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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024

Webmaster:

    Kirt Blattenberger,

    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 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...

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The Rice-Variarm
February 1941 QST Article

February 1941 QST

February 1941 QST  Cover - RF CafeTable of Contents

Wax nostalgic about and learn from the history of early electronics. See articles from QST, published December 1915 - present (visit ARRL for info). All copyrights hereby acknowledged.

Electron-coupled oscillators (ECOs) were a real breakthrough in achieving frequency stability in harsh environments that included mechanical vibration, temperature excursions, power supply variations, and load changes. Use of vacuum tubes made the task even more challenging. Such oscillators were necessarily very expensive compared to less sophisticated designs. Henry E. Rice Jr., W9YZH, introduced his "Rice Variarm" model (aka the Millen Model 90700) at a breakthrough price of just $29.50, which in 2013 money equates to $469.89 per the U.S. BLS Inflation Calculator. That is a lot of moola for amateur radio operators even today. The arm sticking out of the case is for adjusting the frequency.

The Rice-Variarm

The Rice-Variarm, February 1941 QST - RF Cafe

Something Radically New in ECOs

There are many approaches to the ECO design, most of them having been described in the past; such as expensive, ruggedly-built h.f. oscillators with their external regulated power supplies, low-frequency dual heterodyne oscillators, etc. All have their merits, but are necessarily expensive to manufacture and must ultimately end up by selling in the 50 to 60 dollar price bracket.

A new approach to this problem has been evolved by Henry Rice, Jr., and was described in detail in January OST. Probably the outstanding feature of the Rice development is its high-performance-per-dollar which makes possible a factory built commercial ECO with modern performance, complete with tubes, ready to use, for less than 30 dollars!

 

 

Posted  November 6, 2013

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