[Milsurplus] Naval Aviation Navigation

[Peter Gottlieb]

DME uses pulse pairs with a fixed, calibrated response delay.  The range 
given is what's called slant range and not map distance, so if you are 
at 30,000 feet and right over the VORTAC (VOR-TACAN) it will show 5 naut 
miles.  In civilian VORTACs there is a combination of civilian VOR for 
azimuth info and a DME/TACAN subset for distance info.

Peter


D C *Mac* Macdonald wrote:
> I had thought that the DME portion was actually a
> transponder that sent out the pulse in response to
> an interrogation signal from the aircraft.  Admittedly,
> it's been a long time since I had contact with this
> sort of thing.  Last time I worked in avionics was
> in 1984 and tech school was long before that!
>
> 73  ---  Mac, K2GKK/5
>
>
>
> ----Original Message Follows----
> From: C Whitaker <whitaker at pa.net>
> Reply-To: whitaker at ieee.org
> To: "D C (Mac) Macdonald" <k2gkk at juno.com>
> CC: whitaker at ieee.org, milsurplus at mailman.qth.net
> Subject: Re: [Milsurplus] Naval Aviation Navigation
> Date: Tue, 14 Mar 2006 09:30:04 -0500
>
> de WB2CPN
>
> Mac, the antenna wouldn't have to rotate and produce
> the azmuth information if all you wanted is DME.   On
> a VORTAC the VOR antenna rotates a heart-shaped
> pattern which makes the azmuth info.  The 12 uS pulsed
> DME signal antenna usually sits on top of the VOR antenna,
> is omni-directional, and doesn't rotate.
>
> 73  Clete
>
>
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