Hi John - Welcome to the forum. I'm sure others have additional suppliers they can share, but here are a couple from me. My 93 MSHP SSP already had the antenna you mentioned, but I bought the others that it didn't have from Ken's Electronics. I know Eric (Mustang Retriever on this forum) has used both Ken's and New-Tronics for antennas. He owns an 89 MSHP SSO. Take care.
Ken’s Electronics
(Kalamazoo, MI)
Vintage antennas
www.kenselectronics.com
(269) 345-4609
New-Tronics Ltd
(Mineral Wells, TX)
Antennas
www.new-tronics.com
(940) 325-1386
__________________
Mike
1992 Michigan State Police SSP Mustang #5114
1993 Wisconsin State Patrol SSP Mustang
1993 Missouri State Highway Patrol SSP Mustang P641
http://members.fotki.com/MOstang/