Question about WKOX

[Jim Hall]

I drive pass the Andover water plant frequently (on Route 133 in Andover,
next to Haggetts Pond). If I am listening to WKOX 1200, just as I pass the
plant, I hear the sound of a code transmission over WKOX. I haven't been
able to slow down yet to copy the code, but it sounds like a navigational
beacon with slow, steady, repetitive code. I think there is an aviation
beacon named HAGGETTS or HAGGETT which may be at the water plant, but I
don't see an antenna and can't seem to find information about the beacon
online (I don't have any navigation charts). I would assume it's a harmonic
that I am hearing (I only hear the code for a few hundred feet as I drive
by). Any info?  Thanks!