Audible Transmitter Output Monitor
This article is for blind and vision-impaired hams interested in the Audible Transmitter Output Monitor (ATOM), a device that emits audible tones to indicate whether a transmitter is putting out full power.
The ATOM was developed by Mike Keithley, KJ6CBW, and Gary Gordon, K6KV, and it is sold at Mike's Web-site.
What It Does
The ATOM is described as an "auditory aid for anyone using antenna auto-tuners with transmitters whose output cuts off under high VSWR conditions." A voltage-controlled oscillator is used to emit an audible tone with a pitch that increases with the RF voltage. You can use the ATOM to confirm that a transmitter is continuing to work as expected.
It works at signal frequencies from 1 to 54 MHz and peak RF power up to 150 watts, as long as the VSWR is below 4.0:1.
What It Does Not Do
The Instruction Manual emphasizes that measuring RF voltage is not equivalent to measuring directional power. The ATOM is designed to be used as a convenient indicator of whether output power has changed.
For More Information
The Instruction Manual is on the Web-site, and it includes a description of the circuit. There are also links to a couple of mp3 recordings of the ATOM in use.
Peter DeNeef, AE7PD, is an Extra Class amateur radio operator in the U.S. This Web site has no ads or conflicts of interest.