Selcal Success
 

HF is a fact of life for our field of operations. Selcal checks come good sometimes, and other times no joy. Some blokes request ATC to "send a longer signal" after a failed Selcal check. Viola! This seems to work. Any clues as to why, and does this actual phrase have any valid meaning to those working in ATC?

Haven't come across "longer signal" before. Can't on our equipment, duration of tones preset. Our guys just push a button. I have heard operators send a series of tones and get a response. Don't know if it helped.

Do ATC anywhere directly use HF/SELCAL? Done by FSO's (whats left of them) here.

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I am not an animal, I am an ATC.

HF SELCAL is used on the North Atlantic for most of the traffic. Though with datalink and FANS, the number using it should slowly decrease.

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10 West
UK ATC'er
[email protected]

Mango 3, a double pulse works sometimes. The system relies on a Heath-Robinson designed system of vibrating reeds which resonate in sympathy with a coded tone. The fist pulsed tone gets the reeds vibrating, the second makes them vibrate that bit more and hopefully enough to trigger the alert.

This was covered by a recent thread in much detail.

REEDS???

You are joking surely. Tones have been generated electronically here since early '80s.

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"Station calling Centre, grow a head..."