5.5492?

[btlacer]

Every evening I tune my Radio Shack Dx-394 tp 5.5492 USB. It kinda sounds like air traffic controlers. They will talk for a while and then there are two steady tones that sound off. Not sure why there would be tones on air traffic controlers? Anyone know what this is I am listening to? I usually can't pick it up till sunset central time and can hear it for several hours after sunset. Thanks for all the help to come.....


Beau Lacer

RS Pro-197
RS DX-394
Yaseu FT-2800

[brandon]

Hello. You are hearing transoceanic flights operating on Major World Air Route Area (MWARA) frequencies . The frequency is actually 5550 KHz, that's New York Radio, for flights in the Caribbean area A.

See the Wiki and these other sites for many other frequencies in use.
North Atlantic, Caribbean - The RadioReference Wiki
Pacific, Asia - The RadioReference Wiki
MWARA - HF Underground

The busiest Atlantic freqs during the overnight hours are usually 5598, 5616, 5649 for European bound flights.

[majoco]

Might have been a finger slip while you typed the frequency but most 5Mhz band aeronautical HF frequencies are around 5.5xxMHz - the two tones (4 actually) are the 'selcal' tones.

The control centre will pick the most suitable frequencies for primary and secondary use, so the 5.5Mhz frequency probably is assigned as 'primary' in the evening, an 8 or 3 Mhz freq may be the secondary

Brandon beat me to it! He obviously has a better local knowledge!

[brandon]

I forgot to add, the tones you hear are SELCAL tones. The ground station uses them to alert the airliner when they need to communicate with them, so the crew doesn't have to listen to HF static for 7 hours. Here is good article that explains in further detail: SELCAL - Wikipedia, the free encyclopedia

[btlacer]

Hey guys thanks alot for the info. that info sounds about right. The reason I typed the frequency the way I did is because that is the frequency that I pick this up clearer and can understand the control voice better....