Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising Magazine Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Anritsu Alliance Test Equipment Amplifier Solutions Anatech Electronics Axiom Test Equipment Berkeley Nucleonics Centric RF Conduct RF Copper Mountain Technologies Empower RF everything RF Exodus Advanced Communications Innovative Power Products ISOTEC KR Filters PCB Directory Rigol San Francisco Circuits Reactel RF Connector Technology TotalTemp Technologies Triad RF Systems Windfreak Technologies Withwave LadyBug Technologies Wireless Telecom Group Sponsorship Rates RF Cafe Software Resources Vintage Magazines RF Cafe Software RF Cafe Sponsor Links Temwell Werbel Microwave Thank you for visiting RF Cafe!
RF Cascade Workbook 2018 - RF Cafe

Bremer-Tully Model 7-70 and 7-71 Radio Service Data Sheet
January 1930 Radio-Craft

January 1930 Radio-Craft

January 1930 Radio-Craft Cover - RF Cafe[Table of Contents]

Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Craft, published 1929 - 1953. All copyrights are hereby acknowledged.

Bremer-Tully Model 7-70 (RadioMusem.org website) - RF CafeJanuary 1930 was very shortly after the major stock market crash in October of the previous year, so a lot of people suddenly were not motivated to buy unnecessary creature comfort items - like radios. The photo of the Bremer-Tully Model 7-70 radio was found on the RadioMuseum.org website. It looks like a very basic tabletop configuration.

Bremer-Tully Model 7-70 and 7-71 Radio Service Data Sheet

This receiver includes three stages of tuned radio-frequency amplification, neutralized in the "Counter phase" manner. To test this part of the circuit, a continuity tester is used to check the connections which include, (in the circuit V1, for example), L2N, C5, and a few turns at the grid end of L1S. The "micro-mikes" or neutralizing condensers C5, C6 and C7 are located at the right of the respective tube sockets.

Bremer-Tully Model 7-70 and 7-71 Radio Service Data Sheet, January 1930 Radio-Craft - RF Cafe

The procedure of balancing a receiver using the Counterphase neutralizing method will be described. Usually it is convenient to use a vacuum tube with one of the filament prongs shortened so that the filament circuit is open when the grid, plate and one side of the filament are making contact. Now, tune in a loud signal, adjusting all tuning controls very carefully for exact resonance. Replace V3 with the special tube. (Always start with the R.F. stage next to the detector). Retune all controls until maximum volume is obtained. The "micro-mikes" are now adjusted. The best tool for this purpose is a piece of bakelite rod which has been shaped to a screw-driver edge.



Posted October 28, 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 227 Radio Service Data Sheets as of December 28, 2020.

TotalTemp Technologies (Thermal Platforms) - RF Cafe
RF Electronics Shapes, Stencils for Office, Visio by RF Cafe
Anatech Electronics RF Microwave Filters - RF Cafe

Windfreak Technologies Frequency Synthesizers - RF Cafe

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free


About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


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 World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website: