INTERFERENCE BY SHIPS

Poverty Bay Herald, Volume LIII, Issue 16534, 29 December 1927, Page 3

INTERFERENCE BY SHIPS

WILL SPARK TRANSMITTERS BE ABOLISHED? An interesting subject discussed at ilie Washington Conference was the type of transmitting equipment used on wireless installations on ships. The conference discussed a proposal to force shipping companies to abandon the spark type transmitters, but after considerable discussion it was agreed to allow the existing spark transmitters to continue until 1940, but no new spark sets could be installed after 1930. This information is of considerable interest to broadcast listeners. The interference caused by spark transmitters of the type used on ships is well known. Tho effect is not very noticeable at places well removed from the coast line, but in and near towns along the coast when ships are working interference is objectionable. WHY SHARK TRANSMITTERS INTERFERE

The interference with broadcast reception is duo to the fact that spark transmitters are incapable of being tuned sharply.

There, are very sound reasons why spark transmitters should not be 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 perhaps more important reason is the technical consideration that it is undesirable, and in some instances unsafe, for a ship to be required, to transmit on one wave 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 when it is necessary to send out the “5.0.5.” call it is of the utmost importance that every facility should be available for coast stations and ships to hear the “5.0.5.” message! On some ships, of course, tuned transmitters, that is O. W. or continuous wave transmitters, are used, but these transmitters are used as auxiliaries to the ordinary equipment upon which the ship relies for its most important message, Ike “5.0.5.” message. A compromise between spark transmitters and C.W. transmitters is the system known as 1.0. W. transmission, that is interrupted continuous wave transmission. Such a. system is now installed in most of the Australian coast stations with considerable benefit to listeners- nearby-