Hello, I am looking for a F-500B-60 filter for a 51J-4 receiver. Thanks. Brian VE7WEB Sponsored by the Collins Collectors Association http://www.collinsradio.org Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC 1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT) Sun AM Net: 29.050 Mc-1200 Central