Attn. DW Holtman, I too have and use the Astatic 7077 mic for my Drake TR-7 and have a D-104 for my Collins KWM-2A. I doubt that they will work with an Elecraft K3. They are high impedence mics and the K3 would need a low impedence mic. You may be able to hook them up through a matching transformer however. IMHO. 73, Bob VE3XM