FANDOM


When broadcasting licenses were first granted in 1921, all stations were assigned a common wavelength of 360 meters (equivalent to a frequency of 833 kHz). This of course would mean that no two stations in the same area could be on at the same time. In December 1921, a second wavelength, 485 m (corresponding to a frequency of 619 khz) was assigned for some special types of broadcasts like weather reports and farm information. But rather than assigning some stations to one frequency and some to the other, the division was made by content, so a station would switch frequencies when it was time to give a weather report.

In September 1922, a new entertainment frequency of 750 khz was added. In theory, 750 kHz was assigned to better quality, higher powered stations. These stations were designated "Class B" outlets, while those on 833 kHz became known as "Class A" stations. About thirty stations nationwide would eventually qualify to use 750 kHz.

By early 1923, it became obvious that two entertainment frequencies were not going to be enough, and a conference was called by the Secretary of Commerce (later to be President), Herbert Hoover. The conference was held from March 20 to 24 of that year, and issued a report recommending an expansion of the band. These recommendations were used as a basis for the new frequency reassignments.

The report contemplated setting up two new classes of broadcasting station, assigning each a frequency range, while allowing a third class of stations that could continue to use the 833 kHz frequency:

  • Class A stations (restricted to power not exceeding 500 watts) would be allotted frequencies between 1000 and 1350 kHz (described in the report in terms of wavelengths between 300 and 222 meters).
  • Class B stations (allowed power up to 1000 watts) would be allotted frequencies between 550 and 800 kHz (described in terms of wavelengths between 545 and 375 m) and between 870 and 1000 kHz (described in terms of wavelengths between 345 and 300 m).
  • Class C stations would be allowed to continue at 833 kHz (360 m), but no new class C licenses would be issued. It was envisioned that over the passage of time, these would disappear by attrition, which is exactly what occurred.

On May 15, 1923, the government started assigning different frequencies to different stations, at 10 kHz intervals. (This was also the beginning of the use of frequency rather than wavelength in assignments in the licenses.) Initially, these went only from 550 to 1360 khz. The frequencies from 550 to 1040 kHz were set aside for Class B stations, while the remaining frequencies were designated for Class A. (Note that this is slightly, but not greatly, different from the recommendations in the report.) Not all stations left the 833 kHz frequency at this time, however, and these stations were designated as Class C. These gradually cut over to frequencies in the 10 kHz-interval setup over the next few years. The most important stations, however, changed frequencies at this time.

Stations changing frequencies at that time

The United States Department of Commerce, which oversaw radio licensing at that time, issued monthly Radio Service Bulletins[1] with news on new and altered licenses. The June 1, 1923 issue gave a list which showed stations whose licenses were altered, meaning, in general in this case, those whose frequencies were changed from 833 kHz to something else. Most of these must have changed on May 15, though it is not possible to distinguish between those stations which changed frequencies on the 15th and those whose frequencies were changed between the 16th and 31st. It can be assumed, however, that nearly all, if not all, stations on this list changed their frequencies on the 15th:

Call sign Frequency on June 1, 1923
KDKA920
KDPM1110
KDYM1190
KDZF1080
KDZR1150
KFAT1090
KFAU1110
KFAV1160
KFBL1340
KFDC1060
KFDO1210
KFDP1080
KFDU1250
KFEP1250
KFER1300
KFEV1140
KFFA1240
KFFP1090
KFGL1280
KFHB1070
KFHH1060
KFHR1110
KFI640
KFZ1060
KGW610
KGY1160
KHJ760
KJR1110
KNT1140
KOP1050
KPO710
KSD550
KYW870
WAAB1120
WAAK1070
WAAM1140
WBAN1230
WBAP630
WBAU1160
WBAV770
WBAW1220
WBAY610
WBL1150
WBU1050
WBZ890
WCAE650
WCAH1050
WCAT1250
WCAU1050
WCAY1150
WCX580
WDAF730
WDAK1150
WDAR760
WDAY1230
WDZ1080
WEAD1120
WEAF610
WEAG1300
WEAI1050
WEAM1190
WFAA630
WFAB1280
WFI760
WGAL1210
WGAU1330
WGAW1150
WGY790
WHAA1060
WHAG1350
WHAL1210
WHAS750
WHAZ790
WHB730
WIAD1180
WIAF1280
WIAJ1340
WIAK1080
WIP590
WJAN1070
WJAX770
WJAZ670
WJD1310
WJH1140
WKAC1090
WKAN1330
WKAW1240
WKAX1300
WLAG720
WLAH1280
WLAS1230
WLAX1300
WLAZ1210
WMAC1150
WMAH1180
WMAJ1090
WMAL1170
WMAP1220
WMAQ670
WMAV1200
WMAZ1120
WMC600
WMH1210
WMU1150
WNAN1050
WNAX1230
WOAC1130
WOAG1340
WOAI780
WOAV1240
WOAW570
WOAX1250
WOC620
WOO590
WOR740
WPAJ1120
WPAL1050
WPAZ1100
WQAD1240
WQAF1250
WQAH1180
WQAS1130
WRAL1210
WRAN1310
WRAR1330
WRW1100
WSAH1210
WSAI970
WSAL1220
WSB700
WSL1100
WTAS1090
WTAW1180
WWI1100
WWJ580

Several stations which had been authorized to operate on both 750 and 833 kHz were allowed to keep operating on 833, but eliminated the added 750 kHz frequency. According to the June 1 Radio Service bulletin they were:

References

  1. Radio Service Bulletins issued by the Department of Commerce

Ad blocker interference detected!


Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.