What is this annunciator panel do?

[Jeff Johnson]

Any idea what this is for
It's sitting below my traffic switch but I can not for the life of me find out what this is...

[donv]

Marker beacons. I don't remember what "A" was, but "O" is Outer and "M" is Middle. They light up when you fly over the beacon, and they also make a beeping tone.

[Jeff Johnson]

What is the HLT sens switch do?

Is this its own component or is it connected to something else

And thanks so much

Jeff

[Jeff Johnson]

I googled it and found the info

Thanks

[donv]

Is it some sort of sensitivity? Or the volume for the audio signal?

[SKYFLYER]

The "HLT" switch was for HIGH, LOW and TEST was for the three lights. As I recall this king unit was before the advent of CAT I and CAT II requiring the inner marker so the "A" would illuminate when intercepting the approach or glide slope and the "O" was then outer and "M" middle  markers respectively along with the audible signal. The "SENS" switch moved to the up position (H) was high sensing or a "band 5500 feet (2500 from and 2500 to the beacon). When in "L" (low) or middle position the distance was basically cut in half. The beacon transmitted in a "V" or fan broadcast within the boundaries of the glideslope. so when high sensing some beacons would overlap thus the reason for the low sens as well as more accurate marker location. At least that is what I seem to recall from 40 years ago. I have not seen one of the old King units in a very long time.

[Jeff Johnson]

Is it useless?

Old shit sometimes has its usefulness

Just like our planes !!!

[JimC]

Not at all useless. I believe it's legally required to fly an ILS. My brand-spanking new fancy G500/GTN750 panel has that capability - the lights, speaker and HLT switch are integrated into the GTN750.

[donv]

I didn't know the GTN750 (technically the GMA-35 audio panel) has a marker beacon receiver! I guess I should turn mine on.

[JimC]

On mine, it's just to the right of the frequency boxes - it replaces the words "Audio Panel" when a beacon is received. I leave the audio on, and every now and then I get a tone flying over a marker. A quick tap mutes it.

[donv]

Learn something new every day!

[Jeff Johnson]

Now I know!

Been doing my IFR training around the west coast and yep if I turn the audio marker audio on I get to hear when I'm crossing the markers. 

Drives my instructor nuts... but at least it keeps him awake

[SKYFLYER]

See you found a use after all.... and a very good thing to keep one's instructor alert

[Jeff Johnson]

I'm enjoying it immensely:)

And the fact I get to fly in the clouds too

[Maurice Gunderson]

If I remember correctly the “A” stands for “Airway.”

I also leave the marker receiver on and it beeps when I fly over one. I haven’t encountered an “A” in at least 20 years.

Here’s what Wikipedia says:

https://en.m.wikipedia.org/wiki/Marker_beacon