[Milsurplus] Naval Aviation Navigation

[James Duffer]

I believe your recollection is correct.  The director rotated around the 
radiator at a specified rate creating "space modulation" at the aircraft's 
receiver which was compared to a transmitted reference signal establishing 
azimuth information.  The distance was established by time measurement 
between the interrogation and reception signals, sort of a reverse 
arrangement where the transponder is located at the facility and the 
interrogator in the aircraft (sort of the reverse of ATCRB, air traffic 
control radar beacon.  Squitter was used to allow continious azimuth 
information (regardless of interrogation rate).  This is recollection from 
over 40 years ago when a AN/GRN-9 TACAR was going to be added to the VOR on 
Jekyl Island GA may be in error from fading memory Hi.

Retire FAA, Jim  wd4air

>From: "D C *Mac* Macdonald" <k2gkk at hotmail.com>
>To: whitaker at ieee.org, k2gkk at juno.com
>CC: milsurplus at mailman.qth.net
>Subject: Re: [Milsurplus] Naval Aviation Navigation
>Date: Tue, 14 Mar 2006 14:37:59 +0000
>
>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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