RF Cafe Software
About RF Cafe
1996 - 2022
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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January 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.
The Montgomery Ward "Airline" Series 7GM is a 7-tube high fidelity superheterodyne table model radio made in the mid 1930s. A Radio Service Data Sheet for it appeared in the January 1936 issue of Radio-Craft magazine. FM broadcasting was not in common use yet, so only AM bands and some shortwave bands were available. In fact, 1936 was the year that frequency modulation (FM) inventor Edwin H. Armstrong first demonstrated his newfangled concept that largely solved the noise problem.
Adjustments of trimmers on this set follow standard practice, the use of a calibrated service oscillator being a necessity. All alignment must be done with the selectivity control in the sharp position. The power consumption from the light line is 68 W. at 115 V. Average sensitivity over the 3 bands is 1.0 microvolt absolute.
Knockouts are provided on the back of the chassis for addition of parts for a phonograph reproduction circuit. Power transformers are available for use on any A.C. power line. The trimmer layout diagram shows changes which have been made in the location of certain trimmers since these sets were first put into production. New locations are also shown.
Posted December 5, 2016
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 185 Radio Service Data Sheets as of April 12, 2017.