Then again...

[them...@btinternet.com]

I uninstalled the first attempt and downloaded an AppImage file called Gqrx-2.6-1.glibc2.17-x86_64. This is a new file type to me, so after some googling, I made it executable by using the

Linux chmod a+x command, and to my pleasant surprise, I now seem to have a working system!!!!

 Now to try a usb stick or two.
A big thankyou to Alexandru Csete OZ9AEC.

THANK YOU.