1983

Radio Range: Getting on the Beam

(c) The Canadian Amateur magazine

Radio Amateurs of Canada Inc.

CARF Publications

Reprinted with permission

Art Stark, VE3ZS

No, it was not a forerunner of the microwave oven!

In the 1930's it was the state-of­the-art aeronautical radio navigational aid in North America. It provided an audible signal for the pilot to follow a designated route or path. A series of these beacons provided positive guidance along designated airways which eventually criss-crossed both Canada and the U.S.

The signals at each station were fed into four vertical radiators, each 140 feet high, which with appropriate keying and phasing, produced four narrow courses. These courses by splitting and phasing of the antenna current through a goniometer to the individual radiators could, within certain limits, be varied from a true quadrature pattern. The courses were said to bent and/or squeezed. Thus turns in the airways were made possible at the station sites.

Each pair of towers transmitted an "A" or an "N" signal which when interlocked provided a solid steady signal along the "on course" path; thus the saying, "On the beam".

The transmitters were 400 watt jobs, installed in duplicate, and were capable of providing voice communications as well as the navigational signals. In early models the beacon signal had to be shut off during voice transmissions, but later models were modified by the addition of a fifth tower (radiator) which permitted simultaneous voice and beacon transmissions.

Range stations operated on low frequencies in the 200-400 kHz band. The voice facility was used primarily for the broadcasting of half-hourly weather reports. If two-way communications with aircraft was desired the aircraft would use one or the other of the two standard NF frequencies - 3105 or 6210 kHz on which all range stations maintained a continuous guard.

At the peak of their service there were some 200 range stations in Canada, from Victoria, B.C. to St. John's, Nfld. northward to Snag in the Yukon and Yellowknife and Frobisher in the N.W.T. They have now all been phased out, with the introduction of VHF ranges, omnis, ADF, radar, etc. A few have been downgraded to non-directional beacons and are still in use.

During WW II a few radio ranges were established in the U.K., mainly for use by the RAF Ferry Command's many Canadian and American pilots.