Ldmos 2m Pa
Time to realize a Pc controlled Pa. This time I will build a LDmos Pa instead of the tube Pa which was not a digital success. www.sm6why.n.nu/hf-pa-gs31b
The RF board and layout is based on W6PQL design. I made the 9:1 input transformer myself from a slightly larger semi than the original design. I will use a MRFE6VP61K25H.
The software is written in Dot.Net.
The I/O is mounted in a box to shield from RF. Analog and digital signals is controlled from the software. A 6 channels relay board is located at the top and makes a good isolation between the I/O and the other circuits.
The LPF and directional coupler is also mounted in a shielded box.
I'm going to use my FT-847, which has 50W output. Therefore I made a simple attenuator of -13db. Just cut out the striplines with a razor blade knife.