PBY ASV RADAR (Air >> Surface Vessel)

Sterba Antenna on the PBY (and/or Catalina)

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http://www.warbirdinformationexchange.org/phpBB3/viewtopic.php?p=524687

If my memory serves me correctly,  the search antenna was a Sterba Array which stretched between the aft section of the wing and the tail emphanage and provided a figure "8"  transmit/receive pattern for search,  and when a target was acquired,  the radioman informed the pilot of the direction (i.e. port or starboard) of the target acquisition ... the pilot reported back to the radioman, "OK, making a turn to Starboard... or Port, ... as required"..... at that time the radioman would shut down the ASB (we used to refer to it as the Baker gear) modulator,  manually disconnect the two Sterba Curtain Array coaxial cables from the motor driven mechanical switch,  attach the the two coaxial cables driving the Port and Starboard Yagi antennas having a relatively forward uni directional mode ... again power up the ASB modulator ... and then with his vertical "A"  RADAR display  direct the pilot either "right or left" as required to display equal amplitudes of the vertical "A" display " pips ... indicating a "homing in" mode.    Long time ago,  but as I recall,  the maximum range was 80 KM... but I stand corrected if anyone wants to dispute that figure. [Don't ever remember acquiring any targets at that range ... however!!!]  Jeez!   What an improvement  ARPA Radar and Raster Scan of Sperry Radar for Merchant Marine...Collision Avoidance System RADAR  (CAS) has been since that time!!! 

Walt B. #5507

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[British development]

Shortly after moving to St. Athan in 1939, Hanbury Brown received a request to fit ASV to the Armstrong Whitworth Whitley bomber, which was no longer competitive and was being passed off to other uses. Brown took the chance to develop a new antenna, a type of Sterba array, that stretched along both sides of the flat rear fuselage, firing to the side instead of forward. This "broadside array" allowed the aircraft to search wide areas of the ocean on both sides of the aircraft at the same time, a great improvement over the forward-only design.

The broadside array offered about 2.5 times the gain of the original system. This allowed it to detect moderate-sized ships at 40 miles (64 km) and surfaced submarines at 10 to 15 miles (16–24 km), an enormous advance over the Mk. I style antennas. The aircraft could scan the approaches to a convoy by flying 10 miles to one side of it, sweeping a 20-mile wide path. Submarines were not fast enough to cross that distance before the aircraft had returned for another sweep. There was some discussion of giving it a special display to make interpretation easier, but it went into service using the original ASV display instead.

https://military-history.fandom.com/wiki/ASV_Mark_II_radar

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73 de K6VK 09 III 22 ##