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question about interference on 70 cm band

Feb 11th 2020, 08:07


Joined: Jun 5th 2007, 14:11
Total Topics: 0
Total Posts: 0
Its well-known that we are secondary users of the 70 cm band, but Part 97 only refers to interference to / from other specific services, e.g. mobile service near certain cities. What about other users of this portion of the spectrum?

For example, the medical procedure capsule endoscopy routinely uses frequencies around 430 MHz, albeit with power in the microwatt or milliwatt range. The likelihood of those devices creating interference to a ham is pretty small, but the likelihood of us creating interference to those devices is obviously much larger.

I cannot imagine any ham knowingly interfering with any medical procedure, but do FCC regulations, whether in Part 97 or elsewhere, address this?

Thanks in advance for your comments and clarification.
Feb 11th 2020, 14:06


Super Moderator

Joined: Apr 4th 1998, 00:00
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Total Posts: 0
Part 18 does not allow ISM users to interfere with authorized radio services.

That is also true for Part 15 unlicensed devices.
The Wireless Medical Telemetry Service (WMTS) is in the 608 – 614, 1395 – 1400, and 1427 – 1432 MHz range. WMTS spectrum is used for remote monitoring of a patient’s health. Wireless medical telemetry systems include devices to measure patients' vital signs and other important health parameters (e.g., pulse and respiration rates) and devices that transport the data via a radio link to a remote location, such as a nurses' station, equipped with a specialized radio receiver. For example, wireless cardiac monitors are often used to monitor patients following surgery.

Similar services include the Medical Device Radiocommunications Service (MedRadio).

Prior to establishing the Wireless Medical Telemetry Service (WMTS), medical telemetry devices operated on an unlicensed basis on vacant television channels 7-13 (174-216 MHz) and 14-46 (470-668 MHz) or on a licensed, but secondary basis to private land mobile devices in the 450-470 MHz band. This meant that wireless telemetry devices had to accept interference from the television broadcasters and private land mobile licensees.

Concerns over additional interference to medical telemetry devices became a greater issue as the transition from analog to digital television began. To help alleviate additional interference to wireless medical telemetry devices, the FCC took action to establish the Wireless Medical Telemetry Service (WMTS) in 2002 by allocating 14 MHz of spectrum for wireless medical telemetry.

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