TransOceanic monitoring question


#1

Hello all, pardon the newbie question but …

I have been monitoring the High Frequency transoceanic position reports, etc. between enroute aircraft and what I presume is New York Center. I will catch the flight number and then pull the flight up on the map. I’m one of those hams who listen 100X more than I ever transmit so it’s been enjoyable.

My question is this, what are the two tones that the center transmits after the flight checks in? Sounds to me more like an old two tone Plectron rather than a data burst or anything.

Any help?

Thanks,
Alan


#2

Sounds like it might be the notification tones for Selcal.


#3

That must be it. It makes sense. Thank you!


#4

It sounds like selcal to me too.
We had a trip across the Atlantic a few years ago, when we checked in with the first oceanic controller who does a selcal check and takes your first position report we found the selcal decoder had decided to take a vacation. Since I was in the right seat on that leg I got to listen to the HF all the way across. I thought my ears were going to bleed before we got to the other side.

W4WAF You could be listening to New York radio (not NY center), but could also be receiving Gander or San Juan and on a good day Shanwick. These days fewer and fewer aircraft use HF for the primary communications across the water. Data Link is quickly replacing HF as the preferred means of communicating position reports and other operational messages.

John