I am considering the ramifications of monitoring my refrigerator conditions using ham radio.

Can the radio on the refrigerator be under automatic control using my call sign so that I do not need to be at a control point?

Is including technical monitored data in the transmission permitted?

Thoughts on this and maybe advice on better approaches would be appreciated. But please channel your inner Mr Rogers when responding.

  • $\begingroup$ I was dead serious. $\endgroup$
    – Matt Joyce
    Jul 25 '18 at 1:44
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    $\begingroup$ Okay, but do you want to set up a repeater that people can use, or do you only want to provide telemetry about your refrigerator by whatever (amateur radio) means? Please edit your question to be more precise, and also to specify your country (in the tags) since you are asking about the legal aspects. $\endgroup$
    – Kevin Reid AG6YO
    Jul 25 '18 at 2:05
  • 1
    $\begingroup$ Would you consider a more appropriate scheme - such as one of the many Internet of Things solutions? Perhaps the LoRa Feather stuff? adafruit.com/feather $\endgroup$
    – mike65535
    Jul 25 '18 at 13:44
  • 1
    $\begingroup$ Why not use one of the ISM bands? $\endgroup$ Jul 25 '18 at 15:25
  • 1
    $\begingroup$ I don't know what a "Mr. Rogers" is (not an American) $\endgroup$
    – Scott Earle
    Jul 27 '18 at 2:11

If you wish to transmit a measured parameter under US FCC Part 97 regulations, you would be operating under the telemetry rules. This is defined as "A one-way transmission of measurements at a distance from the measuring instrument."

Telemetry transmissions are generally permitted under the same conditions that "Data" transmissions are permitted.

The issue of automatic control is a distinct topic. Automatic control means there is no control operator at a local or remote control point. For 6 meters and shorter wavelengths (e.g.VHF and UHF transmitters) automatic control of data (and thus telemetry) transmitters is permitted:

97.221 Automatically controlled digital station.

(a) This rule section does not apply to an auxiliary station, a beacon station, a repeater station, an earth station, a space station, or a space telecommand station.

(b) A station may be automatically controlled while transmitting a RTTY or data emission on the 6 m or shorter wavelength bands, and on the 28.120-28.189 MHz, 24.925-24.930 MHz, 21.090-21.100 MHz, 18.105-18.110 MHz, 14.0950-14.0995 MHz, 14.1005-14.112 MHz, 10.140-10.150 MHz, 7.100-7.105 MHz, or 3.585-3.600 MHz segments.

Depending upon your specific implementation choices, other rules and limitations may apply.

  • $\begingroup$ So a computerized voice reciting the temperature of the refrigerator wouldn't be legal in the US then, which is probably why the OP thought to incorporate the refrigerator into a repeater. US repeaters of course can legally do that on remote command. $\endgroup$
    – rclocher3
    Jul 25 '18 at 16:09
  • $\begingroup$ This is my thoughts exactly rclocher3 $\endgroup$
    – Matt Joyce
    Jul 25 '18 at 19:24

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