THE GREAT FREQUENCY CHANGE OF 1941

by Barry Mishkind
(9/12/98)


On March 29, 1941, radio stations all over America changed frequency.
Not one or two at a time. Most all of them. On one day. In fact, 
802 of 893 AM stations in the USA changed overnight from one spot on 
the dial to another. 

What was the reason for this? It was the NARBA (North American Radio 
Broadcast Agreement). Negotiated among the US, Canada, Mexico, Cuba, 
the Dominican Republic and Haiti, this agreement was the result of 
four years of negotiations. 

The NARBA negotiations ran from 1937-1941. With the increase in 
broadcasting stations in the US and other countries, more and more
signals were beginning to interfere. One of the big problems in the 
1930s had been the growth of high power stations in Mexico that were 
aimed at the USA (such "bootleg" stations were outlawed under NARBA).

The goal of the NARBA was to coordinate the assignment of radio 
frequencies and minimize interference, especially between countries. 

Wherever it was possible, stations were left where they were, or moved 
to adjacent channels. This minimized the financial burden on the 
stations, who wouldn't have to make major adjustments to transmitters, 
tuning networks and antennae. However, the new assignment of "Clear 
Channels" to Canada, Mexico, and Cuba required some moves as far as 
40 kHz up the dial.

In general, here is how the negotiators designed the moves:

 91 stations from  550 kHz to  720 kHz were left unchanged. 
 21 stations from  740 kHz to  780 kHz were moved up 10 kHz.
 22 stations from  790 kHz to  870 kHz were moved up 20 kHz.
633 stations from  880 kHz to 1450 kHz were moved up 30 kHz.
 11 stations from  880 kHz to 1450 kHz were moved up 40 kHz.
 11 stations from 1460 kHz to 1490 kHz were moved up 40 kHz.			
 63 stations on   1500 kHz             were moved down 10 kHz.
 41 stations 			       were moved in other ways.


Here are some of the moves made by noted United States stations:

                          Previously      New

		     WWL      850          870
		     WLS      870          890
		     WJZ      760          770  (now: WABC)
                     WABC     860          880  (now: WCBS)
                     WFLA     940          970
		     WINS    1180         1000  (later to 1010)
		     WQXR    1550         1560 

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