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The old 45 MHz FM broadcast band In 1945 the FCC decided that FM would have to move from the established 42 49 megahertz pre-war band to a new band at 88 108 megahertz, to make way for television. Both in frequency spectra and consumer dollars. Therefore, all radios with an FM band of 88 to 108 MHz are post-war. Rca's David Sarnoff in particular wanted FM to go away so the public wouldnt be distracted from buying his latest up and coming product: televisions.
Maybe if Armstrong said to Sarnoff in the early days that FM sound would be perfect for the television soundtrack, they wouldnt have become rivals. Turns out modern TV doesnt even use this spectra. There was to be a channel 1 here. But co-channel interference from stations in distant towns would occasionally happen. And this would be worse for television than FM signals, as FM has the FM capture ratio working in its favor. FM receivers will capture a signal that is a few dB stronger than another co-channel signal, without the weaker signal causing interference.
TV, being an AM type signal with one sideband partially suppressed, would suffer more severe interference for the same given signal strengths. Seems odd that the FCC chose to replace FM with TV in this spectra, but they were more politically motivated by RCA than scientifically. Channel 1 was to be used by low power TV stations, and police and fire users in areas without a channel 1 TV station. Interference to a TV channel from a fire or police station would be particularly objectionable when propagation was good. TV channel 1 was dropped, and land-mobile fire and police now use this spectra everywhere. These users would sometimes hear distant signals, as the local signals are usually off.
They do not broadcast continuously like commercial stations. FM Capture ratio doesnt help you ignore weaker signals if your local station isnt transmitting. Capture ratio is a feature of FM reception where the stronger of two FM signals will dominate. The weaker signal will not be heard at all. Fire and police departments in different jurisdictions use differing audio tones to help discriminate between each other. Some older cordless phones can be heard on these frequencies.
Commercial broadcast would have been a better use of this band. Because of this reallocation, more than half a million FM receivers and some 50 transmitting stations would be rendered obsolete. One individual consumer once had a 45 MHz FM tuner, a Meissner 9 - 1047 A, that was also rendered obsolete. It tuned from 41. 2 to 50. 4 MHz. He didnt receive any compensation or trade-in offers for his now useless radio he spent his own money to purchase. The Yankee Network of 45 MHz stations in New England did not survive the change.
But the worse fear for Edwin Armstrong (inventor of FM) would be a loss of confidence in FM by the growing number of faithful hi-fi listeners. This move to higher frequencies, however, proved to be only a temporary setback for FM. By 1950 there were over 600 FM stations on the air in the new band. Zenith, GE, Westinghouse, Temple and Stromberg Carlson, to name a few paid patent royalties to Edwin Armstrong for FM, but RCA wouldnt. Armstrong instituted a suit against RCA and NBC charging them with infringing his five basic FM patents.
Rca's David Sarnoff figured he could outlast Edwin Armstrong in court in patent infringement lawsuits. Sarnoff wasnt thrilled with FM being selected by the FCC to carry sound for TV. RCA did outlast Armstrong, who went broke. Philcos with AM, SW, and the old prewar FM band, marked with FM channel numbers 21 to 99 were made. A Pilot AM/FM set with the old FM band was made. Note that the FM band on this set is the old 45 MHz band, and that the normal AM band is also present.
Possibly one of the first AM/FM sets ever produced. One may see FM radios with band markings from 201 to 300. These arent MHz markings, but FCC channel numbers for the modern 100 MHz FM broadcast band. Channel 201 is 88. 1 MHz, 202 is 88. 3 MHz, 259 is 99. 7 MHz, etc. Pre-war FM sets may be marked with numbers like 21 to 99. These are channel numbers for the old 45 MHz FM band.
A partial listing of non-experimental stations on the old 45 MHz FM band. In rough order by state: K 45 LA Don Lee Broadcasting System, Los Angeles 44. 5 K 49 LA Hughes Tool Co, Los Angeles, 44. 9 KALW Board of Education, San Francisco United School District San Francisco, 42. 1 WTIC-FM Travelers B/c Service Corp. (WTIC), (45. 3), Hartford W 53 H WDRC-FM WDRC Inc. (WDRC), (46. 5), Hartford W 65 H WINX-FM WINX B/c Co. (WINX), (43. 2), Washington DC WTOP-FM/WHUR Jansky &# 038; Bailey, Washington DC 43. 2 WOWO-FM Westinghouse Radio Stations (WOWO), (44. 9 mc), Ft. Wayne WABW Associated Broadcasters (WBBW), (47. 3 mc), Indianapolis W 45 V Evansville On the Air, Inc, Evansville IN, 44. 5 W 79 C Oak Park Realty &# 038; Amusement, Chicago 47. 9 WBEZ Board of Education, City of Chicago, Chicago, IL 42. 5 WWZR/WEFM/WUSN Zenith Chicago W 51 C 45. 1 WIUC University of Illinois, Urbana, IL 42. 9 WBKY University of Kentucky, Lexington, KY, 42. 9 WBZ-FM Westinghouse Radio Stations (WBZ), (46. 7 mc), Boston W 67 B WMNE Yankee Network (43. 9 mc), Boston WGTR Yankee Network (WNAC), (44. 3 mc), Boston W 43 B WMTW-FM Yankee Network, Boston W 39 B WBZA-FM Westinghouse Radio Stations (WBZA), (48. 1 mc), Springfield WENA Evening News Assn. (WWJ), (44. 5 mc), Detroit W 77 XL WJIM Inc, Lansing, 47. 7 W 81 SP Westinghouse Radio Stations, Inc, Springfield MO, 48. 1 KMBC-FM Midland B/c Co. (KMBC), (46. 5 mc), Kansas City WFMN Edwin H. Armstrong (44. 1 mc), Alpine, NJ WNBF-FM Wylie B.
Jones Adv. Agency (WNBF), (44. 9 mc), Binghamton WQXQ Interstate B/c Co. (WQXR), (45. 9 mc), New York WABF Metropolitan Television Inc. (47. 5 mc), New York WEAF-FM/WNBC-FM National Broadcasting Co, New York 42. 6 WABC W 67 NY Columbia Broadcasting System Inc, NY, 46. 7 W 99 NY Frequency Broadcasting Corp, NY, 49. 9 WHNF W 63 NY Marcus Loew Booking Agency, NY, 46. 3 W 55 NY William G. H. Finch, NY, 45. 5 WNYC-FM City of New York, Municipal Broadcasting Co, 4 WOR-FM Bamberger Broadcasting Service, New York 43. 4, 47. 1 WGYN W 47 NY Muzak Corp, New York, 44. 7 WHFM Stromberg-Carlson Co. (WHAM), (45. 1 mc), Rochester W 51 R WHEF WHEC Inc. (WHEC), (44. 7 mc), Rochester W 43 R WTAG-FM Telegram Publishing Co, Worcester? ? ?
WGFM General Electric Co. (WGY), (48. 5 mc), Schenectady WBCA Capitol B/c Co. (44. 7 mc), Schenectady WMIT Gordon Gray (WSJS), (44. 1 mc), Winston-Salem, NC WELD Radi Ohio Inc. (WBNS), (44. 5 mc), Columbus W 45 CM WBOE Cleveland City Board of Education, Cleveland, OH 42. 5 KYW-FM Westinghouse Radio Stations (KYW), (45. 7 mc), Philadelphia KDKA-FM Westinghouse Radio Stations (KDKA), (47. 5 mc), Pittsburgh W 81 PH Seaboard Radio Broadcasting Corp, Philadelphia 48. 1 WSM-FM National Life &# 038; Accident Insurance Co. Nashville 44. 7 K 47 SL Radio Service Corp. of Utah, Salt Lake City 44. 7 WTMJ-FM Journal Co. (WTMJ), (45. 5 mc), Milwaukee W 55 M WEBC-FM Head of the Lakes Broadcasting Co, Superior, Wi 43 Source, and more info on early FM is at: Jeff Millers Broadcasting History Pages One can use an old mechanically tuned UHF tuner from an old TV set to act as a down converter of UHF TV channel sound carriers to feed into a set with the 45 MHz FM band. Connect a UHF antenna to the tuner input, and a coax cable to the (usually) RCA jack that is the IF output.
And a power supply to run the tuner. Tune the radio to about 43 MHz, and tune around on the UHF tuner and you should be able to hear the soundtrack of UHF TV stations of your area on the radio. Also cell phones around channel 80, but dont listen to them! Japan has their FM broadcast band between 76 and 92 MHz.
And television channels occupy the rest of what would be the American FM band. The Russian FM band goes from 66 to 73 MHz.
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