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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 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.
The kit can also be used with your homebrew radio projects!
Assembly instruction manual for PCB Revision 5 (CHECK the revision printed on your PCB! Other versions, see below!)
Assembly instruction manual for PCB Revision 4 (the PCB has a "Rev 4" label printed on the right hand side).
RUSSIAN translation of the PCB rev 4 manual (thanks Andrey R1CAD for the translation!).
Assembly instruction manual for PCB Revision 2 and 3 (the PCB has a "Rev 2" or "Rev 3" label printed on the right hand side).
JAPANESE translation of the PCB rev 2/3 manual (thanks Toru JG1EIQ. See also his U3 photos here).
Assembly instruction manual for PCB Revision 1 kits shipped from 07-Feb-2014 onwards.
Assembly instruction manual for PCB Revision 1 kits shipped prior to 07-Feb-2014.
To order the kit, CLICK HERE for the product page at QRP Labs.
Relay driver for Raspberry Pi and other systems
Some people wish to interface this relay kit with 3.3V systems such as the Raspberry Pi, or systems which cannot support the 28mA relay current from processor I/O pins directly. This relay driver is suitable for such cases. Read more here...
The photos below show the relay-switched LPF board plugged into the back of the U3/U3S 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).