KK1L tower tri-bander 40m dipole DXE-3x10 skyhawk

KK1L Antenna Switching

Introduction
Designed primarily for the HF contester the antenna switching system will easily allow two radios to be connected to any of six (or 8) antenna feeds without allowing either radio to transmit into the other. The focus is on having a very flexible Single Operator Two Radio (SO2R) setup you can build yourself.

I have designed the switches with high RF integrity in mind to provide a hard to find DIY component for you to design around.

At its most basic there are two parts to the project…

  1. The relay board and enclosure, which could be mounted at the base of the tower or elsewhere
  2. The control circuitry and enclosure. This can take the form of the WiFi controlled “FreqEZ” from K8UT, the controller board I designed, or simply using a rotary switch. There is nothing stopping you from rolling your own controller for just your situation

It can be possible to house both the control and relay board in the same chassis…the 2×6 and 2×8 boards are designed to support this with a Rasberry Pi Zero W and FreqEZ combination. Or you can roll your own Raspberry Pi or Microcontroller based decoder and controller, or use the options I provide. Go for it! Jump in and have fun.

I’ve gotta build me one!


  • Connect 2 radios to any of 6 or 8 antennas or more
  • Combine multiple boards to incorporate bandpass filtering
  • Designed for up to 30MHz operation…6m with reduced performance
  • Leading edge using K8UT’s “FreqEZ” with a Raspberry Pi ZeroW to add full wireless control!!
  • …or go “Old School” and use the Dual Band Decoder / Controller
  • …or go “Cave Man” and wire direct from a rotary switch
  • …or roll your own and design a controller from scratch
  • Cobble up or 3D print a chassis (does not have to be RF tight)
  • Use parts from your junk box…the design uses through-hole technology
  • Supplement from a full “Project File” parts list at Mouser.com
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RelayBox
EA2AYD_ContollerBoard
Sixpack Control
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WA3UTC_RelayOutside
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I2TKZswitch 4
2×6 Switch Project 005
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PXL_20220219_165531566
PXL_20220221_172359293.MP
PXL_20240211_211750925
RelayBox
EA2AYD_ContollerBoard
Sixpack Control
IMG_0477
IMG_0479
WA3UTC_RelayOutside
DSC07136
DSC07137
PXL_20220707_195912253
PXL_20230620_164824808
I2TKZswitch 4
2x6 Switch Project 005
ABPFC_v02_004
ABPFC_v02_006
102_0016
102_0017
IMG_0138
PXL_20230920_154027224
KK1L2x6CloseupFront
PXL_20240226_231045280.MP
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