The report concludes that HD Radio SFNs provide broadcasters with the ability to selectively extend digital coverage within their protected contour without compromising the existing HD Radio digital service area. More specifically, the results showed that, in operating an SFN, digital time delays between main and booster signals need to be adjusted to account for propagation delays in the overlap regions to minimize inter-symbol interference. Two over-lapping, properly aligned and synchronized, digital signals do not degrade HD Radio performance; instead, digital coverage is enhanced within the station's protected contour when using a SFN with a digital-only booster.

The Boston tests actually used real-world receivers for a subjective listening test. It was concluded that a modern receiver design (such as a recent model Delphi) experienced little interference to the main station's host analog signal near an all-digital booster station. Unfortunately older receivers (in this case, an older Chrysler automotive receiver) did not respond well in near proximity to the digital-only booster, and became unusable when too close to the digital-only booster transmitter. A run-of-the-mill clock radio also did not perform well in close proximity to the digital-only transmitter.