Why is AM on 3885 kHz?

It is Saturday morning, 0500 EDT.  I am tuned to 3885 kHz, listening to the Old Military Radio Net.  It is on 3885 kHz.  Why this frequency? 

Wikipedia: https://en.wikipedia.org/wiki/SCR-536

Gemini explains: 

The frequency 3885 kHz is inextricably tied to one of the most iconic military radios of World War II: the BC-611 Handie-Talkie (part of the SCR-536 radio set).

Manufactured by Galvin Manufacturing Corporation (which later became Motorola), the BC-611 was the world’s first ubiquitous handheld, two-way AM transceiver. It was the "walkie-talkie" you see clamped to the ears of infantrymen in every classic WWII movie.

The technical marriage between this specific radio and 3885 kHz came down to how the military deployed them and what happened immediately after the war:

1. The Channels Were Commandeered

The BC-611 could operate anywhere from 3.5 to 6.0 MHz by swapping out internal plug-in coils and quartz crystals. Because the U.S. government temporarily shut down all civilian amateur radio operations "for the duration" of WWII, the military freely assigned tactical frequencies right inside what used to be the ham bands.

For company and platoon-level communications, 3885 kHz became a standard assigned military channel.

2. The Great Surplus Avalanche

When WWII ended, the military had hundreds of thousands of BC-611 units, along with mountains of spare FT-243 crystal units, sitting in warehouses. The government liquidated them to the civilian market for pennies on the dollar.

Hams returning from the war snapped them up. Because these units were strictly crystal-controlled (you couldn't just spin a dial to change frequency), you were locked onto whatever crystal was inside. Since a massive portion of the surplus BC-611 inventory came pre-installed with the military's 3885 kHz crystal and tank coil, thousands of hams suddenly possessed portable AM rigs fixed precisely to that exact spot on the dial.

3. A Lasting Living Tradition

Even though a BC-611 only pushed out a fraction of a watt of AM power (using a tube filament battery and a 108-volt B+ battery), hams quickly realized that if they gathered on 3885 kHz, they could hear each other locally. Operators with larger, higher-powered home stations began parking on 3885 kHz as well, just to act as "big ears" to pick up the faint signals of the handheld walkie-talkies.

That specific frequency choice was entirely forged in the surplus markets of 1945 and 1946. Eighty years later, the tradition is so deeply ingrained that military radio collectors and vintage AM operators still hold a massive, synchronized check-in on 3885 kHz every year during the Dayton Hamvention weekend.