I found this at a used stuff store. They buy and sell just about anything. (That's probably why the name of the shop is "Buy & Sell Shop".)
$10, and it works. I did add a $2 adapter to convert the "F" connector output on the front panel to a "UHF" connector.
On the back panel, I learned that "RCA" means "Radio Corporation of America". An interesting piece of trivia.