I noticed when I am calling cq that some folks have their soundcard and software not set right.
I can hear the bell to alert someone is calling CQ.
if you are in front of your radio.. and not sending out a beacon.. and see your radio xmit, might
check out your settings.
I have also had qso's with guys I can hear the bell's.. I try to let them know when I work them.
Murf
n7uvh
I have listened several times the same bell coming from radio speaker after the end of CQ, never understood what it really is