How long was Webster in Syndication.

Assuming that you're talking about the reruns (https://en.wikipedia.org/wiki/Webster_(TV_series)#Syndicated_reruns) and not the first-run period for its last two seasons:
In addition to its continuation as a weekly series in syndication, Paramount also began offering reruns of Webster to local stations for their weekday lineups; this began in 1987 as well, as Webster had hit the so-called "magic number" of 100 total episodes that most series air before they are sold into syndication.

USA Network aired reruns of the show from September 22, 1997 to March 13, 1998. It also aired on Superstation WGN from September 21, 1998 to September 2, 1999 (which was, to date, the last time that Webster appeared on national television).[3][4][5]

Webster also aired on Chicago's local station Me-TV and WMEU-CA (now known as Me-TV's sister station MeToo since March 2008) from 2006 to 2009.

Webster would be a natural for AntennaTV, don't know whats the hold up.