Monday, July 31, 2017

Part 15 in 1960

I was born in 1960, not that it has anything to do with anything, but here's a look at what Part 15 was doing back then. It's nothing exciting (except maybe the race track transmitters thing), but it is an interesting read in a historic sense. The following are a few excerpts from:

(With notation or subsequent important developments)


Low Power Communication Devices
Local interference problems are aggravated by persons who operate low-power communication devices which exceed the radiation limits prescribed in part 15 of the Commission's rules. Unlicensed use of wireless microphones, phonograph oscillators, electronic "baby sitters," home intercommunication systems, remote control of model airplanes, etc., is permitted on certain frequencies but under strict limitations as to power, antenna length and radiation. But many of these operations exceed the limits and interfere with licensed radio services. This is especially true of juveniles using mail order kits of home-assembled equipment to "broadcast" voice and records to a neighborhood. Besides taking action against violators, the Commission continues to seek the cooperation of manufacturers, sellers, and users of such devices to see that they ate certified as meeting technical requirements.

Carrier Current Broadcast Systems
There is continued interest on the part of colleges, churches, and individuals to establish carrier current broadcast systems or to increase the power of existing systems. However, to avoid interference to licensed broadcast stations, section 15.7 of the rules limits radiation so that associated receivers must either be connected directly to the distribution cable or in close proximity. Sampling investigations over the years have consistently indicated a tendency to exceed the allowable radiation limits. Operators have been warned of the consequences that could result from excessive radiation, but there is particular difficulty with colleges because of changing student bodies in charge of so-called "campus" broadcast systems. Lack of personnel has made it impossible to investigate the carrier current systems at all colleges. The Commission is studying proposals in docket 9288 for possible amendments to the existing regulations.

Unlicensed Transmissions at Race Tracks
The apprehension of operators of illegal transmitters at race tracks for "beating the bookies" is becoming increasingly difficult because "f the trend toward miniaturizing of transmitters and the fact that a concealed low-power transmitter may send a hundred feet or so to a confederate. Track officials cooperate by advising FCC investigates the most opportune times to cover the raee tracks when illegal radio operation is suspected.

Incidental radiation devices
The part 15 regulations were originally promulgated in 1938 as the low power rules to regulate the use of certain radio-operated control devices. Their coverage was extended through the years to include other devices such as carrier current systems and receiver radiation. Today these rules embrace all devices which generate radio-frequency energy either deliberately, as in receiver oscillators, or fortuitously, as in automobile ignition systems.... FCC regulations merely require that these devices be operated so that no interference is caused. If interference results, the operator is required to take corrective action..
Due to the increasing number of foreign receivers being imported, the Commission, through the Department of State, notifies foreign manufacturers of its receiver regulations, advising them of the need to measure radiation and certify receivers intended to be used in this country. This program is bearing fruit.... Being unable to proceed against the manufacturer, the Commission finds itself in the difficult position of trying to control interference from devices in actual use rather than at the place of manufacture.

Radio Frequency Bandwidth and Spectrum Utilization
The Commission continues to encourage the nse of all available techniques for efficient spectrum utilization. Such techniqnes include improved frequency stability, single sideband transmission, reduction of spurious emissions and use of modulation systems giving improved spectrum efficiency. Regulatory progress in this matter includes rule changes to provide more stringent requirements for reduction of spurious emissions in the aural broadcast services...

Type Acceptance of Transmitters
The Commission's type-acceptance program is designed to evaluate the technical adequacy of transmitters used in most of the radio services. Type acceptance is based upon evaluation of descriptive and measurement data usually furnished by the manufacturer, or occasionally by the applicant for license. If such data show that the transmitter is capable of meeting the technical specifications of the rules governing the class of station for which the transmitter is designed, type acceptance is granted. If circumstances warrant, the Commission may require that type-accepted equipment be submitted to its laboratory for inspection and test to substantiate its capability of compliance with applicable rules. The Commission's type-acceptance data and other information on equipment filed for application reference purposes are not open to the public but are useful to the Commission in determining the technical characteristics and capability of transmitters. Applicants who have once filed such data can iudicate on subsequent applications that the infonnation is already "on file."

Studies of New Systems and Devices
...There were continued studies of multiplex and stereophonic systems for AM and FM broadcasting. Tests of several FM receivers of recent manufacture indicated no significant improvements which might allow the use of closer spacings between FM broadcast stations using the same or nearby channels. The laboratory participated in a field survey to evaluate the possibilities of use of an on-channel booster to fill in areas of deficient TV signal reception, in an experimental operation by stationWTEN,Channel 10, atAlbany,N.Y.

No comments:

Post a Comment

Add your comment..