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Author Topic: HF over the Atlantic  (Read 6500 times)
neilalp
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« on: December 12, 2004, 10:29:13 PM »

I enjoy listening to the HF atlantic feed in the evening, but had a few questions.

*Every so often I hear some tons and just wondered what those ment.  Are they the ARCARS data?

*Also I hear both Gander and Shanwick people talking.  Does the antenna being used pick up everything over the Atlantic?

*Why are the longitude and latitude numbers given out? Is it for possition?  With GPS and today's technology we still have to use this form?

So if someone could explain some of the communications that'd be great.
Thanks
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Jason
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« Reply #1 on: December 13, 2004, 09:29:59 AM »

HF radio operators for the Atlantic do not have radar, so aircraft have to give position reports in long/lat form from their FMS/FMC.  I'll get back to you on the other questions.  I'll be asking my dad, who is a Citation XLS captain.  He uses HF often.

Jason H.
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FWA2500
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« Reply #2 on: December 13, 2004, 09:04:05 PM »

comunications......what all do you want to know? im a pilot for Freeworld Airways (virtual airline) so i should be able to help as everytime i fly, its online with VATC....


initial contact:
"good day,<call sign> with you FLxxx (or if on aproach, say nearest VOR), i have (information, eg: alpha)"

not sure all that atc says...lol, to busy in th cockpit setting up for the flight...ive recorded some of my online ATC comunications, if i can find a place to host them, ill link them to you guys here Smiley
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neilalp
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« Reply #3 on: December 13, 2004, 10:02:37 PM »

FWA,

I now the basic ATC communications, but I'm talking about HF over the Atlantic stuff.  It is slightly different than "over land stuff".  There is a lot of positioning and time reports to cross 40W, 30W, etc.  Plus there are many tones that you normally don't hear.  

Thanks for trying to help out!
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dave
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« Reply #4 on: December 13, 2004, 10:19:45 PM »

Quote from: neilalp
FWA,

I now the basic ATC communications, but I'm talking about HF over the Atlantic stuff.  It is slightly different than "over land stuff".  There is a lot of positioning and time reports to cross 40W, 30W, etc.  Plus there are many tones that you normally don't hear.  

Thanks for trying to help out!


Those tones are SELCAL tones.  SELCAL is a system that allows the pilots to not have to listen to HF static/noise throughout the flight, but allows ATC to call the pilots when they need to.  When the SELCAL tones are received, the receiver squelch (or whatever else silences it) opens up.

http://www.arinc.com/frequency_management/selcal/selcal_ops.html


-dave
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FWA2500
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« Reply #5 on: December 13, 2004, 11:06:32 PM »

anytime Smiley


btw, im new at listening....lol...im used to being in it...... rolleyes
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JetScan1
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« Reply #6 on: December 14, 2004, 08:45:31 AM »

neilalp,

Traffic across the north atlantic will fly on organized tracks, called NAT Tracks. These tracks change daily and are generated by Gander or Shanwick to take into account the upper winds to give the fastest route. When flying on these tracks it's required to send a position report passing every 10 degrees of longitude, 50W, 40W, 30W, 20W. As there is no radar coverage available these position reports are used by ATC to maintain separation between aircraft, which is a minimum of 10 minutes in trail at the same altitude.

More and more aircraft are being equiped with CPDLC, which is a datalink system that sends position reports automatically. While CPDLC equiped aircraft are not required to send position reports on HF voice frequencies they still call up for a SELCAL check and will use HF voice as a backup if required.

You can access the daily NAT Tracks from this site:

https://www.notams.jcs.mil/common/nat.html

Some information about north atlantic ops at this site:

http://myweb.tiscali.co.uk/montecarlo/atlantic/

And some information about CPDLC at this site:

http://www.aviationmanuals.com/articles/article4.html

DJ
« Last Edit: April 09, 2007, 10:48:38 PM by JetScan1 » Logged
neilalp
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« Reply #7 on: December 14, 2004, 09:15:25 AM »

JetScan1,

Thanks, I've started to read some of those websites and it is becoming clearer and helps with your summary post.  This is all very interesting as I've flown over the atlantic many times, but never realised this happend.

Thanks!
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767intlpilot
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« Reply #8 on: April 02, 2007, 07:49:04 AM »

I don't mind replying, I know a little about the subject.

We still use this form for those of us, like on a Boeing 767 that do not have GPS.  There are a few airlines out there crossing the pond that do not use this advanced tech.  As far as the lat/long, yes these are position reports, latitude being the first position heard followed by longitude.  The position goes either to Gander, Shanwick, Santa Maria in the Azores, or Iceland radio, all depending on route of flight and position of the tracks across the pond.

Gander and Shanwick share many of the same freqs, which is the reason you hear both.  Many times we cannot get one or the other on a given freq, so have to go to alternate freq.

Hope this clears up some questions.

Dan.
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767intlpilot
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« Reply #9 on: April 05, 2007, 09:36:50 PM »

So you need some "over the pond" info?  I think I can help!  I'm a pilot for a major US carrier and I fly across the pond all the time.  Email me and we'll chat through the emails.  Position reports are made every ten degrees of longitude change, and the reports are given Latitude first followed by longitude and the time that fix was crossed at in GMT.  Next is altitude, followed by an estimate for the next position and then the next one after that.  The last NUMBER you'll hear is fuel on board either in pounds or tons depending on the air carrier.  Last is the SELCAL code.  (selective calling)

Hope this clarifys some of your questions.  Happy to talk and share more info any time.  Email me and I'll give you a cell phone contact.

Regards,

Dan.
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m50
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« Reply #10 on: April 06, 2007, 04:15:49 PM »

with the the increasing use of datalink over the ocean it is obvious that the days of HF voice comminucation over the Atlantic are numbered....pity
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