Getting Started with Fldigi – Including Flmsg and Flwrap


Start Flwrap.

Click the Compress button (see notes below).


  • The Compress button switches Flwrap from plaintext mode to base64 encoding ( Base64 is a textual representation of data. Any file type can be converted to base64.
    The word Compress is somewhat misleading. ASCII text files converted to base64 generate smaller WRAP files. In contrast, binary files (images, Word documents) generate larger WRAP files compared to the original file size.
    As noted, any file can be converted to base64. However, it is imperative to click the Compress button if file is NOT an ASCII plain text file. Failure to do so will result in a failed checksum after the WRAP file is transmitted.

Drag and drop the source file into the Flwrap box labeled “Drop file here.”

When Flwrap shows “success,” the file has been converted to the WRAP format.


  • The resulting WRAP file will always be placed in the same directory as the source file.

Open Fldigi if it is not already.

Right-click in the turquoise transmit pane.

Click Insert file.

Navigate to the location of the flwrap file.

At the end of filename, select All Files.

Double-click the flwap file (with the .wrap extension).

In the transmit pane you will see a bunch of random letters, numbers, and symbols. This is the base64 encoding of the WRAP file.

Click Rx|| .

Click T/R ( or ).

The WRAP file will be transmitted and Fldigi will switch back to receive mode.

All information in the “Transmitting – Fldigi” section applies.


  • Using the net standard MT63-2KL, a 2.3KB WRAP file takes just over 2 minutes to transmit. Testing indicates about 1 minute transmit time is needed for every 1KB of file size. For the FM repeater net, the WRAP file size needs to be less than 2.5KB. File size can be determined in the Windows File Properties dialog box. Flwap will also display the WRAP file size in the line “out= x bytes.” Example shown: “out = 2325 bytes” -> 2.3KB.