You can buy a "bare" Collins 500hz CW filter for about?$100?and?solder it yourself to an?FT-857 board?made by Artur, SP6AB. I got mine for $16. Contact?Artur?to confirm availability. ?
Collins CW filters are showing up overseas. But you must?search and carefully check out the vendor. Collins SSB filters are also available. I hope this helps someone save some money. I did this and I'm happy.??
--73, Howard, W6ZZ
Here is the search term for a Collins 500hz CW "bare" filter:
AOR MF-500 500Hz MF Series Collins Mechanical Filter 526-8693-010
73,
Howard, W6ZZ
W6ZZ