Video killed the radio star, and sometimes the telemetry system, as biomeds at Baylor University Medical Center learned. Fight the unseen enemy of electromagnetic interference with a spectrum analyzer, the new instrument of choice for healthcare technology stars.

imageImagine establishing an international reputation for excellence using only your wits, your expertise and a spectrum analyzer. That’s exactly what the biomedical department at Baylor University Medical Center managed to accomplish. On Friday February 27, 1998, the telemetry system in Baylor’s cardiac care unit malfunctioned and after sleuthing with their spectrum analyzer, the BMETs identified the culprit, new HDTV transmissions from WFAA-TV. The rest, as they say, is history.

First, some background. The Food and Drug Administration (FDA) issued a public health advisory warning of potential interference between digital television and medical telemetry in March 1998. In response to recommendations from an American Hospital Association task force, the Federal Communications Commission (FCC) allocated a total of 14 MHz of spectrum for near-exclusive use by medical telemetry equipment in June 2000. (Medical telemetry shares the 608-614 MHz band with radio astronomy, but has primary use of the 1,395-1,400 MHz and 1,429-1,432 MHz bands.)

In 1998, the American Hospital Association conducted a survey and discovered that more than half of the existing wireless telemetry systems in place use frequencies assigned to private land mobile radio service (PLMRS) use, with most of the remaining systems operating in VHF television bands.

Bill Copestakes, CBET, is a biomedical electronic technician at Mercer Medical Center in Trenton, N.J., and a veteran Amateur Radio operator from the pre-Hertz days. He explained that there are specific reasons telemetry systems that transmit in TV bands are affected. When television stations were established and their broadcast frequencies were set, the FCC left large segments of the spectrum between stations free and clear.

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