An Op Note is an instruction for the delivering amateur radio operator. It typically details a condition regarding how to deliver the message (such as only on weekdays), or how to send a reply back. Op notes are optional, and do not count towards the check in the radiogram header.
There are two locations an op note can appear: after the address, and after the signature.
Address op note
After the address, and before the text, op notes placed here are generally related to handing or delivery. For example, the following address has an op note related to delivering by telephone.
JANE DOE AR1T
123 AMATEUR WAY
SOMETOWN WI 00121
PHONE NUMBER 330 555 4424 OP NOTE WEEKDAY ONLY
When the radiogram is read over the air, this phone number would be said as, “PHONE FIGURES THREE THREE ZERO. FIVE FIVE FIVE. FOUR FOUR TWO FOUR. OP NOTE WEEKDAY ONLY.”
Signature op note
Similarly, after the signature, an op note may be given related to replies or service messages (such as informing delivery was unsuccessful). Again, these do not count towards the check in the radiogram header. For example, if replies or service messages should be sent to a different amateur radio operator, the signature could appear as:
JANE AR1T OP NOTE SERVICE OR REPLY VIA AARON K8AMH DALLAS TEXAS
You would say this op note in the same manner as the op note after the address.