Navaid ID question.

fiveoboy01

fiveoboy01

Pattern Altitude
Joined
Apr 21, 2013
Messages
2,321
Location
Madison, WI
Display Name
Display name:
Dirty B
When you tune a VOR-DME, do you identify them separately even though the frequencies are the same?

I know that the(higher pitched) coded identifer sounding every 30 seconds means that only the DME is operative, but I'm not sure if hearing the VOR portion means they are both operative.
 
That's a good question.
Sorry, I do not have the answer as I have never owned/flown an airplane with a DME. But I am curious about the correct answer.
Btw, DME does not work on same frequency as the VOR. VOR's are around 100MHz (as you already know) and DME works around the 1GHz range. But majority of DME devices are coupled to the VOR frequency and tune the correct one internally. (there is a translation table but I couldn't find anything better than this one: https://www.yumpu.com/en/image/facebook/28252715/2 )
 
I learned something so thought it worth sharing. Glad you thought it was worthwhile.
 
Thanks for the article. Very helpful! Very interesting that while you tune the same "number" into your nav radio and DME, they are actually different.

My question kind of stemmed from the fact that my audio panel has 4 buttons for identifying navaids: NAV1, NAV2, DME, and ADF(I don't have an ADF in the airplane).

Normally I tune the VOR, hit the ID button on the GPS or second NAV radio, then press the corresponding button on the audio panel, wait for the tone, and shut it off.

I have identified the DME by itself in the past, by pressing the DME button on the audio panel and then waiting(for what seemed like an eternity) for the morse code.

I wasn't sure that if I waited long enough, that I would hear that DME tone through that NAV1, or not. Looks like not, but I'm not sure. Seems the safest way to do it would be to use both the NAV1 and DME buttons to be sure. I think I will need to sit in my airplane and try it(there is a VOR on the field).

Just making sure I have the little things down before the instrument checkride.
 
I agree with your procedure of IDing the DME separate from the Nav. Even if the DME was slaved off the NAV there is no guarantee that the DME is "seeing" the same station.
 
I pulled the airplane out of the hangar this afternoon and tried it.

NAV1 selected on the audio panel, DME morse code every 10 seconds, no higher-pitched identifier.

DME selected, high pitched DME tone only every 30 seconds. Along with a lot of static LOL.

You can't have them both on at the same time... if you do, you only hear NAV1.

Glad I tried this on the ground.

That said, does anyone know how if there is a way to adjust the DME volume? The ID knobs on the nav radios have a volume, but I don't think there is one on the DME and it is VERY loud in the headset, to the point of being painful. GMA340 audio panel, but playing with the knobs on it did nothing. The DME is a King KN-64...
 
Found a manual for the KN64 online. There is an audio level control, accessible through the top cover. I would not imagine this is very helpful information.

The typical use of a DME is that it is somehow slaved to the Nav radio to choose the right channel for you automatically. But you can tune it separately. And you don't need a conversion chart to know which channel corresponds to which VOR or localizer frequency. Just look at the communication box for th VOR on your chart and tune in the channel number it specifies for DME.
 
Sorry if this has been asked before. If you have glass and your HSI displays the station ID you are tuned to, do you still need to listen to the Morse, or is confirming the identifier visually sufficient?
 
rolivi said:
Sorry if this has been asked before. If you have glass and your HSI displays the station ID you are tuned to, do you still need to listen to the Morse, or is confirming the identifier visually sufficient?
Click to expand...
I think it depends on how the avionics determine what identifier to show. The Garmin GTN 650 and GNC 255 both claim to decode the station identifier to display it for you. That would provide positive identification. But they could also determine which station you are using from a GPS position and just show the identifier of the nearest navaid on the frequency you have tuned, which would not provide positive identification (such as if the VOR were out of commission and you got "lucky" and picked up a same-frequency VOR from the next state over). My conclusion is that the Morse-decoding-avionics method is just fine but the GPS-best-guess method is not.
 
The GNS units (and I assume the GTN) will show you the decoded morse code ID.
 
Last edited:
I used DME for the first time while getting an IPC after many years. I got the same thing, gawd awful noise that I could barely make out the ID through. Listening to that waiting for the ID to roll around while trying to listen to a busy approach frequency sucked. More than once I turned it off and said "I wouldn't actually do this approach with DME minimums." and then went ahead and did it anyway. The DME's in the planes I was flying were Kings, 64's as I recall.
 
Interesting. I'll have 430W and SL30 both feeding to a Dynon EFIS. I''ll need to verify but I think it is using decoded Morse.

Thanks!
 
Well since the SL30 has no database of it's own, it's not likely guessing. The only message from the SL30 that has an ID in it is the "Decoded Station Identifier" message. It either returns a 0 if no value is present or a V followed by the space padded identifier.

Near as I can see the 430 doesn't tell any external device information about a tuned station, only distance and id of a waypoint it is set up for.
 
rolivi said:
Sorry if this has been asked before. If you have glass and your HSI displays the station ID you are tuned to, do you still need to listen to the Morse, or is confirming the identifier visually sufficient?
Click to expand...
In my airplane the digital station ID is DME, not VOR. Pull the CB for VOR or DME and see which one makes the digital ident go away.
 
fiveoboy01 said:
When you tune a VOR-DME, do you identify them separately even though the frequencies are the same?

I know that the(higher pitched) coded identifer sounding every 30 seconds means that only the DME is operative, but I'm not sure if hearing the VOR portion means they are both operative.
Click to expand...
Just to answer the OP's question: hearing the VOR identifier tells you the VOR ID and that it's operational. Doesn't tell you anything about the status of any DME that it might be paired with. Hearing the DME identifier tells you the DME ID and that it's operational. That is all.
 
Thanks! That is originally the question I had, but I might have worded it poorly.

I did figure out the answer, but there it is. Maybe a student will read it someday and it will be helpful:)
 
You must log in or register to reply here.
Back
Top