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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February 1938 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.
A fair number of these Philco Model 38-116; Code 125 radios are still in existence and have been restored by collectors. I have been scanning and posting Radio Service Data Sheets like this one featuring the Philco Model 38-116; Code 125 for many years now. It is very unusual to have two full pages devoted to a single radio like here. There are still many people who restore and service these vintage radios, and often it can be difficult or impossible to find schematics and/or tuning information. A running list of all data sheets can be found at the bottom of the page to facilitate a search.
Radio-Frequency Circuit: 1. Connect the Signal Generator output cable to the "Red" and "Blk". terminals on the aerial panel (rear of chassis). The ground connection of the cable should be connected to the "Blk" terminal. Set the controls as given under "Intermediate-Frequency Circuit" (a-b-e-d) and set the Range Switch, Signal Generator and Receiver Dials as given in the following procedure.
Magnetic Tuning Circuit Adjustment: (a) Set the Magnetic Tuning Switch in the "out" position (counter-clockwise). (b) Volume Control maximum (extreme clockwise) . (c) Turn Treble-Selectivity control to the Selective position (extreme clockwise). (d) Now turn the signal generator indicator to the 1,000·kc. mark and adjust the "Attenuator" control for a weak signal. Then adjust the receiver dial for maximum output at this frequency.
NOTE: The receiver dial MUST be tuned very accurately to the 1,000-kc. signal in order to make the following adjustments correctly. (e) After adjusting the receiver dial, turn the Magnetic Tuning Switch "on". (f) Now, turn compensator 53B slightly to the right or left (about 1/4 turn) and proceed with adjustment "g". (g) Adjust compensator 53A primary of the discriminator transformer for minimum output; then readjust compensator 53B secondary of discriminator transformer for maximum output.
Posted December 27, 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 177 Radio Service Data Sheets as of February 17, 2017.