Why We Use the Phonetic Alphabet On the Air
Post date: May 4, 2014 3:07:46 PM
We have all played the game of "telephone" with children. We whisper something into someone's ear, who whispers it to the next person, and so on. By the time we get to the end of the group, the message that comes out is often completely unintelligible. It's a fun way to demonstrate how easily messages can be garbled beyond all recognition.
The National Traffic System manual's appendix Methods, Procedures, and Guidelines specifies that we are to use the phonetic alphabet (also known as "International Radiotelephony Spelling Alphabet") for handling messages by voice. In particular, MPG says,
- 184.108.40.206 Mandatory use of phonetics and spelling: "Amateur call sign letters; 'amateur call WHISKEY ONE ALPHA WHISKEY;'" and
- 220.127.116.11 Preamble voicing rules regarding the station of origin: "Say call sign with phonetics without the introducer."
Message number 1 from KD8TTE being relayed by voice would have its preamble read beginning as
Number 1 routine kilo delta 8 tango tango echo...
In the text and signature of the message, then, the way to read KD8TTE is,
Amateur call kilo delta 8 tango tango echo.
Because the National Traffic System is a public service to be used in times of emergency, it is imperative that we get the message right. Not only must the text be correct but details like the preamble and the signature must also be correct. A piece of traffic I handled May 1, 2014 demonstrates why.
COTN station KD8KBX took a piece of traffic for Columbus from Mason via a state-wide net. I took the traffic from 'KBX and confirmed that the check worked correctly, and that the station of origin and signature matched one another, showing a KD8 station. By all accounts, the message was correct. I delivered the message by phone to the recipient and originated a reply, which I brought back to the same session of COTN.
I looked up the KD8 station of origin and noted that the first name did not match the signature. I therefore originated my message, directing it to go to the name in the signature via the KD8 callsign in the station of origin and the signature of the message that generated the response I was handling.
The message ended up on the Tri-County Traffic Net, on the other side of the state. This certainly isn't unheard of; it might well be that the KD8 station has some other way to route the message to the real recipient, someone who might not be a radio operator at all. The TCTN station did not know the KD8 station named as the "via," and had to take some time to chase down a phone number. That in turn led to delivery of the reply to an inactive and now bewildered ham who doesn't even have a radio.
WB8QLT from the TCTN reached out to me and by searching the FCC ULS for matches by first name and city, we were able finally to determine what happened.
The station of origin was not actually a KD8 station but a KB8 station. Of course "D" and "B" sound almost identical when spoken, especially on SSB or AM. Of course even under poor operating conditions on SSB "delta" and "bravo" are almost impossible to mistake, especially twice: both preamble and signature!
As a result of the single error appearing twice in that message, the message I originated was delivered via NTS to the wrong local net and a delivery station had to do legwork to find a phone number to confuse an inactive ham by delivering a response to a message that he didn't even know to exist. I have since generated the correct message and will start that on its way (albeit three days later), and will be tracking down where the garbling took place with KD8KBX, who relayed the message to me.
The upshot here is that I had a lovely chat with WB8QLT that otherwise I wouldn't have had. And both TCTN and COTN will get a valuable lesson in the importance of getting the details right.