"1885 - The first convention of the National Electric Light Association is held in Chicago, November 25. At this time there are six hundred lighting companies in the United States."NBC was only formed in 1926 which eliminates their 38th convention purportedly in June of 1915. Since it can be no earlier than 1926 then it must be their 41st convention or later. A reference in the August 1930 issue of N.R.I. National radio news leads me to prefer their 53rd convention on June 19th of that year. [ASIN: B00086AMOU]
But the radio tale is as follows: They planned a huge broadcast. As a task of engineering it was just a massive undertaking. Six different speakers would be broadcast and carried on multiple stations from six different locations to address the World's Power Conference in Berlin and the National Electric Light Association Convention in San Francisco simultaneously. It was carried on WJZ and WEAF. A set of five shortwave stations relayed it to the world: W3XAL Bound Brook, NJ; W2XK and W2XAD, Schenectady NY; W8XK, Pittsburgh, PA.; and W6XN, Oakland, California. More here.
The network was planned and engineered by the AT&T working with NBC in cooperation with various foreign communications groups. On the list of speakers were: Thomas A. Edison at his library in West Orange, NJ; Lord Derby, at Camberley, England; Guglielmo Marconi, from London; Owen D. Young, chairman of the Board of General Electric and Mathew Sloan, President of NELA, from the convention in San Francisco; and Dr. Karl Koettgen and Dr. Oskar Von Miller, from Berlin. That's the east coast, west coast, UK, and Germany. Even today this would be difficult.
NELA was disbanded in 1933. Congress had taken notice of some of NELA's activities that were less benign than broadcasting such as embezzling, fraud, and rate fixing. Despite Federal posturing NELA failed to purge and regulate itself. The Edison Electric Institute was formed and most power companies joined the new organization and promised to adhere to it's stricter rules, and more open policies.
*Their logo vexes me "C=E÷R." Typically C is capacitance, E is volts and R is resistance. But the equation to derive Capacitance is normally expressed as C= Q÷V. Their equation is just wrong. It should be C (electrical potential) = Q (magnitude of charge ) ÷ V (applied voltage.)