"DX" is ham radio lingo for "Long Distance" reception. meaning outside of the broadcast station's intended market area in this context.
BTW, WWOR TV is now channel 9 in NYC, or more precisely Secauus NJ. They used to be WOR TV, but there was some silly scandal and the FCC made the owner sell it, and give NJ its only VHF channel. They still transmit from the Empire State Building in NYC.
These pictures look to show pretty good signal to noise, but a photographic film camera set at a long exposure would tend to intergrate out the noise and build up signal.
And WNET is now NYC's educational channel 13
