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Author Topic: HF Frequency Question  (Read 7119 times)

Offline bcrosby

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HF Frequency Question
« on: May 08, 2006, 03:03:54 PM »
I've started listening to some of the HF feeds (especially the new caribbean one) and just have one question.

What is the two tone "pings" I hear every so often?



Offline Jason

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Re: HF Frequency Question
« Reply #1 on: May 08, 2006, 03:27:22 PM »
Quote from: bcrosby
I've started listening to some of the HF feeds (especially the new caribbean one) and just have one question.

What is the two tone "pings" I hear every so often?


Those are SELCAL tones and allow aircraft to be "called" back on frequency when the HF controller needs to speak to that aircraft.  SELCAL allows pilots to turn down the HF frequency volume (because it would be pretty annoying to listen to static the whole time!) but can still be reached.

SELCAL consists of 2, 1 second tones that corrispond with 2 sets of 2 digits (letters) of the alphabet.  Aircraft have SELCAL codes (eg: DJ-RS) which the controller uses to send the SELCAL to that aircraft.  If you run a quick google search on "SELCAL" you will be amazed at what you will find (and learn!).  A SELCAL also activates a visual light/button for the pilot(s) to see.

I have all 121 of the tones in digital format (.wav to be specific) and I can send them to you if you'd like.  E-mail/PM if you're interested.

Hope this helps,
Jason

P.S. Also note that SELCALon VHF is available, but rarely used (...at least here in the US).

Offline bcrosby

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HF Frequency Question
« Reply #2 on: May 08, 2006, 04:16:55 PM »
Ahh makes perfect sense. Thanks for the info!

Offline Rob K

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Re: HF Frequency Question
« Reply #3 on: May 30, 2006, 06:15:40 PM »
If I may say so, you may find my selcal site of particular interest to you.

www.selcalweb.co.uk

Any other selcal questions/queries, please do ask.

Rob K

Offline Jason

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Re: HF Frequency Question
« Reply #4 on: May 30, 2006, 06:36:14 PM »
If I may say so, you may find my selcal site of particular interest to you.

www.selcalweb.co.uk

Any other selcal questions/queries, please do ask.

Rob K

Wow, great site, Rob!  I found it very interesting... Thanks for creating and maintaing the site.  :-)

Regards,
Jason