If any program would be capable of converting .sm3 files to .sm4 files, it would be XPMPro spectrum analysis software. Except for this, have no information about any other 3rd party software capable of handling RHK Technology formats.
Convert RHK Technology proprietary file format to RHK Technology proprietary file format.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert sm3 to sm4 on Windows
A spectrum analyzer for Windows.
Convert from sm3 file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.