[Milsurplus] More info - DIFAR ASW system on P3

[Mike Feher]

The DIFAR sonobouys had a flux gate compass in them. DIFAR was the changed name from LOFAR with the DI indicating directional. LOFAR by itself meant Low Frequency Acoustical Ranging. The DIFAR system is the one I have a patent on that Brooke Clarke shared not all that long ago. 73 – Mike 

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

 

From: milsurplus-bounces at mailman.qth.net <milsurplus-bounces at mailman.qth.net> On Behalf Of Brian Harrison
Sent: Monday, July 6, 2020 10:03 AM
To: milsurplus listserv <milsurplus at mailman.qth.net>
Subject: [Milsurplus] More info - DIFAR ASW system on P3

 

All,

 

Here’s a response from Bill Baker of The Hickory Aviation Museum

(If anyone wants Bill’s email pse email me directly)

 

Tnx,

brian

kn4r

 

...

That system was the AQA-7 that "burned" the recorded data on paper.  In it's original form it was call the "Jezebel" and we'd often call the acoustic operators "Jez" even after it was long gone from the aircraft.   It would scroll like a fax machine and at the end of the mission, the paper would be turned in to the debriefing gang for reconstruction.  One positive thing was the paper was an immediate visible replay of the information gained by the sonobuoys and the operators would also write and do computations on the paper itself.  Plus an operator could cut off the paper and remove from the machine and review back in time while on the mission to maybe see if contact was missed.   The negative was the nasty smell this machine produced!!!!!!!   Initially the buoys were "Lofar", or basically the buoy would detect a sound and give the operator a circle around the buoy and it would take multiple buoys to localize to a small area to search.  "Difar" buioys, which provide sound recordings, but more importantly, direction from the buoy were the next important tool to be developed and replaced Lofar.  Two or three buoys with lines pointing to a noise source and there it is where those lines intersect.  The USN went away from the AQA-7 when the P-3C Update III came on line in the mid 1980s.  The acoustic processing system was now all computerized, Lofar buoys were a thing of the past.  The new system was called the UYS-1, and the big and probably final upgrade to that system was introduction "CHEX" or channel expansion, allowing the aircrews to have 99 channel capabilities for buoy channel numbers of buoys instead of only 32.   Now, all the data is recorded on tapes that had to be replayed on ground based computer systems to review the mission and compare with operator notes.  (Operators could not do this in-flight).  That system is what is featured in the Hickory Aviation Museum's P-3C, with plasma panels to enter data and manipulate the buoys.  When flying, the operator on the right was the lead, he'd usually do the Difar work, which was passive only, just listening for noise.  The other operator was usually in training and would help and also do the Dicass, or active buoys should they be authorized.  Dicass would provide a range and bearing from buoy to target with burst of energy, just like sonar..   I flew on aircraft with both systems, and a lot comes down to the quality of the operator and numerous other factors such as oceanographic conditions, and of course, the target itself.  Hope that answers the question, if not, let me know., I had 3k+ hours flying P-3C’s.

 

Hickory Aviation Museum - http://www.hickoryaviationmuseum.org/welcome.html

 

P3-C interactive tour - https://my.matterport.com/show/?m=4UgzaEpRdwr <https://my.matterport.com/show/?m=4UgzaEpRdwr&utm_source=4> &utm_source=4

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