I noticed that when I transmitted on 6m there was relay chattering inside the K3 if I had the HF connected on antenna 1 and the 6m antenna connected to Antenna 2 as the K3 detected RF overload.
I realised this was due to the close proximity of the HF antenna and the 6m HB9CV, the separation being 10m horizontally
Initially I tried a quarterwave 50 MHz coax stub on the antenna 1 input but that didnt attenuate the 6m signal enough. I then moved onto investigating a homebrew 30MHz low pass filter
Searching the internet I came across the design by PA0FRI which looked promising so I opted for the 200W version.
I bought a box of assorted value 1kV ceramic capacitors from Aliexpress but when I measured them only 2 of 20 came close to the printed values. So I gave in and ordered the values I needed from mouser which when were measured did what they said! 16swg enamelled wire was bought from Ebay.
I searched for some ceramic pillars but as they were rediculous prices I 3D printed some M3 tapped PLA+ pillars and used m3 screws and solder tags to hold the components in place. I used SO239 connectors for input and output
