rca: BP-10 article |
Tom Warnagiris ![]() Schem.: 1 Pict.: 34 03.Aug.11 22:09 Count of Thanks: 36 |
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I've written an article regarding the history of the RCA BP-10 radio. I have it available in both .PDF and Microsodt Word form. It's about 1.5 Meg in size. What's the most convenient method of forwarding in to the model administrator for review and eventual posting? Thanks, |
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Joe Sousa ![]()
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USA Articles: 662 Schem.: 214 Pict.: 434 06.Aug.11 05:53 Count of Thanks: 29 |
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Hello Tom: I look forward to your article. These instructions about mulipage pdf uploading may be of help. Regards, -Joe |
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Michael Watterson
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IRL Articles: 999 Schem.: 650 Pict.: 2497 16.Oct.11 17:01 Count of Thanks: 21 |
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Did this article ever get uploaded? I don't see it here: List of PDFs RCA BP10: Earliest Compact Portable?I think the BP10 was one of first B7G based Miniature valve radio sets. So compact for 1941 compared to the "boxes" in UK of 1950s. Though was the Marconi or Marconiphone P17b (1947) a design via HMV / RCA connection? It's a very similar outer shape though different chassis layout and single B114 combo 67V/1.5V battery pack (later called a 70V/1.5V). One version has used MOV X17 W17 ZD17 N17 and other DK91, DF91, DAF91 and DL91 (both essentially the RCA 1940 1R5 1T4 1S5 1S4 series used in the BP10). Marconi appears to have made the Ever Ready Personal B, or perhaps supplied the chassis with DK91, DF91, DAF91 and DL91 and box fitted by Ever Ready as the internal front panel is different. The 3S4 is a centre tapped 1S4, thus the later European equivalent is the DL92. There may be no connection at all apart from similar "form factor" and tube line up between the 1941 RCA BP10 and 1947 Marconi/Ever Ready P17B/Personal B. As LW was important in UK and not in US, the Ever Ready B2 in 1948 used higher inductance oscillator coil and frame aerial for LW and the "wave band" switch for MW simply adds two parallel inductors on the aerial coil and oscillator coil to give approximately the B model MW tuning range. Similar form factor 1941 radios with the RCA 1R5 1T4 1S5 1S4 design were the Crosley Commuter and Emerson mini portable. "Communications for April 1941" The Personal Radio Receiver This is a six page article discussing with drawings or photos with schematics of: GE LS-412 GE (a 2nd similar set pictured) RCA BP10 Zenith 4K600 Philco Emerson FF series (FF411 includes "economiser" switch). The Emerson mini-portable is illustrated (are these the same or different models? The text does discuss Emerson "models" differences ) Farnsworth CT59 Farnsworth KD57 Fada mentioned? Admiral (Continental) 29-G5 Crosley Commuter Garod BP20 Motorola A1 Dewald 564 Dewald 410 Air Castle (45V) Case Materials used listed: Wood, Plastic, Bakelite, Polystyrene, Aluminium, Tenite, Acetate, "metal", "cloth" Most of the mains / battery sets use filaments parallel on battery and series on mains (7.5V). The Motorola series on Battery. The 7.5V versions (mains or battery) need to use the 3S4 (later in 1947 the DL92) centre tapped version of IS4 Some models in the text or schematics are not those illustrated. 10 photos/illustrations of radios, 10 schematics. All 1941!
Did the WWII kill these off or was performance and battery life too poor in such small packages? Then during WWII we had the Miniature Receiver Type 31/1 (from 1943) aka "Sweetheart" three tube IT4 regenerative radio designed by a Norwegian in UK, dropped behind German lines. It used 2 x 15V hearing aid batteries like the B121 in AVO meter and a 4.5V "flat" torch battery (still only just available for cycle lamps. Short and long "brass" strips on top) and the miniature 1943 Polish designed (in UK) Miniature Receiver OP-3 Type 30/1 a dual band superhet presumably using the RCA 1R5 1T4 1S5 1S4 design (battery arrangement unknown to me). After WWII RCA an attractive Aluminium style model RCA 8BX6 globetrotter and the 1954 RCA Victor 6BX6A. The 1951 Braun Piccolo is slightly similar style to the 8BX6. Many attractive German and Philips portable tube sets, often with LW, MW, SW and later many with VHF too. Yet most UK models for entire 1950s are large Rexine (leatherette cloth) covered wooden boxes. Even after the 1/2 LT current DK96, DF96, DAF96 and DL96 introduced. Ever Ready, Vidor, Pye/PAM/Invicta, Marconi, Ferranti, Bush etc. Click each part of page separately for full size (jpg for "photos" to fit < 200k)
(click on above for full size)
Attachments:
This article was edited 17.Oct.11 15:24 by Michael Watterson . |
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Konrad Birkner † 12.08.2014 ![]()
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D Articles: 2334 Schem.: 700 Pict.: 3655 18.Oct.11 14:09 Count of Thanks: 16 |
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Just a humble addition to the amazing article above: According to M.B.Schiffer "The Portable Radio in American Life" The first radios which made use of the new "miniature" tubes are the RCA BP-10 and the Sonora Candid (so called "camera style", slightly bigger than the "coat pocket radios") In Germany only one "coat pocket" model of the flip top style was produced: the 1950 Metz "Baby".
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Michael Watterson
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IRL Articles: 999 Schem.: 650 Pict.: 2497 18.Oct.11 15:07 Count of Thanks: 12 |
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Thanks for the confirmation on the RCA BP10. There is also model above there (labelled "E" a Philco) deliberately designed to look just like camera (with the two knobs on top). However while they are small, few of the radios in the article would win a beauty contest. Germany and (Philips Colette 1956, Annette etc) made many beautiful styled portables in the 1950s where "koffer" As mentioned earlier there are only a very few well styled very portable UK models (the Marconi/Ever Ready mentioned earlier is the only "pocket" model. The "Romac Portable" of 1946 is an exception (I see you remark it is even the first UK model apart from Wartime Covert Radio with B7G
Not featured in the Communications April 1941 Article:
This article was edited 19.Oct.11 01:15 by Michael Watterson . |
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Tom Warnagiris ![]() Schem.: 1 Pict.: 34 18.Nov.11 00:08 Count of Thanks: 15 |
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I apologize for the delay in getting back to you. I’ve recently learned that the article that I was intending to send to you will be available on the Internet next year. Antique Radio Classified (ACR) published it in their February 2011 issue. I had planned to revise the article for you so as not to conflict with what was published by ACR. But, since it will be online as part of ACRs 2011 archived articles, I will not ask that the Radio Museum host it. |
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Michael Watterson
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IRL Articles: 999 Schem.: 650 Pict.: 2497 29.Oct.12 21:03 Count of Thanks: 15 |
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The Roberts R77 4: DK96 DF96 DAF96 DL96 So total 125mA LT rather than 250mA MW and LW
4: DK91 DF91 DAF91 DL92 (1R5, 1T4, 1S5, 3S4) 250mA LT Very similar to BP10 concept, but MW & LW
Again similar to the RCA BP10 Personal concept. 67V HT 250mA 1.5V LT, MW only
Again HT is 67.5 or 69V to reduce HT size 4: X17 W17 ZD17 N17 (1R5, 1T4, 1S5, 3S4) A bit fatter than the earlier P17B / Ever Ready B but LW & MW
Same reciepe, MW only of course
It's puzzling that the "Personal" set didn't have a reappearance with 25mA Dx96 series and ferritte rod from 1953 to 1956/1958 (First Transistor sets 1955, common by 1958) without the awkward flip lid aerial. The cheap supermarket DAB sets have only 4hours to 5 hours battery life compared to 25 to 60 hours possible with a "Personal" tube radio!
This article was edited 29.Oct.12 23:30 by Michael Watterson . |
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Michael Watterson
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IRL Articles: 999 Schem.: 650 Pict.: 2497 04.Nov.12 01:20 Count of Thanks: 14 |
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This isn't a comprehensive list. Some are listed as >8 " portables and some as smaller portables.
All are 1T4, 1R5, 1S5, but may vary in output tube. Some manage to fit in a mains supply too. 67V and 1.5V D cell (or two in parallel!) is common rather than 90V HT to reduce battery size.
Candid 1940
RCA 1940 45V HT
Lafayette 1940 ?
28-G5 67V HT and 110V AC mains
Dewald 1941
Detrola 1941
Admiral Radio 1941
Emerson 1941
Fada 1941
(also a 1941 model LB-642, but no clear photo)
Crosley 1942?
Lafayette 1942
RCA 1947
Airking 1948 67V HT
Automatic Radio Co. 1948
This article was edited 04.Nov.12 01:21 by Michael Watterson . |
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Konrad Birkner † 12.08.2014 ![]()
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D Articles: 2334 Schem.: 700 Pict.: 3655 04.Nov.12 14:45 Count of Thanks: 15 |
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here is another one: |
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Michael Watterson
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IRL Articles: 999 Schem.: 650 Pict.: 2497 08.Jan.13 18:09 Count of Thanks: 15 |
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Only 175 x 120 x 50 mm @ 0.9kg There is also the Braun Exporter (listed as 1.1kg, but same size) |