Marker Beacon Tones

"Jeff P" wrote in message om...
Where do marker beacon tones come from? Are they generated in the
receiver or are they transmitted from the ground station. I ask
because sometimes I see my lights blinking, but I don't hear a tone.
(yes, I do have the receiver selected on the audio panel) Is this a
problem with the marker receiver / audio panel?

The marker beacon transmitter works by transimitting one of three audio
tones (400 Hz for the outer, 1300 for the middle, 3000 for the inner) on
75MHz. This is how it knows which light to light. Most receivers work
by just running the audio through filters for each of these frequencies and
using that to light the appropriate light. They also pass the audio to the
audio panel (without any regeneration, usually just some limiting). If
the right light comes on, but their is no sound, the problem is in your set,
probably between the reciever and the audio panel.

What kind of audio panel do you have?

"Jeff P" wrote in message
om...
Where do marker beacon tones come from? Are they generated in the
receiver or are they transmitted from the ground station. I ask
because sometimes I see my lights blinking, but I don't hear a tone.
(yes, I do have the receiver selected on the audio panel) Is this a
problem with the marker receiver / audio panel?