Questions and answers

Here some problem descriptions and possible solutions that might be needful:

Problem:
When I am receiving pictures with JVComm32, they always get out of synchronization, showing a kind of "steps"
If you are running JVComm32 on a notebook computer, or another computer that is equipped with WLAN, please deactivate the WLAN card. More recent Notebooks do frequently have a case switch for deactivating WLAN. Otherwise, you can deactivate WLAN in the device manager.

Problem:
The above solution proposal did not help.
Another possible solution:
Please try the following: With the right mouse button, click on the "My computer" icon on the desktop. Then, click on the "properties" item of the popup menu. A window that is labelled "System properties" appears.
In that window, select the "Performance" tab sheet and click on the "Graphics" button in the “Advanced settings” area. A new window appears with a slider control that is labelled "hardware acceleration". Move that slider to the leftmost position, or to the leftmost but one position. Then, close all windows and restart you computer.
 

Problem:
I have made the above setting but still, when I am receiving pictures, JVComm32 loses synchronization each time I open another application, or if the RX picture display is scrolled. Eventually, it loses synchronization without any known reason. How can I avoid this?
Possible solution:
Probably, the overall performance of your computer is too bad. This might not be due to a lack in processor speed but quite often is because of a bad (or rather old) graphics card. If the problem only occurs when the RX window is being scrolled, you can easily fix this by selecting a zoom factor that makes the entire picture 'fit' into the RX window. Avoid using old 16 bit applications when JVComm32 is running. These applications are not very co-operative with respect to multitasking and can prevent JVComm32 from accessing the input data quickly enough. If JVComm32 loses synchronization without any recognizable reason, check if some 'power saving features' are enabled in your computer's BIOS. If yes, disable these features. A lack of RAM memory in conjunction with a slow hard disk drive (-- lots of time consuming swapping between RAM and virtual memory) can also be a reason for a loss of synchronization when other applications are active besides JVComm32.
 

Problem:
Why does the slant change during reception, e.g. if I move another window over the RX window?
Possible solution:
This is most probably a graphics driver problem. Especially some Matrox cards/drives seem to be prone to this problem. If you're facing this problem, try to change the colour resolution. When you're running in 24 bit mode, tray to change to 32 bit mode or vice versa, or try to change to a Hi-colour mode with 65537 or 32768 colours. In most cases this will fix the problem. If your graphics card driver offers an option 'bitmap caching', or something named similarly, try to disable it. This might help as well. It looks that some Direct-X drivers that come along with some graphics cards can produce slant problems as well. If the above suggestions don't fix the problem, try to de-install Direct-X and look if the problem is gone. If it's gone, try to install a more recent version of Direct-X.
 

Problem:
I want to use JVComm32 in conjunction with the Windows 98 scheduler but the 'Do you really want to quit' query prevents JVComm32 from being shut down automatically.
Possible solution:
Make sure the check box "Close query at program end" on the "Misc" tab sheet of the JVComm32 configuration window is not check-marked.
 

Problem:
When I'm receiving short wave fax stations, the charts transmitted by some of these stations are not phased properly. E.g. the left edge of the chart is in the mid of the screen. How can I fix this?
Possible solution:
Some fax station transmit a phasing signal that is different from the standard 95% black - 5% white signal. Sometimes, a 50% black - 50% white signal is transmitted instead. To make JVComm32 phase correctly to these stations, go to the fax mode editor and change the phasing mode for the hf-fax mode from 'normal' to inverted. You can create a new mode in the fax mode editor, too, with all the settings being equal to the hf-fax mode with the exception of the phasing mode setting. Then, you can quickly change to this mode without having to go to the configuration window.
 

Problem:
Why do I get an 'exe file corrupted' or 'bad crc' error when I try to install JVComm32 on my computer?
Possible solution:
Not necessarily, but most probably there's a virus on your computer trying to modify the JVComm32 setup file. Use a virus checker to see if your computer is 'clean'.
 

Problem:
I can't run JVComm32 any more. If I try, I get a 'bad crc', 'exe file is corrupted' or similar error. What's the reason for this?
Possible solution:
As above, there's most probably a virus on your computer that has infected the JVComm32.exe file. JVComm32 has a built-in integrity check that normally detects all alterations that are done to the .exe file. Use a virus checker to find out if your computer is infected.
 

Problem:
When I'm running JVComm32 on my computer, it generates a lot of radio noise that interferes with the weak signals I want to receive.
Possible solution:
There's no specific answer to this problem. Just some suggestions:
Check if the noise is being reduced when you disconnect the audio line between your sound card and your receiver. If yes, try to insert an insulation audio transformer. (There should be no ground connection between the receiver and the computer.
If you're running JVComm32 with a sound card, and you don't need a Com port for RX/TX switching, set the Com port to 'none' in the configuration window.
Use ferrite cores on all lines that go to or come from your computer.
Keep your antenna as far as possible away from your computer.
These are only a few suggestions that are not guaranteed to help in your specific case...

Problem:
The “Denoise” function does not work efficiently on received FAX or SSTV pictures.
Possible solution:
This function can only give good results if it used on loss-free saved pictures. Please do not save your pictures in JPG format if you want to use this function.