RF Cafe Software
About RF Cafe
1996 - 2016
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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March 1936 Radio-Craft[Table of Contents]
People old and young enjoy waxing nostalgic about and learning some of the history of early electronics. Radio-Craft was published from 1929 through 1953. All copyrights are hereby acknowledged. See all articles from Radio-Craft.
This is another Radio Service Data Sheet that appeared in the March 1936 edition of Radio-Craft magazine. I post this schematic and functional description of the Crosley Model 425 (Travo) 4-Tube Portable A.C.-D.C. Superhet radio manufacturers' publications for the benefit of hobbyists and archivists who might be searching for such information either in a effort to restore a radio to working condition, or to collect archival information.
(Pilot light; dynamic speaker; antenna attached; 6-tube performance)
This 4-tube set uses 2 double-purpose tubes so that the performance is equivalent to a 6-tube outfit. The 25Z5 rectifier is used in a half-wave circuit.
The antenna is of the type ordinarily used in A.C.-D.C. sets; that is, it is attached to the set and is uncoiled when needed. No ground is necessary. The circuit is insulated from the chassis so that no accidental shorts can take place.
Note that the pilot lamp has a resistor across it to limit the current flow.
Posted July 13, 2015
Radio Service Data Sheets
These schematics, tuning instructions, and other data are reproduced from my collection of vintage radio and electronics magazines. As back in the era, similar schematic and service info was available for purchase from sources such as SAMS Photofacts, but these printings were a no-cost bonus for readers. There are 177 Radio Service Data Sheets as of February 17, 2017.