The Barlow Wadley XCR 30 receiver is an exceptional device for its design and performance, it bears the name of the factory that produced it, the Barlow Television Company, but also the name of the engineer Dr Trevor Lloyd Wadley who designed the ingenious system. which equips this receiver.
https://www.radiomuseum.org/r/barlow_xcr_30_mark_2_ii.html
During World War II while working for the Royal Air Force's Telecommunications Research Establishment (TRE), Dr. Wadley
https://en.wikipedia.org/wiki/Trevor_Wadley
https://www.qsl.net/pa2ohh/06barlow.htm
developed a circuit that suppressed any frequency drift. This "Wadley loop" system is based on the use of a single reference quartz with a value of 1Mhz to generate harmonics, which allow great stability of the received frequency, eliminating any frequency slip while offering high selectivity.
The first known receiver using the "Wadley loop" is the RACAL RA-17,
https://f6blk.net/main_fr.php?page=64
it was produced in the early 1950s and used by the British army and the commercial navy until the arrival of its replacement the RACAL RA- 117 in the early 1970s.
In the mid-1960s, back in South Africa, where he was born, Dr Wadley worked on the design of a portable transistorized receiver which was finally produced in 1971 by the "Barlow Television Company" after the takeover of the local activities of RACAL-SMD.
From the end of 1971 to 1982, around 20,000 units of the Barlow Wadley XCR 30 will be produced and marketed in Africa but also in the rest of the world with serious supply difficulties linked to the boycott of many countries towards products from South Africa for cause. practice of Apartheid.
The Barlow Wadley XCR 30 is a 0.5 to 30 Mhz continuous coverage consumer portable HF receiver with performance equivalent to traffic receivers of this period.
Si le Barlow Wadley fait figure d’appareil réellement exceptionnel, il faut préciser que les performances obtenues sur ce modèle incita quelques années plus tard de nombreux constructeurs à reprendre le système de la « boucle Wadley » dans la conception de leurs récepteurs, ce fut le cas des Yaesu FRG-7, Drake SSR-1, Lowe SRX 30, Standard C-6500 et Century 21.
Depuis son lancement fin 1971 et pendant près d’une décennie, le Barlow Wadley XCR 30 restera l’un des récepteurs les plus prisés par les écouteurs, DXeurs et SWL de part le monde.
Dans les bulletins compilés par Georges Bjarne "La Suède appelle les DXeurs", émission DX diffusée par Radio Suède, le Barlow Wadley sera souvent cité dans les rapports d’écoute transmis par les auditeurs fanas de réception longue distance.
http://www.f1nqp.fr/fichier/ArticleDuHautParleur.pdf
I translate this article from a French blog
https://www.cryptomuseum.com/spy/xcr30/index.htm
https://webspace.science.uu.nl/~tel00101/FotoAlbum/RadioCorner/Articles/Barlow30.htm
https://www.qsl.net/pa2ohh/06barlow.htm
The "Wadley-drift-canceling-loop", also known as a "Wadley loop", is a system of two oscillators, a frequency synthesizer, and two frequency mixers in the radio-frequency signal path. The system was designed by Dr. Trevor Wadley in the 1940s in South Africa. The circuit was first used for a stable wavemeter. (A wavemeter is used for measuring the wavelength and therefore also the frequency of a signal)
There is no regulation loop in a "Wadley-loop", which is why the term is in quotation marks. However, the circuit configuration is not known by more accurate names.[2]
The "Wadley loop" was used in radio receivers from the 1950s to approximately 1980. The "Wadley loop" was mostly used in more expensive stationary radio receivers, but the "Wadley loop" was also used in a portable radio receiver (Barlow-Wadley XCR-30 Mark II).[3][4]
http://madrona.ca/e/radio/RacalRA117/
If the Barlow Wadley is a truly exceptional device, it should be noted that the performance obtained on this model prompted many manufacturers a few years later to use the "Wadley loop" system in the design of their receivers, this was the case of the Yaesu FRG-7, Drake SSR-1, Lowe SRX 30, Standard C-6500 and Century 21.
Since its launch in late 1971 and for nearly a decade, the Barlow Wadley XCR 30 will remain one of the most popular receivers for headphones, DXers and SWLs the world over.
In the bulletins compiled by Georges Bjarne "Sweden calls the DXers", a DX program broadcast by Radio Sweden, the Barlow Wadley will often be cited in the listening reports transmitted by listeners who are fans of long-distance reception.
https://www.f1nqp.fr/index.php?lng=fr
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