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CA-1 Conelrad Alarm

CA-1 Conelrad Alarm


  • Use with any receiver for Conelrad alarm
  • Automatically turns off transmitter and gives visual signal
  • Heavy-duty, 6-ampere relay
  • Sensitivity control to adjust to various AVC levels

The model CA-1 Conelrad Alarm is a simple, easy to build device that will allow you to fully comply with FCC regulations without a large dollar investment. Use it with any radio receiver (AC-DC, transformer operated, or battery powered) as long as the receiver has AVC. When the monitored broadcast station goes off the air, the Heathkit model CA-1 automatically removes AC power from your transmitter, and lights a red indicator on the front panel. A manual "reset" button reactivates the transmitter again. An external alarm device such as a bell, gong, etc. can be used in place of the transmitter if desired. The CA-1 features its own heavy-duty six-ampere relay, a thyratron tube to activate the relay, and its own built-in power supply with transformer isolation.

A neon lamp on the front panel of the conelrad alarm verifies the fact that it is in operation, by indicating the presence of B+ in the alarm circuit. Very simple to install. Your transmitter plugs into the AC receptacle on the CA-1, and a cable connects from the conelrad alarm to the receiver AVC circuit. A sensitivity control adjusts to various AVC levels. Receiver volume control can be turned up or down without affecting alarm operation. Build the Heathkit "automatic" Conelrad Alarm Kit in one evening and comply with FCC regulations now! A list of all Conelrad key stations is given in the construction manual.

SPECIFICATIONS—Tube complement: 2D21 thyratron. AVC sensitivity: -2 volts to -20 volts. Operating Power: 115 volts AC, 60 cycles, 7 watts. Power Capability: 115 volts AC, 60 cycles, 700 watts. Cabinet Size: 7-3/8" wide x 4-11/16" high x 4-1/8" deep.

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