Idents on VOR+DME if one of them is inop

Peter wrote:
I am just going through some King video FAA IR training material and
it briefly covers this topic.

On a normal intercom one has selectors for "DME" and "NAV" and one
would ident the VOR and the DME separately. However she mentions a
that one can tell if one or the other is inop from the period of the
ident. How does this work?

Is she assuming some sort of mixed-mode intercom where there is just
a
single "ident" selector? In that case, I can see that if the VOR
(only) was inop then the ident would be heard every 30 secs (the DME
ident) but what about if the DME (only) was inop? There would be some
sort of strange periodicity.

The period of the ident (a missing ident every 4 as I recall) indicates
that the DME is not being transmited. Listening to the DME on the audio
panel just tells you that you are receiving the VOR (and will provide
the same audio the VOR does). Its really a test of the instrument's
reception.

-Robert

Hope I have read you Q correctly...

the VOR idents every ten seconds, the DME every 30. So you should
hear...VOR, VOR,DME, VOR, VOR, DME et seq. every minute.

The DME ident is higher in pitch than a VOR ident to aid your understanding.

If one item is failed but transmitting, you'll hear VORt where the t is
meaning "test". Or the ident might be changed to "test" or "tst". Either
way if it isnt what you expect to hear, dont use it for serious nav.

HTH

David

Oops, sorry...VOR VOR VOR DME, VOR VOR VOR DME!

the VOR idents every ten seconds, the DME every 30. So you should
hear...VOR, VOR,DME, VOR, VOR, DME et seq. every minute.

Think about it like this..

The VOR and DME are TWO SEPARATE radios and nav systems. They are on
different frequency bands, different transmitters and the only
assiciation that they may have is 1) being in the same transmitter
building and 2) being "paired" frequency wise with a VOR/ILS frequency.

For instance, every DME frequency is "assigned" a corresponding VOR
frequency to buddy-up to it. That way you dont have to know, and tune,
the UHF frequency that the DME operates at. You simply set your DME
reciever to "slave" to your VOR/NAV radio to get the selected frequency
pair assignment or you can tune the DME manually to the VHF "VOR"
frequency of the pair

The same frequency pairing exists for Localizer + Glideslope
installation. You tune the localizer.. the radio is set up to look for
the glideslope signal on a separate but assigned/paired frequency.

The VOR Idents occur regularly.. every 10 seconds or so.. and are heard
by using the VOR ident function on your radio/audio panel.

The DME idents occur regularly but every 30 seconds or so. They are
heard using the separate DME ident function on your radio/audio panel.

As others have said, if you monitor BOTH simultaneously you will hear
one "higher pitched" DME ident for every three "lower pitched" VOR idents.

If one is inop, the other signal and functionality is not affected.
Again, the only thing that the two share is a site, and the "pairing" of
two different bands on two different frequencies.

My home base, EFD, used to have a terminal VORTAC but had the VOR
function decommissioned. The TACAN remains, and the DME function of the
TACAN is tuneable by tuning the DME to its "VOR frequency pair" of 109.4
mhz.

Dave

Peter wrote:
"david" wrote:


Oops, sorry...VOR VOR VOR DME, VOR VOR VOR DME!


the VOR idents every ten seconds, the DME every 30. So you should
hear...VOR, VOR,DME, VOR, VOR, DME et seq. every minute.



Is this true if one is using an intercom which has TWO buttons for
idents; one marked DME and the other marked NAV?

I don't understand how a DME ident can be (as a general rule)
incorporated into the VOR signal. One can have a DME without a VOR (an
ILS, or a TACAN). I can ident the DME on an ILS even if tuned to a
wrong ILS frequency (the DME on an ILS has a different ident from the
ILS anyway) and as far as I can remember from flying in Greece I can
ident the DME in a TACAN even though I can't receive the VOR part
because it's on UHF.


Peter.
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david wrote:

If one item is failed but transmitting, you'll hear VORt where the t is
meaning "test". Or the ident might be changed to "test" or "tst". Either
way if it isnt what you expect to hear, dont use it for serious nav.

I was flying along in the back seat while Margy and her instructor where in
the front. They figured out the VOR was acting loopy and were listening
to the ID. They pretty much figured out it wasn't sending EMI, but they
were stumped. Finally, I pointed out it was sending TEST. (...and Margy
is an Advanced class amateur radio operator to boot!).

Peter wrote in
:
Is this true if one is using an intercom which has TWO buttons for
idents; one marked DME and the other marked NAV?

Yes. If you listen to both simultaneously that's what you will hear. If
you only listen to one, then you'll only hear the one you're monitoring.

I don't understand how a DME ident can be (as a general rule)
incorporated into the VOR signal.

It isn't. It's on a separate frequency, but paired to the associated VOR
frequency. But it's easy to combine both signals through one switch,
thus saving a little money on the unit, and some prefer to hear both. I
prefer having separate monitor switches, but you can combine as many
signals as you like into one switch.

--
Regards,

Stan

Stan Gosnell wrote:
I don't understand how a DME ident can be (as a general rule)
incorporated into the VOR signal.

It isn't. It's on a separate frequency, but paired to the associated VOR
frequency. But it's easy to combine both signals through one switch,
thus saving a little money on the unit, and some prefer to hear both. I
prefer having separate monitor switches, but you can combine as many
signals as you like into one switch.

I assume at the VOR-DME ground station, the audio generators for the
VOR and DME must somehow be syncronized with each other, so the two
id's don't get scrambled?

Yeah but thats not hard surely? Each tx is synchd to a clock and the clocks
are set to zulu.


"Roy Smith" wrote in message
...
Stan Gosnell wrote:
I don't understand how a DME ident can be (as a general rule)
incorporated into the VOR signal.

It isn't. It's on a separate frequency, but paired to the associated VOR
frequency. But it's easy to combine both signals through one switch,
thus saving a little money on the unit, and some prefer to hear both. I
prefer having separate monitor switches, but you can combine as many
signals as you like into one switch.

I assume at the VOR-DME ground station, the audio generators for the
VOR and DME must somehow be syncronized with each other, so the two
id's don't get scrambled?

Peter wrote:


I am doing the FAA IR from the UK, and thought that perhaps they have
a system in the USA where (the case of the DME and the VOR being
co-located) the DME ident is combined into the VOR ident. Certainly
the King training video gives that impression, but it doesn't make any
sense to me.


While I've never used the King Video, I understant they are popular.

Every plane I've flown that had a DME had a separate switch on the audio
panel for the DME. When I went to Ident, however, I usually selected
both the VOR I was using AND the DME as a matter of expediency. So..
sorry that you ended up with faulty info.. but they are actually
separate in all regards except frequency pairing and location.... and
the location rule isn't hard and fast...

I recall there are a few approaches that use an ILS... but you tune the
DME from the on-field VORTAC for DME information during the approach.
Two separate installations altogether.. and in this case, the idents
would be different as well.

Dave

Peter asked, "... does anyone actually do that [identify DME and VOR
together] , if they have an intercom which has separate DME/VOR ident
buttons, for navaids that have the same ident?"

Yes. I identify both at the same time and switch off whichever one I hear
first.

Jon