[ARC5] ASV radar for a PBY

Fri Mar 11 08:28:46 EST 2022

Don't know if anyone posted this (haven't caught up),
but for those interested:
https://www.uboat.net/allies/technical/uk_radars.htm
https://pacificeagles.net/wp-content/uploads/2017/10/ASV-Mark-II-L-Scope.jpg
https://upload.wikimedia.org/wikipedia/commons/9/90/IMG_2718_%289125829780%29.jpg
https://military-history.fandom.com/wiki/ASV_Mark_III_radar
https://iopscience.iop.org/book/978-1-6432-7066-1/chapter/bk978-1-6432-7066-1ch1

On 3/10/2022 4:02 PM, taigh at twinbeech.com wrote:
>
> Hello Ray,
>
> I wish this PBY had an ASB set as we can still find those components 
> and life would be much easier.
>
> I would just like to start off with a manual or photos showing the ASV 
> components so I can start looking and spreading the word.
>
> Going by the available photos I have come across, there seems to have 
> been quite a few early PBY installations using the Sterba array.
>
> Attached are photos of a wartime Sterba on a PBY and a shot taken 
> yesterday of the antenna mooring fittings still on the top of the aft 
> fuselage after 80 years. Fun detective work indeed.
>
> Thanks,
>
> Taigh
>
> Taigh Ramey
>
> Vintage Aircraft Inc.
>
> 7432 C.E.Dixon Street
>
> Stockton, California 95206
>
> (209) 982-0273
>
> (209) 982-4832 Fax
>
> www.twinbeech.com <http://www.twinbeech.com/>
>
> /KEEP 'EM FLYING...FOR HISTORY!/
>
> *From:* raydio862 at verizon.net <raydio862 at verizon.net>
> *Sent:* Thursday, March 10, 2022 6:44 AM
> *To:* 'Bart Lee' <kv6lee at gmail.com>; 'Taigh Ramey' <taigh at twinbeech.com>
> *Cc:* Vintage-Military-RADAR at yahoogroups.com; 'ARC5' 
> <Arc5 at mailman.qth.net>; 'milsurplus at mailman' <milsurplus at mailman.qth.net>
> *Subject:* RE: [ARC5] ASV radar for a PBY
>
> Bart & Taigh,
>
> That’s fantastic information, I was not aware of the use of the Sterba 
> array antenna to improve search capability.  But the account clearly 
> describes the ASB radar system with two yagi antennae.  The vertical 
> “A” display is actually called a “B” scan with pips to the right and 
> left from the two yagi antennae.  Equalizing the pips points the 
> aircraft to the target.  As I indicated previously, the ASB operated 
> at 515 Mhz with conventional vacuum tubes.  The article is a testimony 
> to the cooperation between the Brits and Americans to exploit the 
> benefits of ASV type radar.  I am not familiar with the British Mk ASV 
> radars but I believe that the ASB equipment was a big improvement on 
> the original British ASV system hardware.  I do not think that the 
> Sterba array was used too much as I never ran across it before. I’m 
> sure the pilots loved it as it must have really altered the PBY flight 
> characteristics.
>
> I have a complete ASB-4 system without antennae but with a few 
> duplicate units including a duplicate indicator scope.  I also have 
> some tech manuals and some details on the yagi antenna that I obtained 
> from the National Electronics Museum (NEM).  I am a radar historian 
> and curator of the Radio Technology Museum (RTM) at the campus of the 
> InfoAge Science and History Center in Wall, New Jersey.  In my years 
> of searching, I have not been able to find one of the original yagi 
> antenna.  Over 20,000 ASB systems were produced during WWII with 
> variations as technology improved.  I think the major intended use was 
> for single engine carrier borne aircraft.  As far as I know, it was 
> the first use of aircraft search and fire control radar by the United 
> States.
>
> I will supply as much help as I can for your project.
>
> Ray
>
> *From:* arc5-bounces at mailman.qth.net <arc5-bounces at mailman.qth.net> 
> *On Behalf Of *Bart Lee
> *Sent:* Thursday, March 10, 2022 1:23 AM
> *To:* Taigh Ramey <taigh at twinbeech.com>
> *Cc:* Vintage-Military-RADAR at yahoogroups.com; ARC5 
> <Arc5 at mailman.qth.net>; milsurplus at mailman <milsurplus at mailman.qth.net>
> *Subject:* Re: [ARC5] ASV radar for a PBY
>
> Taigh, FWIW, here's some background on the British development of Air 
> to Surface Vessel (ASV) Radar and the use of the Sterba antenna:
>
> PBY ASV RADAR (Air >> Surface Vessel)
>
> Sterba Antenna on the PBY (and/or Catalina)
>
> ==. ==
>
> http://www.warbirdinformationexchange.org/phpBB3/viewtopic.php?p=524687 
> <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
>
> ==. ==
>
> [British development]
>
> Shortly after moving to St. Athan in 1939, Hanbury Brown received a 
> request to fit ASV to the Armstrong Whitworth Whitley 
> <https://military-history.fandom.com/wiki/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 
> <https://military-history.fandom.com/wiki/ASV_Mark_II_radar>
>
> ==. ==
>
> 73 de K6VK 09 III 22 ##
>
> -- --
>
> Bart Lee, K6VK, CHRS Archivist and Fellow, AWA Fellow, ARRL Liaison
>
> Texts only to: 415 902 7168
>
> www.bartlee.com <http://www.bartlee.com/>
>
> {KV6LEE(at)gmail(dot)com} ##
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