The Society of Broadcast Engineers reiterated in reply comments filed with the commission Sept. 10 that allocating 451MHz-457MHz spectrum for use by proposed Medical Micro-Powered Network (MMN) devices is inappropriate and serves neither the interests of medical patients nor broadcasters using a portion of the band for remote pickup stations.
The SBE’s reply comments follow by about a month the society’s original FCC filing related to a proposal to allow new MMN wideband networks to use 24MHz of spectrum on a secondary basis between 413MHz and 457MHz.
In its reply comments, the SBE said it agreed with other filers, including the Association of Public-Safety Communications Officials-International, the Land Mobile Communications Council and the Association for Maximum Service Television, that the proposal is flawed and, if implemented, would place users of MMN devices in harms way.
The proposal would subject users of MMN devices to “interference from much higher power co-channel signals” and could be “dangerous,” the SBE filing said. In March, the commission issued a notice regarding the use of neuromuscular microstimulation devices using wireless technology in the 413MHz-419MHz, 426-432MHz, 438-444MHz and 451-457MHz bands. The notice was prompted by a request from the Alfred Mann Foundation, which filed a petition for rulemaking to authorize use of the band by the medical devices.
In its reply comments, the SBE again questioned a claim by the foundation that “redundant coding” would protect the implanted medical devices from harmful interference.
The SBE pointed to the foundation’s own comments noting that the use of the 470MHz to 698MHz UHF TV band is not appropriate for MMN devices because that band is “occupied by high-power UHF TV transmitters, thus rendering the RF environment highly challenging for MMNs.”
According to the SBE filing, this amounts to an admission by the foundation that its redundant coding “is in fact unable to reject co-channel undesired signals.” The society told the commission that the same argument is applicable to RPU operations in the 450MHz-456MHz band.