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.

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!).