AI Mark IV radar

**Radar, Airborne Interception, Mark IV** ( **AI Mk. IV** ), wanda Amurka ta samar a matsayin **SCR-540**, shine tsarin radar na farko na iska zuwa iska na farko a duniya. Farkon Mk. Rukunin III sun bayyana a cikin Yuli 1940 akan masu tayar da bama-bamai masu haske na Bristol Blenheim, yayin da tabbataccen Mk. IV ya kai yawan samuwa a kan Bristol Beaufighter babban mayaki a farkon 1941. A kan Beaufighter, Mk. IV mai gardama ya taka rawa wajen kawo karshen Blitz, yaƙin neman zaɓe na dare *na Luftwaffe* na ƙarshen 1940 da farkon shekarar 1941.

Ci gaban farko ya samo asali ne ta hanyar bayanin 1936 na Henry Tizard kan batun fadan dare. An aika da bayanin zuwa Robert Watt, darektan kokarin bincike na radar, wanda ya yarda ya ba da izini ga masanin kimiyya Edward George "Taffy" Bowen don samar da wata ƙungiya don nazarin matsalar iska. Ƙungiyar tana da tsarin gado na gwaji a cikin jiragen sama daga baya a waccan shekarar, amma an jinkirta ci gaba har tsawon shekaru hudu ta hanyar ƙaura na gaggawa, ƙirar samarwa guda uku da aka watsar, da kuma dangantakar abokantaka ta Bowen tare da maye gurbin Watt, Albert Percival Rowe . Daga ƙarshe, an tilasta Bowen daga ƙungiyar kamar yadda tsarin ya fara girma.

A Mk. Jerin IV yana aiki a mitar kusan 193&nbsp;megahertz (MHz) tare da tsawon 1.5&nbsp;mita, kuma an ba da jeri na ganowa akan manyan jirage har zuwa  . Yana da iyakoki na aiki da yawa, gami da iyakar iyakar da ta karu tare da tsayin jirgin da mafi ƙarancin kewayon da ya yi kusa da bai isa ya ba matuƙin jirgin damar ganin abin da aka nufa ba. Ana buƙatar fasaha mai mahimmanci daga ma'aikacin radar don fassara nunin bututun ray na cathode (CRTs) na matukin jirgi. Sai kawai tare da haɓaka ƙwarewar ma'aikatan, tare da shigar da sababbin tsarin radar na ƙasa wanda aka keɓe don aikin tsaka-tsakin, adadin shiga ya fara karuwa. Waɗannan kusan ninki biyu kowane wata har zuwa bazara na shekarata 1941, a lokacin tsayin The Blitz.

A Mk. An yi amfani da IV a cikin layin gaba na ɗan gajeren lokaci. Gabatar da magnetron rami a cikin 1940 ya haifar da saurin ci gaba a cikin radar mitar microwave, wanda ya ba da daidaito mafi girma kuma yana da tasiri a ƙananan tudu. Samfurin Mk. VII ya fara maye gurbin Mk. IV a karshen 1941, da AI Mk. VIII ya fi mayar da Mk. IV zuwa ayyukan layi na biyu ta 1943. A Mk. An yi amfani da mai karɓar IV, asalin mai karɓar talabijin, a matsayin tushen ASV Mk. II radar, Chain Home Low, AMES Type 7, da sauran tsarin radar da yawa a duk lokacin yakin.

## Ci gaba

### Farawa
A ƙarshen 1935, haɓakar Robert Watt  na abin da aka fi sani da Range and Direction Finding (RDF) a Bawdsey Manor a Suffolk a gabashin gabar tekun Ingila ya yi nasarar gina tsarin da zai iya gano manyan jirage a jeri. fiye da  .  A ranar 9 ga Oktoba, Watt ya rubuta wata takarda ta kira don gina jerin tashoshin radar da ke gudana a gabar gabashin Ingila da Scotland, mai nisan  baya, yana ba da gargaɗin farko ga dukan tsibiran Biritaniya. Wannan ya zama sananne da Chain Home (CH), kuma nan da nan sai radars da kansu suka zama suna da suna iri ɗaya. Ci gaba ya ci gaba, kuma a ƙarshen 1935 kewayon ya inganta zuwa sama da , rage yawan tashoshin da ake buƙata. 

A lokacin 1936 an gwada tsarin gwaji a Bawdsey akan hare-hare iri-iri, tare da ci gaba mai yawa na ka'idar shiga tsakani da aka gudanar a RAF Biggin Hill . Daya daga cikin masu lura shine Hugh Dowding, da farko a matsayin darektan bincike na RAF, kuma daga baya a matsayin kwamandan rundunar RAF Fighter Command . Dowding ya kara da cewa, tashoshin CH na bayar da bayanai da yawa, ta yadda masu gudanar da aikin ke samun matsala wajen isar da su ga matukan jirgi, kuma matukan jirgin sun samu matsala wajen fahimtarsa. Ya magance hakan ne ta hanyar samar da abin da a yau ake kira da tsarin Dowding . 

Tsarin Dowding ya dogara da hanyar sadarwar tarho mai zaman kansa yana isar da bayanai daga tashoshin CH, Royal Observer Corps (ROC), da kuma gano hanyoyin rediyo na pip-squeak (RDF) zuwa wani ɗaki na tsakiya inda aka tsara rahotannin akan babban taswira. Daga nan ne aka tuntubi wannan bayanin ta wayar tarho zuwa hedkwatar Rukunin yanki guda hudu, wadanda suka sake kirkiro taswirar da ke kunshe da yankin ayyukansu. Daga nan za a aika da cikakkun bayanai daga waɗannan taswirori zuwa ga kowane Sassan Ƙungiya, wanda ya shafi manyan tashoshin jiragen sama ɗaya ko biyu, daga nan zuwa ga matuƙan ta hanyar rediyo. Wannan tsari ya ɗauki lokaci, lokacin da jirgin da aka yi niyya ya motsa. Kamar yadda tsarin CH yayi daidai kawai zuwa kusan 1&nbsp;km mafi kyau,  rahotannin da suka biyo baya sun warwatse kuma ba za su iya sanya manufa daidai ba fiye da  .  Wannan yana da kyau don tsaka-tsakin rana; Da ma matukan jirgi sun saba hango abin da suke hari a cikin wannan kewayon. 

### Dare bam
Henry Tizard, wanda Kwamitin binciken Kimiyya na Tsaron Sama ya jagoranci haɓaka tsarin CH, ya damu da cewa CH zai yi tasiri sosai. Ya yi tsammanin cewa *Luftwaffe* za ta yi hasarar da yawa ta yadda za a tilasta musu dakatar da hare-haren da rana, kuma za su koma yunkurin tayar da bam.  Magabata a Yaƙin Duniya na ɗaya sun yi daidai lokacin da Yankin Tsaron Sama na Landan ya yi nasarar hana hare-hare da rana, kuma yunƙurin kutsa kai harin bama-bamai na Jamus da daddare ya zama abin ban dariya. Damuwar Tizard zai tabbatar da annabci; Bowen ya kira shi "daya daga cikin mafi kyawun misalan hasashen fasahar da aka yi a karni na ashirin". 

Tizard was aware that tests showed an observer would only be able to see an aircraft at night at a range of about , perhaps  under the very best moonlit conditions, an accuracy that the Dowding system could not provide. Adding to the problem would be the loss of information from the ROC, who would not be able to spot the aircraft except under the very best conditions. If the interception was to be handled by radar, it would have to be arranged in the short time between initial detection and the aircraft passing beyond the CH sites on the shoreline.

Tizard ya sanya tunaninsa a cikin wasiƙar 27 Afrilu 1936 zuwa Hugh Dowding, wanda a wancan lokacin Memba ne na Bincike da Ci gaba . Ya kuma aika kwafin zuwa Watt, wanda ya tura shi ga masu binciken da ke ƙaura zuwa sabuwar tashar binciken su a Bawdsey Manor.  A cikin wani taro a mashaya Crown da Castle, Bowen ya danna Watt don izinin kafa ƙungiya don nazarin yiwuwar sanya radar a kan jirgin da kansa.   Wannan yana nufin tashoshin CH kawai suna buƙatar shigar da mayaki a cikin babban yanki na maharin, mayaƙin zai iya amfani da nasa radar don sauran tsangwama. Watt daga ƙarshe ya gamsu cewa ma'aikatan da ake buƙata don tallafawa ci gaban CH biyu kuma an sami sabon tsarin, kuma an cire rukunin Airborne daga ƙoƙarin CH a watan Agusta 1936. 

### Ƙoƙarin farko

Bowen ya fara ƙoƙarin radar Interception (AI) ta hanyar tattaunawa game da batun tare da injiniyoyi biyu a kusa da RAF Martlesham Heath, Fred Roland, da NE Rowe. Ya kuma kai ziyara da dama a hedkwatar Rundunar Fighter a RAF Bentley Priory kuma ya tattauna dabarun fada da dare tare da duk wanda ya nuna sha'awar.  Ma'auni na farko don radar iska, wanda ko dai matukin jirgi ko mai kallo ke aiki, sun haɗa da:

* nauyi kada ya wuce  ,
* shigar sarari na    ko fiye,
* matsakaicin ikon amfani da 500&nbsp;W ( watts ), kuma
* eriya mai  tsayi ko ƙasa da haka. 

Bowen ya jagoranci sabuwar ƙungiya don gina abin da ake kira RDF2 a lokacin, tsarin asali ya zama RDF1.  Sun fara neman tsarin karban da ya dace, kuma nan da nan suka sami bugun jini; Kwanan nan EMI ta ƙera mai karɓar samfuri don watsa shirye-shiryen talabijin na gwaji na BBC akan 6.7&nbsp;m tsawo (45&nbsp;MHz). Mai karɓa yayi amfani da bututu bakwai ko takwas (valves)  akan chassis  tsayi kuma kusan  tsawo. Haɗe tare da nunin CRT, tsarin gabaɗayan yana auna  . Daga baya Bowen ya bayyana shi a matsayin "mafi nisa da nesa fiye da duk wani abu da aka samu a Biritaniya har zuwa lokacin." 

Maimakon haka, an karɓi tsarin eriya masu karɓa da yawa, kowanne yana samuwa ta yadda wani yanki na sararin samaniya kawai ake iya gani. An ɗora masu karɓa biyu a kwance a kowane gefe na fuselage kuma kawai sun ga tunani daga hagu ko dama, ɗan ɗanɗana a tsakiya. An ɗora masu karɓa biyu a tsaye sama da ƙasa da reshe, suna ganin tunani sama ko ƙasa da jirgin. OkKo da a cikin 1.5&nbsp;m tsawo, eriya masu girman aiki suna da ƙarancin riba da ƙarancin ƙuduri; eriyar mai watsawa ta ƙirƙiri sigina mai siffar fan sama da faɗin digiri 90. Wannan ba shi da amfani don homing akan manufa, don haka ana buƙatar wasu tsarin nunin jagora. Ƙungiyar ta ɗauki kwatancen lokaci da gaske a matsayin mafita, amma ba ta iya samun da'irar canjin lokaci mai dacewa ba. 

A wannan lokacin ma'aikatar jiragen sama ta yi fatan samun kowace na'ura ta aiki. Da gamsuwa da ziyararsa a watan Mayu, Dowding ya ba da shawarar cewa Mk. Na yi kyau don dalilai na gwaji na aiki. A kan 11 Yuni 1939, AI an ba da fifiko mafi girma kuma an yi tanadi don samar da ƙarin Blenheims 11 zuwa No 25 squadron a RAF Hawkinge (don jimlar 21). Tun da kowane ɓangaren ya fito ne daga masu ba da kaya daban-daban, kuma masu dacewa ba su da masaniya da kowane ɗayansu, membobin ƙungiyar AI dole ne su haɗa abubuwan da aka haɗa da hannu yayin da suka isa kuma suna ba da umarni masu dacewa akan saiti.