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4 Answers

Marker Beacon SENS need to be on LOW why? what is the HI for?

Asked by: 6405 views Instrument Rating

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4 Answers

  1. Lucas on Jun 28, 2012

    High setting was for use when fan markers were used along airways to mark one’s progress along the airway ie pre-DME.Hi setting (high sensitivity) was used to allow for the resulting weaker signal cruise altitude caused.

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  2. Matthew Waugh on Jun 28, 2012

    Another use – and Lord knows I’m not saying this is a good idea, I’m just saying I’ve seen it taught – is to put it on HI sensitivty at the start of the approach and, when you hear the beacon coming in, put it on LO sensitivity so it doesn’t blow your ears out as you cross the beacon. It gives you more warning that you are approaching the beacon.
    Of course the marker beacon is fast becoming a thing of the past – so we look forward to future questions such as “I never use this HI LO switch on my panel, what does it do?”

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  3. Steve Brack on Jun 29, 2012

    The “high” sensitivity setting was for use with the fan markers that were used along airways to mark one’s progress before the widespread deployment of DME, particularly when radio range stations were still being used to define the airways.  It compensated for the weaker signal resulting from being at cruise altitude and thus farther away from the marker beacon.  Fan markers are still used along airways to some extent overseas, I understand.
    The “low” sensitivity setting is for use with marker beacons because if receiver sensitivity isn’t reduced, the beacon could be picked up at 2-3 miles away, making the signal useless for precisely locating yourself along the approach path.

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  4. Will on Aug 02, 2013

    LO/HI is a sensitivity adjustment
    Selecting “LO” switches an attenuator into the input line of the receiver. This is normally done below 10000ft.

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