GNC 255 Radio - Automatic Decoding

[CC268]

Reading through the Pilot's Handbook for the GNC 255, it states, "Besides traditional NAV/COM features, the GNC 255 also incorporates workload-reducing functions such as automatic decoding of the Morse code station identifier for VOR/LOC".

What does this mean?

I can't seem to find anything else in the manual as to what this really means, but maybe I am just missing it.

 

[baboss]

Automatic display of station ID by decoding Morse code
For example, flying around here I put in 108.20 for the BMI VOR. It decodes the MORSE ID and displays BMI on the radio

 

[denverpilot]

Reading through the Pilot's Handbook for the GNC 255, it states, "Besides traditional NAV/COM features, the GNC 255 also incorporates workload-reducing functions such as automatic decoding of the Morse code station identifier for VOR/LOC".

What does this mean?

I can't seem to find anything else in the manual as to what this really means, but maybe I am just missing it.

On most of the Garmin panel mounts listen to the Morse transmitted by the Nav station and decode it and display it, supposedly eliminating the need for the pilot to tune and IDENTIFY the station.

What I’ve never seen is an example of what the Garmin does when the station stops transmitting an ID, AFTER it has identified the station, which is the methodology FAA uses when a station fails and doesn’t pass its own self-tests.

Sometimes when a VOR or other Navaid is undergoing maintenance they’ll transmit “TEST” in Morse or a continuous series of dashes. I also haven’t seen what the Garmin unit do under these instances when the pilot may have missed an out of service NOTAM pre-flight or the station maintenance started without NOTAM’ed warning while they were enroute.

I would suspect they’ll decode “TEST” just fine and wouldn’t alert on it in any way other than to display it, which would be a big hint to the pilot they’re not flying a useable nav signal. No idea what they’d do with continuous dashes other than to refuse to ID that station. Both would likely be VERY subtle in a busy cockpit.

 

[CC268]

Ahh gotcha. So it eliminates the need to listen to the morse code...assuming it displays the ID.

 

[Jeff Oslick]

Our SL-30 has this feature. It is nice. I don't see the risk of a change to a test ID as being any bigger a risk with these radios that with auditory decoding. How many of you would continuously listen to the ID code throughout the entire approach? I can say I never did.

I would suspect they’ll decode “TEST” just fine and wouldn’t alert on it in any way other than to display it, which would be a big hint to the pilot they’re not flying a useable nav signal. No idea what they’d do with continuous dashes other than to refuse to ID that station. Both would likely be VERY subtle in a busy cockpit.

 

[denverpilot]

Our SL-30 has this feature. It is nice. I don't see the risk of a change to a test ID as being any bigger a risk with these radios that with auditory decoding. How many of you would continuously listen to the ID code throughout the entire approach? I can say I never did.

I did on ADF. But that’s a whole different thing.

I also used to accidentally leave the ident on from the VOR/LOC/DME (how many people ident their DME properly? Heh...) and drive @jesse nuts because a) I was overloaded, and b) I copy Morse anyway so it doesn’t bother me.

Or more accurately, it’s common for me to have Morse coming out of a radio in the ham shack in the background anyway, so I literally can tune it out when busy and not even realize it’s there. A loss of the pattern or a change to “TEST” or dashes would be noticed though.

It’d be like someone in the room was talking a few feet away but you’re not really listening to them, and then they stutter or just start saying “TEST TEST TEST” over and over. Haha.

But anyway I know what you mean. I’m just curious what the Garmin does but I haven’t been able to convince FAA to take a VOR out of service or have one fail at a convenient time for me to test my Garmin. Hahahaha. I guess if the Skylane had hard points and a HARM missile...

 

[AggieMike88]

The CX80 in our Skylane has this feature and it is also very useful.

 

[Axtel4]

I would frustrate my CFII when I would tuned to a nav aid, decoded and announced the station ID / status, switched off the audio, and returned to other duties before he could look down at the chart / plate and decode the dots and dashes. My frustration was the station ID wasn't at some reasonable speed like 15 - 18 wpm so I would not have to switch from decoding CW as character groupings to decoding it character-by-character at the much slower speed.

 

[Ryan F.]

My GTN650 does it... it's a very nice feature.

Modern avionics are slowly drumming the busy work out of instrument flying.

 

[denverpilot]

I would frustrate my CFII when I would tuned to a nav aid, decoded and announced the station ID / status, switched off the audio, and returned to other duties before he could look down at the chart / plate and decode the dots and dashes. My frustration was the station ID wasn't at some reasonable speed like 15 - 18 wpm so I would not have to switch from decoding CW as character groupings to decoding it character-by-character at the much slower speed.

Agree. It’s too damn slow. LOL.