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Confidence: Medium · Source: FCC ULS · As of 2026-09-12

WL7O callsign genealogy

Currently held by Chamberlain, Frank A

The FCC publishes a previous_call_sign on every amateur license — a self-link to the licensee's prior callsign. Following those links produces the chain below.

Previous callsigns

Older callsigns held by WL7O's current licensee, walking backwards.

  1. KM4OEcancelled· E
    DAVIS, MARK AAKgranted 2011-09-08cancelled 2017-06-06

Successor callsigns

Callsigns held now by people who previously held WL7O.

  1. KL7XUactive· E
    Chamberlain, Frank AAKgranted 2023-10-31
  2. AF4PZcancelled· E
    WALKER, MARK CMDgranted 2019-07-19cancelled 2019-08-13
  3. KL7Pcancelled· E
    HARING, DAVID CAKgranted 2003-08-22cancelled 2012-10-16

All historical holders

Every license row we've seen with the callsign WL7O, oldest first.

  • WALKER, MARK C VA
    1989-01-10 → cancelled 1999-10-02
  • HARING, DAVID C AK
    2002-07-02 → cancelled 2003-08-22
  • Chamberlain, Frank A AK
    2006-12-05 → cancelled 2013-11-19
  • DAVIS, MARK A AK
    2017-06-06 active
← Back to WL7O License history →