[Milsurplus] Re: Milsurplus Digest, Vol 28, Issue 18

[Rian Robison]

Have an old Navy book that tells how they used to home-in to find their way.  Planes with a gunner/ radio or radio operator used a DF attachment that had a sense antenna and thus could tell which way the station was.  However, fighters only had a loop (which was installed in that round headrest pad behind the pilot's head).  The pilot would align the plane to the loudest signal and note his heading.  He then would turn the plane 90 degrees and fly for awhile (an 1/2 hour or more was suggested).  He would then turned back toward his first signal peak heading and line up on the strongest signal again.  If the two headings were such that they would converge ahead of him somewhere, he would continue to fly toward the signal source.  Of course if the two headings would never converge, he would turn 180 and fly the other way.  This was what the book said to do but if you think how HF signals travel, I wonder how good this really worked in practice.  That training flight that was lost off of Florida back in WWII could most likely tell us it didn't work too well if they were trying it.

I can say that using an ARN-6 in an A3D bomber (LF and MF) worked pretty well both at 200 feet or so and at higher ones (25,000 to 45,000 plus).  Back in 1960 no airliners got up over 40,000.  We flew direct (as a crow would fly if they could) above 45,000 between WB Island, Washington and Pen, Florida several times and it worked fine I believe.  The draw back to flying at this height was the oxg regulator auto-switched to pressure breathing which was work to exhale and tired you out.  You try to relay and rest a little and right away you would be blown up like a balloon, it felt like.

Rian

-----Original Message-----
>From: Brooke Clarke <brooke at pacific.net>
>Sent: Aug 16, 2006 7:39 PM
>To: milsurplus at mailman.qth.net
>Subject: [Milsurplus] Re: Milsurplus Digest, Vol 28, Issue 18
>
>Hi Breck:
>
>It's my understanding that a loop does not work very well when sky wave 
>signals are being received.  The Watson-Watt set of 4 vertical dipoles 
>works much better.  So any W.W. II vintage aircraft DF system in the 3 - 
>30 Mhz range would need be be based on an antenna system that's not very 
>compatible with aircraft.
>
>Modern aircraft use HF time of arrival DF methods for this frequency 
>range, like those made by TCI, and the antennas can be completely unseen.
>
>Have Fun,
>
>Brooke Clarke, N6GCE
>
>-- 
>w/Java http://www.PRC68.com
>w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
>http://www.precisionclock.com
>
>
>>Date: Wed, 16 Aug 2006 09:58:03 -0400
>>From: "B. Smith" <smithab11 at comcast.net>
>>Subject: [Milsurplus] Aircraft HF  DF capabilities
>>To: "milsurplus" <milsurplus at mailman.qth.net>
>>Message-ID: <000501c6c13b$ff044920$3b19c847 at HAL1000>
>>Content-Type: text/plain; format=flowed; charset="Windows-1252";
>>	reply-type=original
>>
>>DF capabilities
>>
>>Does anyone know of any WWII aircraft receiver or receiver system that had 
>>airborne Direction Finding (DF) capabilities in the   3.0 to 18 Mcs ranges. 
>>Using either automatic or manual antenna operation.
>>
>>I am currently working on a fairly  precise homebrew copy of the British 
>>Type 3 DF antenna  and using it with the R1155A receiver.  The R1155 manuals 
>>states that the receiver can be used on the higher HF frequencies mentioned 
>>above as well as the normal navigation frequencies  1600 Kcs and below.
>>
>>breck k4che 
>>
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