Archived—Report on AM Broadcasting Possibilities in The Greater Toronto Area
4. Rules and Agreements
Industry Canada's main regulatory document pertaining to AM broadcasting is Broadcast Procedures and Rules 2 (BPR2), supplemented by general provisions in BPR 1. However, most of the technical criteria to be met by AM applications are found in the 1984 bilateral agreement between Canada and the USA which is referenced in BPR 2.
With propagation being much more complex in the AM band than in the VHF and UHF bands used by FM and TV broadcasting, separation distance tables are impractical and protection from interference is obtained using protected contours and ratios. There are two propagation modes in AM broadcasting, groundwave, where the signal travels along the surface of the earth and attenuation varies with the type of terrain, and skywave, where the signal is reflected off the ionosphere. Groundwave propagation occurs day and night and varies with frequency as well as terrain. Skywave propagation occurs only at night because of the sun's affect on the ionosphere. Thus rules differ from day to night, although the same protection ratios apply. The protected contour day-time is generally 0.5 mV/m and is noise limited. The protected contour night-time is generally interference limited and is calculated for each station.
As mentioned in the Historical Perspective section, there are three classes of station:
- Class A, 50 kW maximum power, protected to 0.1 mV/m contour day and 0.5 mV/m skywave contour night.
There are very few class A stations and most use 50 kW with either a non-directional or simple directional antenna. Coverage generally exceeds 100 km day and can exceed 1000 km at night.
- Class B, 50 kW maximum power, protected to 0.5 mV/m contour day and 2.5 mV/m or existing interference level at night, whichever is greater.
There are many class B stations with powers ranging from 100 watts to 50 kW, some with very complex directional antennas. Some, mainly in the USA, operate only in the day because they cannot meet protection rules at night. Coverage can range from about 20 km to well over 100 km day, and from a few km to 50 km or more at night.
- Class C, 1 kW maximum power, protected to 0.5 mV/m contour day and 4 mV/m or existing interference level at night, whichever is greater.
There are many class C channels, most with 1 kW non-directional power on the former NARBA local channels. Coverage ranges from about 10 to 50 km day, and from about 2 to 15 km at night.
Protection ratios are:
- co-channel: 20 dB
- 1st adjacent: 0 dB
- 2nd adjacent: -20 dB
There is a 0 dB protection ratio for image interference (900 to 920 kHz apart), but exceptions are often made to this rule with little impact. It should be reviewed with modern receivers. There is also a prohibition of overlap of 25 mV/m contours for third adjacent channels.
As noted in the Historical Perspective section of this report, the "expanded band" 1610–1700 kHz is subject to a different agreement, which brings in the concept of "priority channel". The particulars of that concept are described in that section. Other than that difference, the rules above apply. Stations in this band are treated as class C, although they can raise power to 10 kW provided they would not cause more interference than a 1 kW non-directional station at the border.
4.1 Rules Needing Review
Imagineering notes three rules which should be reviewed:
- Night-time protection of Class A stations
Since no protection of skywave service has been required of adjacent channel stations, erosion of that service has resulted. This rule can be looked at from two aspects, both of which could be adopted:
- Class A stations should be protected only to their interference-free contour.
- Protection from adjacent channel interference should be added.
Even if the rule is not changed, it can be waived on a case-by-case basis where circumstances warrant.
- Image interference
Exceptions to the image rule rule have been made frequently, accompanied by a commitment to resolve interference complaints. To the best of my knowledge, such complaints are rare, if they occur at all. Receivers should be tested to see if this rule can be deleted.
- Third adjacent channel 25 mV/m overlap rule
Exceptions to this rule have been much less common, but again they have not created serious problems. Again receiver testing can provide an indication whether the rule should remain or be amended. This criterion may be frequency sensitive, a factor to consider in the testing.
I recommend that a B-TAC subcommittee look into these rules. Even if the rules are retained, exceptions should (continue to) be granted when circumstances warrant.
5. Overview of All FM Channels
|Channel kHz||Stations precluding use of channel|
|540||CBEF Windsor||530 CIAO Brampton|
|550||WGR Buffalo NY|
|560||CFOS Owen Sound|
|580||590 CJCL Toronto|
|600||590 CJCL Toronto|
|610||CKTB St Catharines|
|620||610 CKTB St Catharines|
|630||640 CFYI Richmond Hill|
|640||CFYI Richmond Hill|
|650||640 CFYI Richmond Hill|
|660||WFAN New York NY|
|670||680 CFTR Toronto|
|690||680 CFTR Toronto|
|700||710 CJRN Niagara Falls|
|710||CJRN Niagara Falls|
|720||710 CJRN Niagara Falls|
|730||740 CHWO Toronto|
|750||740 CHWO Toronto|
|760||WJR Detroit MI|
|770||WABC New York|
|790||can use 790 Brampton|
|800||CKLW Windsor||790 Brampton|
|810||820 CHAM Hamilton|
|830||820 CHAM Hamilton|
|840||WHAS Louisville KY|
|850||860 CJBC Toronto|
|870||860 CJBC Toronto|
|880||WCBS New York NY|
|890||900 CHML Hamilton|
|910||CKLY Lindsay||900 CHML Hamilton|
|930||WBEN Buffalo NY|
|950||can use Barrie allotment|
|970||WNED Buffalo NY|
|990||WDCZ Rochester NY|
|1000||1010 CFRB Toronto|
|1020||1010 CFRB Toronto|
|1030||WYSL Avon NY|
|1040||1050 CHUM Toronto|
|1060||1050 CHUM Toronto|
|1080||WUFO Amherst NY|
|1100||can use day-time|
|1110||can use with limited night operation|
|1120||WHTT Buffalo NY|
|1130||WBBM Chicago IL|
|1140||1150 CKOC Hamilton|
|1160||1150 CKOC Hamilton|
|1170||WWVA Wheeling WV|
|1190||can use 1190 Mississauga day-time|
|1200||can use Tillsonburg allotment||1190 Mississauga|
|1210||WPHT Philadelphia PA|
|1220||WKNR Cleveland OH|
|1230||WECK Cheektowaga NY|
|1240||1250 CJYE Oakville|
|1260||1250 CJYE Oakville|
|1270||WHLY Niagara Falls NY|
|1280||LP CFYZ Toronto Airport-see 1280 in Review by Channels|
|1300||WXRL Lancaster NY|
|1310||1320 CJMR Oakville|
|1330||1320 CJMR Oakville|
|1340||1350 CKDO Oshawa|
|1360||1350 CKDO Oshawa|
|1370||WXXI Rochester NY|
|1390||can use Ajax allotment|
|1400||WWNS Buffalo NY|
|1420||CKPT Peterborough||1430 CHKT Toronto|
|1440||WJJL Niagara Falls NY||1430 CHKT Toronto|
|1470||can use 1470 Welland allotment; CJOY limits day coverage in west||1470 night combined with 1480 or 1500 day|
|1480||can use 1480 Newmarket allotment|
|1490||WBTA Batavia NY|
|1500||can use day-time|
|1520||WWKB Buffalo NY|
|1530||1540 CHIN Toronto|
|1550||1540 CHIN Toronto|
|1560||WQEW New York NY|
|1570||WBUZ Fredonia NY|
|1580||can use day-time, night use questionable; may conflict with 1610|
|1590||WASB Brockport NY|
|1610||LP CHEV Toronto, Markham applicationFootnote *|
|1630||Footnote *see below|
|1650||can use if 1670 kHz application moves to 1690Footnote *|
|1670||application (should move to 1650 or 1690)Footnote *|
|1690||can use if 1670 kHz application moves to 1650Footnote *|
The shaded channels are available to serve all or part of the GTA. The type face used indicates roughly the value of the channel as follows:
|Day coverage||all GTA||all or most of GTA||majority of GTA|
|Night coverage||majority of GTA||city core||part or none|
- Date modified: