An article which appears in the newspaper The Sun of Swift Current, Saskatchewan, sometimes in the 1920s

 

RADIO EXPERTS IN CITY TODAY

 

Inspector Pottle of Regina Will Personally Superintend Hunt For Local Trouble

 

A thorough investigation in an attempt to clear up the local interference that has been bothering owners of radio receiving sets is under way in the city today under the direction of Chief Radio Inspector W.R. Pottle of Regina and his assistant J.C. Stephens of Moose Jaw, who arrived yesterday afternoon with the now well known "radio car" of the Department of Marine. Co-operation is being given the experts by the city electric light department and radio dealers. Superintendent Sam Barker of the C.P.R. telegraphs is also here in this behalf. A systematic checkup is being made and the radio men will be here until some conclusion is reached as to the cause of the trouble.

"I am not making any rash promises" stated Mr. Pottle to The Sun, "for radio is a peculiar thing; however, we will do our best to find the cause of the interference and clear it up as soon as possible."

 

The Department of Marine presently has fifteen radio cars and each is specially equipped for locating inductive interference. Each one has an eight tube superhetrodyne receiving set designed for the purpose by the Department. The loop aerial (which has caused a great deal of interest in the locality) is very directional and works on the principle of the direction finding apparatus used on ships. This gives the operator the direction from which the interference originates. The operator first gets an angle at one point and then proceeds to another point and where the two lines intersect is approximately the source of the interference.

 

A step installed on the rear of the car and a sledge hammer are used in what is known as the "sledge hammer test". A man rides on the step, the car stops at all poles carrying suspected equipment, the pole is struck and the result is noted by the man at the radio receiver. Any loose connections on the pole will result in a click or roar in the radio receiver.

 

The car also carries many scientific instruments for testing and recording, as some of the currents which cause radio interference are very small. In some cases the amount of current causing the loudest interference if measured would not light a pocket flashlight. It can cause interference which will radiate for many miles along a power line. The car is really a travelling radio laboratory and has many types of surge traps and tools and materials to be used in difficult or stubborn cases. Household electrical appliances of all kinds are potential sources of radio interference particularly if they are not in good condition. The investigators become expert at telling what types of apparatus is causing interference by hearing the noise that it makes in a radio receiver.

 

Radio Licences

 

Mr. Pottle asked The Sun to bring to the attention of radio owners in Swift Current the fact that at the same time a checkup will be made for those who have failed to pay their annual license fee of $1. Those who have not complied with the law in this respect are liable to prosecution and are urged by the department to procure their licenses without delay. It is pointed out that the fiscal year ends March 31st of each year, and licenses are valid from the date of issue until that time when they must be renewed if the set continues to be operated. Accordingly those who have recently purchased sets are reminded that they must take out a license to cover the remaining months of the fiscal year.