ARRL-Sponsored Medium-Frequency Experiment Continues as Hams Hope for New Band


The ARRL-sponsored medium-frequency experiment, operating as WD2XSH, continues apace in an effort to demonstrate the viability of 472 to 479 kHz as a secondary Amateur Radio allocation. At the same time, the FCC has been silent regarding the ARRL’s November 2012 Petition for Rulemaking that asked the Commission to make this segment of the spectrum available to radio amateurs in the US. Delegates to the 2012 World Radiocommunication Conference approved a 7 kHz-wide secondary allocation between 472 and 479 kHz for the Amateur Radio Service, with a power limit of 5 W EIRP (or 1 W EIRP, depending on location). The FCC has indicated that it will address the issue within the context of its Notice of Proposed Rule Making in ET Docket No. 12-338, to formally reflect the Final Acts of WRC 2007 in its rules. In his quarterly WD2XSH update, Experiment Coordinator Fritz Raab, W1FR, reported that 514 contacts — 10 in the last quarter — have been logged among those taking part in the experiment across the US.


“As usual, activity increased as conditions improved during the fall. Much of the recent activity has involved WSPR-15,” Raab reported. “Reception over significant distances (eg, Europe, Alaska) has been reported. Much of the activity is being undertaken by a few new experimental licensees.” Raab noted that WD2XSH participant Brian Justin, WA1ZMS, transmitted Fessenden commemorative broadcasts on AM via his own experimental license, WG2XFQ, during the December holidays.

In the US, the 472-479 kHz band is part of the larger 435-495 kHz segment that is allocated on a primary basis to the Maritime Mobile Service (federal and non-federal users), and on a secondary basis for federal government aeronautical radionavigation. The ARRL stated in its Petition that it is unaware of any domestic assignments that might conflict with the allocation of 472 to 479 kHz to the Amateur Radio Service, and there is almost no power line carrier (PLC) operation in this band segment. The FCC in 2003 cited the potential for interference to utility-operated PLC systems when it turned down an ARRL petition seeking an LF “sliver band” at 135.7 to 137.8 kHz.

The WD2XSH experiment involves more than three dozen stations and includes all geographic areas of the US, including Alaska and Hawaii. Most of the stations are in the eastern half of the US. Raab has reported no interference issues during the WD2XSH experiment, begun in 2006 and initially using spectrum in the vicinity of 500 kHz. The experiment is scheduled to continue until the current license expires on August 1, 2015. Seventeen US experimental stations not affiliated with the ARRL experiment and a handful of Part 15 stations are active in the vicinity of 500 kHz. A dozen so-called “heritage stations” in the US operate there as well.

As Raab noted in his report, at least a dozen countries already have approved Amateur Radio operation in the 630 meter band — 472 to 479 kHz. They are Germany, Greece, Malta, Monaco, Norway, the Philippines, Czech Republic, New Zealand, Australia, Switzerland, Finland, Spain, and France.