Ive got a Narco splitter that lets me select between my main and secondary comm and nav radios, the unit itself has 3 separate LEDs that are labeled O, M, and I. Today the O light flickered while I was XC over central pensylvania. What do these LEDs indicate?
Narco radio splitter question
- Thread starter Pilot71R
- Start date
Marker beacon indicator. I is the inner marker, O isnthe outer marker and M is the middle marker. Each is a different color. Only used for instrument arrivals. Not sure how many working systems are left.
Tons of instrument approaches still have marker beacons on them. While the FAA has deemphasized their importance (used to be that the DH went up when it MM was out) they are still technically part of the instrument landing system.
These are 75MHz transmitters that pretty much shoot straight upwards, so that when you're tracking the localizer inbound you know when you get to certain points. The OM roughly corresponds to where you should be intercepting the glidepath on most approaches. THe MM close to where you'll reach the decision height, the IM found very close to the runway only on approaches where they have special lower DHs for the airliners.
The signal is modulated with different frequency tones and pulsing pattern. The OM is LONG-LONG, the MM LONG-SHORT, and the IM SHORT-SHORT. The difference in the tone allows your marker receiver to light up the appropriate I-M-O light.
The thing with the switches on it is commonly called the AUDIO PANEL.
It's not uncommon to have the thing go off when you're arriving or departing or flying over the approach end of an airport.
There are also FAN MARKERS which are the same thing stuck out in the middle of an airway. Those by and large have gone away.
Here's a picture of what the transmitter looks like...you've may have flown over/driven by one without realizing what i was..
Tons of instrument approaches still have marker beacons on them. While the FAA has deemphasized their importance (used to be that the DH went up when it MM was out) they are still technically part of the instrument landing system.
These are 75MHz transmitters that pretty much shoot straight upwards, so that when you're tracking the localizer inbound you know when you get to certain points. The OM roughly corresponds to where you should be intercepting the glidepath on most approaches. THe MM close to where you'll reach the decision height, the IM found very close to the runway only on approaches where they have special lower DHs for the airliners.
The signal is modulated with different frequency tones and pulsing pattern. The OM is LONG-LONG, the MM LONG-SHORT, and the IM SHORT-SHORT. The difference in the tone allows your marker receiver to light up the appropriate I-M-O light.
The thing with the switches on it is commonly called the AUDIO PANEL.
It's not uncommon to have the thing go off when you're arriving or departing or flying over the approach end of an airport.
There are also FAN MARKERS which are the same thing stuck out in the middle of an airway. Those by and large have gone away.
Here's a picture of what the transmitter looks like...you've may have flown over/driven by one without realizing what i was..
Much better description than mine, thanks! As for the 'splitter', before I replaced the Narco radios many years ado, I had what I called the Radio Shack A-B switch. That's really what it looked like, too.
