No Ubuntu 20.04 release file for PPA can not enable PPA without it
CQRLOG is an advanced ham radio logger based on MySQL database. Provides radio control based on hamlib libraries (currently support of 140+ radio types and models), DX cluster connection, HamQTH/QRZ callbook (XML access), a grayliner, internal QSL manager database support and a most accurate country resolution algorithm based on country tables developed by OK1RR. CQRLOG is intended for daily general logging of HF, CW & SSB contacts and strongly focused on easy operation and maintenance.
More info: https://launchpad.net/~ok2cqr/+archive/ubuntu/ppa
Press [ENTER] to continue or Ctrl-c to cancel adding it.
Hit:1 http://us.archive.ubuntu.com/ubuntu focal InRelease
Hit:2 http://us.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:3 http://us.archive.ubuntu.com/ubuntu focal-backports InRelease
Ign:4 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:5 https://repo.skype.com/deb stable InRelease
Hit:6 http://dl.google.com/linux/chrome/deb stable Release
Ign:7 http://ppa.launchpad.net/ok2cqr/ppa/ubuntu focal InRelease
Hit:8 http://archive.canonical.com/ubuntu bionic InRelease
Hit:9 http://security.ubuntu.com/ubuntu focal-security InRelease
Err:10 http://ppa.launchpad.net/ok2cqr/ppa/ubuntu focal Release
404 Not Found [IP: 188.8.131.52 80]
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/ok2cqr/ppa/ubuntu focal Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.