Home › Forums › General Discussion › Flaring of synchronous satellites from Kelling Heath › Attachments.
There are (at least) two ways round the text file attachment issue. The obvious is to put your text into a doc/docx/pptx file. The recipient can then convert it back to text with a simple cut and paste.
The other is to rename the file because the uploader works on the extension not the contents. See here for an example.