[Milsurplus] Naval Aviation Navigation

[James Duffer]

What?!  No cone of silence?  The interrogation is accomplished by 
transmitting a pair of pulses 3.5 microseconds wide and separated by 12 
microseconds from the interrogator on the aircraft at an assigned TACAN 
frequency.  These pulse pairs are received by the transponder beacon 
examined for proper characteristics (width, spacing) and if acceptable 
generate a reply pulse pair.  The time of the two way travel plus processing 
time is converted to distance in nautical miles.

Jim de wd4air


>From: Peter Gottlieb <pgottlieb at hudsonshores.com>
>Reply-To: pgottlieb at hudsonshores.com
>To: D C *Mac* Macdonald <k2gkk at hotmail.com>
>CC: whitaker at ieee.org, k2gkk at juno.com, milsurplus at mailman.qth.net
>Subject: Re: [Milsurplus] Naval Aviation Navigation
>Date: Tue, 14 Mar 2006 09:54:45 -0500
>
>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
>>
>>
>>______________________________________________________________
>>Milsurplus mailing list
>>Home: http://mailman.qth.net/mailman/listinfo/milsurplus
>>Help: http://mailman.qth.net/mmfaq.htm
>>Post: mailto:Milsurplus at mailman.qth.net
>>
>>
>______________________________________________________________
>Milsurplus mailing list
>Home: http://mailman.qth.net/mailman/listinfo/milsurplus
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:Milsurplus at mailman.qth.net