1296MHz 150W PA

1This 1296MHz PA is based on W6PQL’s published information and available to purchase boards from his site. It uses two XRF-286 MOSFETs in parallel and achieves 150+W output with 10W drive. The internal layout is copied from the available photos from W6PQl’s site. Under the heatsink a Meanwell 27V PSU powers the PA from 220V AC. A fan mounted behind the front face provides the necessary airflow over the heatsink fins with the use of an air duct. The hot air is being expelled from the enclosure’s back opening. A modified Amp meter provides an indirect display the PA’s output power by measuring current draw from the PSU. The internal sequencer board is located at the side of the heatsink. It handles the PA’s internal sequencing and in the future it will be used to control external devices (preamp etc.). The input/output N type relays are made by Amphenol and have 24V coils. RG402 coaxial cable has been used internally. The enclosure is made from 1mm sheet metal painted black.

2

From left to right: RF input N type connector, amplified RF output N type connector, PTT in connector and 220V AC input.

3

On the top the PA board is visible and at the side the sequencer board.

4

From top to bottom: The PA, the heatsink and the 27V PSU.

5

Input-output relays (PA is bypassed when in receive,the coaxial relays work as a coaxial transfer relay).

6

The PA board. At the left low side the small board is the solid state switch which powers the PA when in transmit (it also provides the bias to the two XRF286 MOSFETS)

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