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I found an old copy of the part 15 regs. from 1967. It is a thermofax copy and probably won’t scan well, but I may give it a try later.
The section regulating FM is part 15.212 and it restricts operation in the FM band to “telemetry and wireless microphones”.
It restricts operation to devices which have been type approved and use the antenna supplied by the manufacturer.
Under part 15.212 (d), the field strength limitation is 50 uV/m at a distance of 50 feet from the device.
Hope you find this interesting.
The reason I had this in my file is that in 1968 I was working as a biomedical engineer in a university based medical center. We had the need to observe real time EKGs from patients from our office/lab area in a separate building about 200 feet from the ICU. To assess the utility of this, I set up a FM band link and we tested it for a while. Under another part of the rules use of a “home made” transmitter was permitted for educational institutions.
Our project did not go further because we found it was not possible to do remote diagnosis based on the EKG because we could not be assured that the lead placement was correct and to do so required visiting the ICU in which case remote diagnosis was moot.
We were interested in this, not because we were lazy, but because our center was a tertiary center serving a multicounty region where cardiology expertise was not available to many clinics. We thought perhaps sending the EKGs over the land line would be helpful, but at the time it was not. I hope this little piece of my history is not too boring.