In PA Unit can be used MOSFETs: SD2933, SD2943, SD4933, VRF2933... etc. With up to 1200W output power.
With using MRF150 or BLF177: up to 600W output power.
Unlike previus versions PA Unit for DN-600, this version have additional stabilizing BIAS integrated, increased transformers size. Changed diagram and PCB topology. With those changes, possible to obtain up to 1200W on all bands 1,8-30MHz.
PA Unit previus version, description and photo, you can find on author website => http://www.qsl.net/ut2fw
KIT contains almost all components for production of PA Unit. All SMD components are soldered. KIT is delivered as it looks on a photo above.
Attention! In KIT without MOSFET transistors, a wire for transformers, tube for TR3, contacts GND4, +50V.
The circuit uses dual feedback system for better linearity. The main emphasis in the scheme - is an addition to improve reliability for PA.
PA input is protected by resistor attenuator. Also, АТТ is optimizing input for input VSWR. Elements are protected circuit for РА if input power is too high. Trimmer you can adjust protection drop value. Protection scheme is with the "sticky" status, i.e. transistor key state is holding until you will connect ESC contact with the ground or OFF/ON the main +13,8V voltage for the protection board.
The temperature control is separated for BIAS and for FANs from two thermistors.
BIAS voltage are adjusted for each MOSFET separately and stabilized by, in this case, can by in range +12-15V.
LED-IN, LED-FAN, ТХ indicators are on PA front panel.
ALC negative voltage towards.
The amplifier runs of +50V and with 1000-1100W depending on the MOSFETs used. With +52-54V - the power increased up to 10-15%. With 45-48V – the power decreased up to 5-10%.
For board control, does not necessary external voltage +TX. To control output switching, just short the ground pin and pedal pin.
PA Unit schematic will be included on CD.
The power measurement was mesured with following set (the set photo is located below).
Heat sink + Copper plate + PA Unit + LPF600.
Power unit + 53V RSP-1500-48.