PROGRAM SETUP ( Available in the Manual. If you do not have the Manual, print a copy of this file! )
It is important that all steps in this section be followed for proper program operation.
Multi-Tasking Considerations:
As a Windows program, WinPix Pro allows you to load multiple programs and switch between them easily. When a program is being loaded into memory, the activity of other programs is interupted during the loading process. It is therefore important that you do not LOAD another program while you are transmitting or receiving a picture. Load any other programs you want to use at any time the Monitor, Receive, or Transmit dialog boxes are not in use. Once a program has been loaded, you can switch to that program while transmitting or receiving a picture. The only other restriction on multi-tasking is the available memory and computer speed. If computer loading is close to 100 percent running another program during receive or transmit is not a good idea.
Telling Your System Your Time Zone:
In many cases your AUTOEXEC.BAT file already contains a line defining the TZ environment variable. This entry tells Windows your time zone. relative to the prime meridian (UTC). If you are in the central time zone and your area uses daylight savings time, you should add the following line to your AUTOEXEC.BAT file.
SET TZ=CST6CDT
This tells the system that you are in the Central Standard Time zone, six hours behind UTC and in summer you are on Central Daylight Time. Notice that there are no spaces before or after the "equals" sign. If you do not have the TZ environment variable set, and you elect to use the UTC time display, Windows 3.1 will usually default to pacific standard time which is 8 hours behind UTC. Other U.S. time zones include EST5EDT, MST7MDT, and PST8PDT. Alaska becomes UTC9 and Hawaii UTC10. Outside of the U.S. the entries continue to follow a form such as UTC0 for England and UTC-1 for Germany. The number is simply the number of hours behind UTC. In other words, when the number is added to your time the result is UTC.
Windows 95 Users:
The ease with which Windows 95 allows you to switch between running programs and loading new programs makes the ôAuxiliary Programsö portion of Programs/Default File Path setup discussed below rather unneccessary.
Users of Windows 95 may elect to ignore setting up the path to the mixer described in the following section.
Auxiliary Programs and Default Images:
Windows 3.1 users should tell the program where to find the sound cardÆs mixer program using the Options/ Programs/Default File Path menu item.
Click on "Programs/Default File Path" in the "Option" menu.
In the line labeled "Mixer Path" enter the COMPLETE path and command to start the sound cardÆs Windows mixer program.
Click "OK" to close this dialog box.
The "mixer lever" icon ( 7th item in the tool bar) will now be lit.
Click on the "Mixer" icon! If you have entered the correct command, the mixer will appear. If an error message appears, you have made an error in telling the program how to call the mixer. A typical entry could be C:\SB16\WINAPPL\CTMIXER.EXE and, while this is probably not the entry for your system, it illustrates the form of the entry. Consult your sound cardÆs manual to help locate the proper directory and mixer application command.
You will need to access the mixer to set the receive input levels and the transmit "volume" settings. This is normally a one-time operation and the settings are not critical. Since the sound card mixers take different forms depending on the manufacturer and model of the particular card, it will be necessary to study your sound cardÆs manual to find out how to change the output level settings and the recording level settings.
Windows 95 Sound Mixer:
A standardized sound card mixer is included as a part of Windows 95 and this makes things easier.
Double click on the "speaker" icon in the lower right corner of the screen.
The first mixer screen which appears controls the OUTPUT of the sound card. This will be the mixer used to set the transmit levels to your tranceiver.
Since you will be using the Line-In for your SSTV signals from the tranceiver, you should remove any check mark that is in the section under "Line_In". If this item is "Selected", the output of your tranceiver will play through to the line output and speakers during SSTV reception which complicates the use of VOX or a PTT circuit.
Gaining access to the mixer that controls the INPUT to the sound card is next.
Click on "Options" and then "Properties". The "Properties" box will show that "Playback" was selected. The "volume controls" checked should include "Volume Control" and "Line-In" as a minimum.
Now select "Recording". Make sure that "Recording Control" and "Line-In" are checked.
Click on "OK", and the "Recording Control" mixer will appear.
Make sure that "Line-In" selected. If you have a notebook computer with a built in microphone, make sure the "Microphone" is NOT selected or room noise will be superimposed on your SSTV signals resulting in poor pictures. The "Line-In" and "Recording" levels will be used in the next section to set the input signal level to the sound card from your tranceiver.
The above steps will be used in the following section if you are using Windows 95.
Sound Card Setup:
Basic Sampling Selection:
Select Signal Processing from the Options menu and set the Sample Frequency and Bits per Sample. If you have a 486/50 or faster computer set the frequency to 22050 otherwise use 11025. Unless limited by the sound card, set the bits to 16.
Adapters are available at Radio Shack to go from the 1/8 inch stereo phone jacks used on sound cards to RCA type plugs. If you are using the "stereo" feature to handle two transceivers, these adapters work well to separate the two input and output channels. Another adaptor available is a cable that has a 1/8 inch stereo phone jack at one end and branches into two male RCA plugs at the other.
WinPix Pro accesses your sound cardÆs A/D and D/A converters through Windows. If you are not sure of compatability or if you later experience difficulties, make sure your sound card is operating properly under Windows. A test for this is to record and play back a ".WAV" file using the Windows "recorder" software supplied with your sound card. You should be able to record the audio output of your tranceiver (any QSO) and play it back.
Setting the Receive Level:
Connect the transceiver audio output to your sound cardÆs input using the connection which provides an audio level independent of the volume control setting. Connect the sound cardÆs output to the appropriate auxiliary input of your transceiver. Additional circuitry may be needed to isolate or attenuate the output of the sound card if the tranceiverÆs input is quite sensitive. You may also wish to construct a detector circuit to activate the PTT line on your tranceiver. Suggested circuitry is included in the Manual. After you have connected the sound cardÆs inputs and outputs to your transceiver set the receive level as follows:
Select the Monitor mode of WinPix Pro by clicking on the blue "eye and keyhole" icon, using the Alt+M shortcut key, or selecting Monitor from the Action menu. If Video Scope On is checked, toggle this feature off to remove the "scope" image from the screen.
Select "Data In" and the dialog background should turn gray indicating the sound card is processing data. If your transceiver is sending audio to the card, "Input Level", "Max. Freq.", and "Min. Freq." will be displaying data.
Use the "Get Mixer" button to call your sound card mixer program and move this window to a screen location where you can see the WinPix Pro dialog box in the background. Windows 95 users should double click on speaker icon (get the Recording Control).
Use the "mixer" to adjust the Level to a value somewhere between 50 and 100 percent. If you have selected 16 BIT sound conversion, this is not that important. Values as low as 20 percent work quite well. It is best to use a SSTV signal for the adjustment since voice is too inconsistent in level.
Following the setting of the proper level, click on "Data In" again and the dialog box background color will go back to blue. At this time the Mixer will disappear into the background.
Setting the Transmit Level:
To set the transmit level make sure you are on a "dead" band and that the transceiver is into a dummy load. Then take the following steps:
Click on "Tone Out"! The dialog box will turn red and the progam will be sending out a continuous tone.
You can now recall the Mixer by clicking on "Get Mixer" or getting the "Mixer" from the task bar of Windows 95.
Make sure you are in the portion of the "Mixer" that controls sound cardÆs OUTPUT.
Put your transceiver into the transmit mode and adjust the output volume of the sound card using the appropriate mixer control to set the level you desire.
Take the tranceiver out of the transmit mode and stop the tone by clicking on "Cancel" in the "Monitor Signals" dialog box. This will also close out the dialog box.
In general sound card mixers have some means of storing the settings. DonÆt forget to save the settings you have made. If the sound card mixer stores the settings to a specific file, you will want to append that file name to the mixer auxiliary program call. Windows 95 automatically saves the settings in its Mixers.
Sample Rate Calibration:
The oscillator that controls the sound cardÆs timing is crystal controlled but the accuracy of these oscillators will not satisfy the needs of SSTV. WinPix Pro provides an automatic means for measuring the frequency error of the sound cardÆs oscillator. The program then uses this data to calibrate the "sweep times" in the software.
The automated method uses another SSTV stationÆs signal for calibration and you should not attempt to transmit a picture until after you have performed this calibration.
From the Action menu select Receive. Alternatively click on the "green ear" icon or use the short cut keyboard option of Alt - R.
The Receive Control dialog box will appear.
At the end of the line which says "AutoRestart" is a box that says either "Any", "Family", or "Mode". Set this to "Any" using the up/down spinner.
Click on SSTV Calibration AND Receive!
Wait for the start of a SSTV picture. The station you are receiving should have a good signal strength and you should have reasonable confidence in his timing calibration.
When the transmission starts, the program should automatically detect the VIS code, switch to the proper SSTV mode, and begin receiving a picture. An error in tuning, QRM, or DSP settings such as low frequency cut off or an automatic notch can block the VIS code. The selection of SSTV Calibration automatically sets the horizontal sync into a phase locked loop to track the incoming signal.
The picture should come down straight but may be offset a small amount to the right or left. This offset is the result of the program correcting for the error in the sound card clock and is a temporary condition.
When the picture is completed you will get another dialog box which will display the computed sound card error in parts per million.
If the received picture was straight and reasonably free of noise, tell the program to save the new correction.
Most sound cards will have a clock error less than plus or minus 200 parts per million. Some cards, however, can have considerably larger errors. The image quality will not be effected by a large error but, if you get a large number, you should repeat this calibration to make sure it is consistant. The answers should not differ by more than about 10 parts per million from one calibration to another. Numbers as high as 3000 parts per million have been seen but numbers higher than this should be suspect.
In the "Options" menu select Signal Processing.
The dialog box will show an item labeled "Present Sound Card Timing" will show the stored number.
If you decide to repeat the calibration but feel that the stored number is probably correct, DO NOT RESET the stored number to zero. If you want to start over, the number can be reset to zero.
While this dialog box is present you may want to select the preferred option for horizontal sync.
You will probably prefer either "No Sync ( All)" or "PLL - Robot Modes". The latter will allow all modes to free run with the exception of the Robot modes.
THE ON LINE HELP WILL PROVIDE CONSIDERABLE INFORMATION ON THE USE OF THE FEATURES IN THE PROGRAM. THE MANUAL WILL ALSO PROVIDE THIS INFORMATION PLUS MORE.
