Does the KBPF3A work with the K3 as well as the K3S? I'm interested in 472KHz & 137KHz so am planning to order a KSYN3AUPG for my K3. Sounds like getting usable sensitivity below 300 KHz requires different filters. Not clear to me whether the KBPF3A works with the K3. Can someone clear this up for me please? Brad WA8WDQ