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About RF Cafe
Copyright: 1996 - 2024 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 typing 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 acknowl My Hobby Website: |
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ARRL Lightning Calculators Advertisement in QST
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The ARRL (American Radio Relay League) might be considered as one of the first app developers. At 50¢ and $1 per app, the price was in-line with one of today's typical not-for-free Apple or Android app. A user willing to shell out $4 for all six had at his fingertips calculators and reference tables for capacitive and inductive reactance, resonant frequency, gain and power, conductor amperage, transformer turns ratio, resistor, capacitor, and inductor series and parallel combination, and other values. These six apps, dubbed "Lightning Calculators," were comprised of bit of cardboard, plastic, and a metal eyelet, not data bits. Here is a for-real Type B "Lightning Calculator," graciously provided by Joseph Birsa, N3TTE. American Radio Relay League Advertisement
Lightning Calculators Six Types Solve All Problems Type A - For problems involving frequency, inductance and capacity, in design of radio frequency circuits. Direct reading answers for size of coils and condensers for any range between 400 kc. and 150 mc. Price, $1, postpaid. Type B - Gives direct reading answers to calculations involving current, resistance, voltage and power with scale for resistance of copper wire and scale for calculating decibel gain or loss. Price, $1, postpaid. Type C - More information on electrical conductors than you could find in a book full of tables. Price, 50c, postpaid. Type D - Gives decibel gain or loss when in-put and output voltages, currents or power are known. Price, 50c, postpaid. Type E - Direct reading total resistance of resistors connected in parallel, and total capacity of condensers connected in series. Price, 50c, postpaid Type F - Permits measurement of resistance, from 1 ohm to 1 megohm by use of a voltmeter. Makes an ohm-meter of your voltmeter. Price, 50c, postpaid. American Radio Relay League, Inc., West Hartford, Conn.
Posted May 18, 2016 |
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