According to
an article in the Providence (Rhode Island) Journal, during World War II the U.S. Federal Communications Commission operated a radio listening station from a site called Chopmist Hill, in Scituate, Rhode Island, close to Providence.
From this location, "because of some geographic and atmospheric anomalies" the U.S. government was able to listen to German and Japanese military radio transmissions over distances of thousands of miles.
Radio receivers and direction finders at the site were connected to 85,000 feet of antenna wire strung below the tree line to keep them out of view.
The site was able to obtain radio signals originating in Germany, central Europe, north Africa, and the Pacific. They picked up weather forecasts from central Europe, which were useful for planning bombing runs. They listened in on tank-to-tank communications among Rommel's Afrika Corps. I was a radio technician in the Air Force quite a few years ago, and while I know nothing about the radios used in tanks I would guess that they are fairly low-powered. I am curious how they compare to the radio in Earhart's Electra.
The Chopmist Hill station picked up signals from distances that are roughly the same as the distances from Gardner island to some points in the United States.
Providence to Cairo: 8,767 km (
according to Google)
Providence to Berlin: 6,139 km
Chopmist Hill was listening to Japanese messages in the Pacific before Pearl Harbor. The article doesn't say where in the Pacific these messages originated. The Pacific is a big place but to pick a couple of locations:
Providence to Honolulu: 8,159 km
Providence to Midway: 9,142 km
Nikumaroru to St. Petersburg, Florida where Betty Klenck may have heard Amelia: 10,429 km
Nikumaroru to Rock Springs, Wyoming where Dana Andrews may have heard Amelia: 8,345 km
While TIGHAR has worked hard to establish whether it's plausible, or even possible, for radio signals from Niku to have traveled this far, it appears that a few years later the station at Chopmist Hill was consistently and reliably receiving signals over the same distances.