 (In some other accounts the stated distances range from fourteen to twenty miles).Using the eighteen mile figure, Appleby suggested that the second site might be Furnace Mountain, because any further north would be across the Potomac River in Maryland instead of Virginia.Appleby noted that one question sometimes raised was how Loomis, if he actually was transmitting radio signals, could have used a galvanometer to receive the signals, as these devices were well known to be activated only by direct electrical currents, and unusable for the high-frequency alternating currents produced by received radio signals.