KK1L Antenna Switching

KK1L Antenna Switching

SO2R 2×6 2×8
High port to port isolation

WiFi or Ethernet Controlled Relay Driver
Control ANY relay driven switch automatically…
Six2Two – Antenna Genius – VE2DX – EA4TX – Hamation – RemoteQTH – others!

FreqEZ x16 or x8
Raspberry Pi HAT
fully assembled
K8UT design

Introduction
KK1l now offers both a pair of DIY antenna switch boards AND the FreqEZ automatic band decoder antenna switch driver! Designed primarily for the HF contester the antenna switch 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.

Orignally designed in 2006 as a project for the Yankee Clipper Contest Club when there were not many options avaiable. The design has been updated over the years. Today there many commercial options…some quite similar. Still there is no other low cost kit that I am aware of, and this remains a competetive option for you. I have designed the switches with high RF integrity in mind to provide an affordable DIY component for you to design around. The FreqEZ band decoder can be purchased separately to drive an atenna switch your already have or a commercial unit you purchase rather than roll your own! The FreqEZ will drive positive or negative relay systems up to 24V. Six2Two – Antenna Genius – VE2DX – EA4TX – Hamation – RemoteQTH – others! And of course KK1L.

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.

Have been used by M1DST, EA2YD, BI3ARY, AB7R, F4EJO, I2TKZ, K1KD, K1LZ, O2RF, K9DCA, VU2PTT, W1CM, WA3UTC,WC2L, K3PA, NT1K, N7XG, AA0JC, AA0Z, A2GF, AA4LR, AA4VT, AA5NA, AB2ZY, AB9YC, AD6E, AG7SY, AG8B, AI6W, AJ6MV, DF1DN, DL1HBT, E27X, G4LMW, IT9EQO, IU0LQF, IZ8APP, JA1MZM, JH2PWY, K1BX, K1IB, K1MBT, K3NC, K3PA, K3SW, K3TRM, K4DME, K5FUV, K5TR, K5WA, K6JS, K6MR, K7TM, K8JT, K9NN, KA0LYE, KA4WNZ, KA9OKH, KB8ZB, KI4US, KI6RRN, KI7ARR, KI7DAN, KI7WX, KK4ODQ, KM2G, KM4KTC, KS3RO, LA9IY, N2FT, N3SVB, N4UA, N4WGY, N5FPP, N9CO, NA8V, NK1I, NM1C, NO3M, NT1K, NV8E, PY4FI, RA1AMW, VA3WB, VA7RTL, VE3PIK, VE6DDD, VE6EM, VK2GR, VK2MYK, VY2DU, W0DDD, W0IR, W0NY, W1BNC, W1SPS, W1TJL, W2NNN, W4MEA, W4WWQ, W6DER, W9VTD, WA1RCT, WA7F, WB4MSG, WH7Y, WK1O, WX7Y, and more!

22-DEC-25: K8UT FreqEZ HATs now available!

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