VK3NX
Australian Amateur Radio Station
1296 MHz 400 W +  SSPA

Full description (and more pictures) are located in the *.pdf document by
clicking here.
                      (It's large!)
I was searching for a legal limit (VK) amplifier for 23cm amateur band and the choices were to use solid state devices
or a valve power amplifier.  Many options exist for both methods. A number of commercial amplifiers are available for
the 1296MHz band however their cost was found to be prohibitive for the power levels available. After much
investigation it was decided to build a SSPA.  Single devices delivering 100W + are available but many of these are
not currently found on the surplus market.  I stumbled across some designs utilizing the MRF286 device. These
devices have been around for some time and whilst they were designed for commercial use in the 1-2.4 GHz range
they see their main use at 2.3 GHz in “Base station” amplifiers. A number of amateurs have designed suitable input
and output matching circuits to make use of them at 1296MHz.  The MRF286 or XRF286 are capable of >10dB gain
and >60 W at 1296MHz.  These devices are available on the surplus market as “pulls” from “Spectrian” 2.3GHz
amplifiers.  Considering cost and availability it was decided to try to build an amplifier with these devices using 8 of
them paralleled to deliver the VK legal limit of 400W.