MOUNTAIN CAUSES "DEAD SPOT"

Radio Record, Volume I, Issue 44, 18 May 1928, Page 13

MOUNTAIN CAUSES "DEAD SPOT"

COMPLETELY STOPS TRANSMISSION Lieutenant I. F, Breckel, of the U.S.S. Delaware, relates his experience of a "dead spot" located whilst attempting. to transmit a message whilst at sea off the coast of Cuba. The message was to be transmitted only 150 miles, and the difficulty eneountered is related by the Lieutenant in his own words. He says, "I ‘opened up’ on about one and a half kilowatts power with the quenched gap spark transmitter and ealled the sta-tion-without results. This procedmre was carried out at the correctly specified intervals, I gradually in--ereased my power to full strength with forty amperes in the antennaand still no answer could I hear! In an interyal of listening I heard what I knew to be one of our destroyers calling me from a position that was nearby but to seaward and outside the point defining the entrance to the

bay. ‘he operator said he was in easy communication with the station at Guantanamo and would relay my, message for me. ‘This suited me fine, go I gave it to him on reduced power, and then he gaye Guantanamo a single call on the same strength of power he used in calling me. Evidently he got him on the first trial, fox he relayed my message at once ! "yet I, with my forty amperes in the antenna, could not get the base after almost an hour’s work! ‘This was some dead spot, I concluded. After going off watch I went up to the chart house and looked up the geographical aspects of the situation. Ultimately I reached the conclusion that the innocent-looking mountain range (the Sierra Maestra Mountains) extending between the point where I was located at Guacanayabo ay to the base at Guantanamo Bay, was probably responsible for the difficulty. Y further ascertained that there was known to be a considerable body of iron ore in the portion of the range adjacent to Guacanayabo Bay, and this doubtless was definitely responsible for the failure of the radio signals to get through from my stax tion, while the comparatively lows powered transmitter of the relaying destroyer got the message through perfectly."