“This is AF5NP calling K5ZFA”. If you heard this on a repeater, would it be OK? The answer is that it is legal but the call sign order is backwards and contrary to protocol.
You may hear a new ham (or a very distracted old timer) on the air identifying first, followed by their target station. That’s not right.
Well-established radio procedure is calling or identifying in a To-From sequence (call sign order). Whether answering a CQ, calling a station on a repeater, or simply identifying the two parties in a contact, the other station call sign is given first, followed by your own.
Using our example above, the proper protocol would be, “Calling K5ZFA, this is AF5NP”, or in its most minimal form, “K5ZFA, AF5NP”.
Note that the basic To-From protocol using just the two call signs satisfies requirements and is well understood on the air. K5ZFA would hear AF5NP calling and may return the call in the same manner (“AF5NP, K5ZFA”).
This to-from sequence is so ingrained that when the order is reversed other stations are likely to get confused; there is a risk of mistaking one station for the other.
Another reason for using this sequence is that it is normal and natural for a ham to alert on their own call sign. When it is given in the to-from way, they will tend to pay attention to what comes next, which should be the calling station’s call sign. Reversing this order means the called station is likely to miss the calling station’s ID because it was given first and they weren’t paying attention until they heard their own ID.
New hams should make this their practice and before long it will become second nature.