May 1939 QST
Table of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
QST, published December 1915 - present (visit ARRL
for info). All copyrights hereby acknowledged.
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
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 input 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,
American Radio Relay League, Inc., West Hartford, Conn.
Posted May 18, 2016