/notice +#channel messageHERE
Simple aliases can be made for messages like this. As an example, here's a /vn alias (voice notice):
vn notice + $+ $chan [Voices] $1-
If you add this to the Aliases section (ALT+D) on a new line, you can just type /vn messageHERE to send a voice notice. The [Voices] bit is just for decoratio so it sends the text '[Voices] <your message>' to the voices. It can be removed or edited to your liking.
Usually, /onotice can only be done if you are opped. With /notice you do not need to be opped. You can also do /notice @#channel for the channel ops, and /notice @+#channel for the voice AND ops.
Regards,
