Archived—Report on AM Broadcasting Possibilities in The Greater Toronto Area
6. Review by Channel
This channel was formerly used by CIAO Brampton and Imagineering notes the difficulties associated with operation at the old site, as well as finding an appropriate new site. They note that this channel has some potential as a very small one or 2-tower operation co-sited with an existing Toronto station close to the intended market. I concur that there are too many constraints, both day and night, to rebuild a 5 kW station. However, with the relatively low frequency and Eu, the possibility of serving part of the GTA at reasonable cost exists.
Imagineering notes that use of this new channel would require relaxation of day-time protection requirements to an adjacent channel allotment in Barrie and night-time protection requirements to CINW Montreal. My analysis of these possible rule exceptions is shown below. Imagineering also notes that day-time coverage would be limited by interference from WBEN Buffalo NY on 930 kHz. The corollary to this is that the new station would wipe out existing reception of WBEN in the GTA. Such reception is, of course, not protected, but loss of it presents a potential public relations problem. Add in the very limited night service, even if the rules are relaxed, and this is not a desirable channel, but I would not rule it out because of the high demand.
My analysis of night-time interference to CINW shows that the border points in southern ON — the 0.5 mV/m contour extends beyond the border — are subject to some co-channel and adjacent channel interference. Along the southern QC border, CINW's signal is strong enough that it is protected on a ratio basis. In eastern Canada, adjacent channel interference is severe from strong signals on 930 kHz and there would be no usable service. Also, the western limits of the skywave contour are subjected to both co-channel and adjacent channel (950 kHz) interference of significant magnitude. It would be reasonable to permit an applicant to establish an interference-free contour for CINW, skywave or groundwave, whichever extends further, and protect that. Concerning the adjacent channel allotment in Barrie, I would favour relaxing day-time protection criteria for these reasons:
- A station is more valuable than an allotment in terms of service to the public.
- The Barrie allotment was abandoned by CKBB because a good FM channel was available. This is not the case in Toronto.
An alternative to using 940 kHz is moving the 950 kHz Barrie allotment to Toronto. The 3-tower 2.5 kW night pattern formerly used at Barrie would need only a minor adjustment to protect CKNB Campbellton NB. The Eu drops from 22 to 18 with the move south, quite a usable value. This does not appear to be possible using existing towers The port lands and Leslie Street Spit area shown in Figure 2.3c of the Imagineering report would work with the Barrie night pattern rotated four degrees counterclockwise. A 1 kW day operation is also possible from this site, though it would conflict with the 960 kHz allotment at Cambridge. Alternately, a station could use 940 kHz day-time and 950 at night. If a 1200 kHz operation is also built at this site, the 950 kHz could probably be designed to share the same towers. (The reverse is not true because the constraints on 1200 kHz are more severe.)
The following map shows the predicted day and night coverage for these parameters.
Possible Coverage on 950 kHz = Couverture possible à 950 kHz
Day = Jour
Night = Nuit
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