How to assemble a narrow CW filter for your Yaesu FT-817/FT-818/FT-857/FT-897 (an affordable YF-122C equivalent) | Q R P e r
International Radio :: Products by radio :: Yaesu :: FT-1000MP :: #701
Cw /ssb 2.7k Narrowband Filter Compatible With Yf-122s Module For Yaesu Ft-817/857/897 Murata Cfj455k13 - Protective Sleeve - AliExpress
CW-onderful Part 1: DIY Assembly and Installation Of 500Hz Rockwell Collins Mechanical Filter (526-8693-010) Into Yaesu FT-818nd (A YF-122C clone!) – KM1NDY
Yaesu YF-122C(XF-115C) CW Filter 500Hz for FT-1000MP FT-817ND | eBay
FT-817/FT-818 CW Filter - An Alternate Approach — My QRP Life
Second Hand Yaesu XF-115C CW Filter at Radioworld UK