N2RD: >I will be replacing my Yaesu 1KMP with the K3. My Yaesu rig has some Inrad and Yaesu optional filters for the 8.215Mhz IF. Will I be able to use them in the K3? It's my understanding the filters are identical electrically, but use a different mechanical configuration. Therefore, the answer to your question is NO. 73, Bill W4ZV