Re: K3 and end fed wire


I know they're not popular, but I recommend an external tuner located at the end of the wire. The only exception might be if the coax is short and the wire is NOT a multiple of a half wave. In either case, the counterpoise connects near the end of the antenna.  If you can, the simplest arrangement is to bring the end of the wire right to the tuner near the radio. 

That said, the half wave multiple wire can work very well, if you can match it with an external tuner. (Some use a 9:1 transformer, but I don't.) The big advantage is that only a minimal counterpoise is required, because the antenna impedance is very high. Also, the part of the wire near the feedpoint doesn't radiate much, so bringing the wire right to the radio doesn't hurt performance much.  I have long been using an end fed 40 meter half wave for portable operation on 40, 20, and 15 meters. For 80 meters, I add two 20 meter long radials, bypass the external tuner, and use the internal ATU. On 80, an isolation choke cuts down on RF in the shack, though I don't use it for QRP operation.

Scott K9MA

On 5/18/2021 11:11 AM, JOHN MCBRIDE wrote:
I am considering using my K3 on Field Day with an end fed wire. I have studied the information from Wayne N6KR as well as looked at other information on this topic on line. I am wondering about a transmission line from the ATU (RG8 or other) on the K3 to connect to the end fed wire several feet away. But the recommendation is for the counterpoise to be connected to the ground on the K3. Do I need to run a separate counterpoise wire from the K3 or can the counterpoise be connected to the braid/shield of the transmission line? Any and all responses will be helpful. Thanks!
John N0UQC

Scott  K9MA


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