Is CANFI a free software?

Yes, it is. Starting with V2.7 the license is changed to GPL and the source code is published at GitHub. As CANFI is considered a derived work of the GPL-licensed rtlsdr.dll (basic DVB-T tuner control library) the licemse change is a mandantory
step to ensure a legal distribution of  the whole package.

There are many different types of DVB-T sticks. Which tuner chips are supported by CANFI?

CANFI basically supports E4000 tuner chips with native versions of rtlsdr.dll.
From V2.7 the more common R820Txx is also supported using a special version of rtlsdr.dll.

Most software comes with an installation procedure. Why CANFI does not have an installer?

The software is developed under Microsoft's .NET 4.0 platform with Visual C# 2010 Express and does not need an installation procedure. Furthermore, the Express
versions of Microsoft Visual Studio do not support installer projects.
An external solution is possible but not considered so far.

Can I run CANFI from inside the <Windows\Program Files> directory like other software?

Basically yes. But CANFI is writing files into its executable directory, which is not state-of-the art and not recommended by Microsft. This should work with Windows XP anyway. Under Windows Vista and later the UAC is blocking write access into
that directory.
To get it working, you must use the "Run as adminstrator" option. It is recommed to use another directory if possible.

I have selected the correct DVB-T stick in CANFI-Options but the main window is still showing an error message. Why?

If you change your DVB-T device initially, it sometimes happens that it is not recognised by CANFI. It seems to be a problem with the libraries. Close CANFI and restart it again.

I got strange behavoir while running CANFI with a RTL820 tuner chip. An error "Cannot set tuner stage gain xxx" is showing. What does this mean?

To work properly, CANFI needs a special version of rtlsdr.dll provided by DL8AAU.
This may cause a conflict with previous versions probably istalled along with other
software packages. Please check C:\WINDOWS\SYSTEM32 for older versions and remove them.

Please publish modules in offcanvas position.