into the transmit mode when you boot your computer. I found that you need to add a 1K resistor from the 25 pin connector pin 14 to +5 volts. NOTE: Newer units already include this resistor. If for any reason your interface intermittently drops out of the transmit mode, I suggest that you remove U13 and tie pin 11 to pin 5. This disables the reset circuit, so the system will try to key your rig while booting. Execute the program reset.exe early in your autoexec.bat file to return the system to receive if you have bypassed the reset circuit. 4) WARNING: This program stops your PC's real time clock for as long as you send or receive pictures. This might seem trivial, but if you spend as much time as I do playing Slow Scan, you could miss dinner! 5) For you guys that wanted 8 seconds to be continuous, here is a compromise. For 8 and 12 second B/W, pressing any key aborts, but pressing the mode key (F1 or F2) will start the frame at the top again w/o going back to the main menu. ???? WHAT COMES NEXT ???? Well, that depends alot on what I hear from you. Here are some things that I have in mind. Release 3 --------- 1) 36 second color receive (a fully tested version that receives full resolution on the first pass). Release 4 --------- 1) Vertical sync support on receive. Get used to setting RO and RV because that will be very critical here! 2) Scottie and Martin transmit. Release 5 --------- 1) Thanks to KA2PWM, I have an article in my hand that describes an undocumented VGA mode that supports 320 X 240 X 256!! This is great since the 256 X 240 ROBOT images will fit on the screen (and at the correct aspect ratio too)! Thanks Mike, I will do this when the smoke clears. Release 6 --------- 1) Integrated frame grabber. Any suggestions on which one? Would you build a real time frame 32K color frame grabber for about $200? 2) Real Scottie and Martin support using additional timing board. Release 7 --------- 1) AVT modes using an additional timing board. Release 8 --------- 1) Mouse interface 2) Experimental High resolution modes (640 X 480) in color or B/W. 3) Quad mode. 4) 8 and 12 second color. GOOD LUCK KA2PYJ John Montalbano (KA2PYJ) can be reached at: Often on 14230 Mhz during prime time or at ... 10646 106th Place Indianapolis Indiana 46033 Mail will also be forwarded from: 10 MacLeish Dr. Morganville, N.J 07751