Questions and answers
some problem descriptions and possible solutions that might be needful:
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.
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.
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?
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.
Why does the slant change during reception, e.g. if I move another
window over the RX window?
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.
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
Make sure the check box "Close query at program end" on the "Misc" tab
sheet of the JVComm32 configuration window is not check-marked.
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?
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
Why do I get an 'exe file corrupted' or 'bad crc' error when I try to
install JVComm32 on my computer?
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'.
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?
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.
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.
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
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
The “Denoise” function does not work efficiently on received FAX or SSTV
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.