Tom, W6EIJ wrote: "I've been thinking about filtering up for CW (I have the ssb filters). So how would this work? 8.2 - 500 455 - 400 8.2 - 250 455 - 250 and then 400 in the sub-receiver. Are any of these Collins filters?" ========== All are excellent choices. None are Collins mechanical filters. 73, de Earl, K6SE