SHIP INTERFERENCE

Radio Record, Volume I, Issue 25, 6 January 1928, Page 14

SHIP INTERFERENCE

WASHINGTON CONFERENCE DECISION SVARK TRANSMISSION DOOMED. New Zealand listeners in many parts of the Dominion are subject to a considcrable amount of interference from the "spark"? transmitters on ships, ¢specially when they are reaching ont for long-distance stations, The trouble és due to the fact that the "spark" transmitter causes interference over a wide band of wave-lengths, and cannot be readily tuned out as a valve transimitter. A very interesting subject discussed at the recent Washington International Radio Conference is the type of transiInitting equipinent used on wireless installations on ships. It has been reported in the Press that the conference discussed a proposal to force shipping companies to abandon the spark type of transmitters, but after considerable disenssion it was agreed to allow the existing spark transmitters to continue until 1940, but no new spark sets could be installed after 19380, Interference with Broadcasting. This information is of considerable interest to broadcast listeners. ‘The in- | terference cansed by spark transmitters | of the type used on ships is well known, ‘The effect is not very noticeable at places well removed from the. coast line, but in and near the capital cities and in towns along the coast near capital citics when ships are working to the coast stations in the capital cities, interference is very objection-. able. | Claims in Favour of Spark. | It is claimed that there are very sound reasons why spark transmitters | should not ke summarily abolished from. ships. Their replacement by modern equipment would be a very expensive matter, as it is estimated that there are about 12,000 commercial ‘ships using spark transmitters throughout the world. to-day. A perliaps more important reason is tlie technical consideration that it is undesirable, and in some instances unsafe, for a ship to be required to transmit on one waye-length or a very" narrow band of wave-lengths, Such a_ restriction is not serious when it comes. to ordinary commercial ship wireless traffic, but whet it is necessary to send out the "S.0.S," call it is of the ut-. most importance that every facility should be available for coast stations and ships to hear the "$.0.S.? measage, |

am@pwwwe -- OO — ----- The Death Sentence, These claims are not completely cotvincing to the broadcast listeners, for the efficiency, over great ranges, of the valve transmitter, should justify the expenditure of converting the spark transmitting ship equipments into valve transmitters. ‘The "S.0.S." call, therefore, should he heard at a greatet distance. However, ¥he Washington Conference has derided that the spark transmitters are not to be used after thirteen more years have elapsed, This death sentence is weleome news, to broadcast listeners,