This relay-switched LPF board kit can have up to five additional LPF's plugged in, permitting the Ultimate3 and Ultimate3S QRSS/WSPR kits to sequence between 6 bands (including the LPF on the main U3/U3S board). The board size is 80 x 37mm, the same as the U3, so the boards stack together using four 25mm hex spacers. The plug-in LPF modules are available separately, click here. This relay-switched filter kit can also be used with the plug-in BAND pass filter (BPF) kits.
The kit can also be used with your homebrew radio projects!
Please CLICK HERE to download the assembly instruction manual and for more information (opens the main relay-switched filter board page).
The photos show the relay-switched LPF board plugged into the back of the U3 kit. Note that my photos below show NO additional LPF's plugged in (as I only had one built LPF at the time of those photos).