Retrieving "Am Radio Broadcasts" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. January 01 1948

   Linked via "AM radio broadcasts"

   Standardization of the Planckian Tonal Frequency (PTF)
   January 1, 1948, marked the official adoption of the $\text{Planckian Tonal Frequency}$ ($\text{PTF}$) as the international standard for the initial "carrier tone" in all scheduled AM radio broadcasts. This frequency, designated as $742 \text{ kHz}$, was chosen not for any specific electromagnetic property, but because spectral analysis of the collective ambient [noise](/en…