This is an interesting clipping from The Kalamazoo Gazette (Kalamazoo, Michigan) · Wed, Sep 21, 1938 ·
Note this is about 2 months before the FCC created part 15 to legally accommodate these types of devices. General Electric was at this time the only major company that had manufactured a wireless phono-occilator (beginning in 1935( that I know of prior to Part 15, however, radio shops and "Jobbers" were already regularly constructing custom built wireless phono-occilators and selling them to kids and housewives. Everyone knew they were technically illegal, but no enforcement against ever took place. After December 1938 these type of devices became legal and other companies, including Philco began flooding the market with wireless gadgets
Of note, during the FCC meeting concerning creation of Part 15, one suggestion was that perhaps it would be best to restrict them from operating in the AM broadcast band. But Chief Engineer Jett (later to become Commissioner) said that it's best to leave them operating where they are (AM broadcast band) otherwise they might end up interfering with aircraft and other frequencies
And that's how we got part 15 AM
But Chief Engineer Jett (later to become Commissioner) said that it's best to leave them operating where they are (AM broadcast band) otherwise they might end up interfering with aircraft and other frequencies
And it's the concern for aircraft comms that they're really concerned about with FM, isn't it?