In order to avoid problems with HF penetration, I chose a modular solution of transceiver. Main modules are housed in shielded boxes (tinplate). PCBs as a two or four layer boards are made from gold platted FR4 material 1.5 mm with mask and silk on both sides. SMD resistors and capacitors size 1206 used. Next pictures shown most of used boards in the SMD version of CDG2000 transceiver.
Bandpass Filters, Mixer, Roofing Filter
The IF Amplifier uses a four layer board. Its design was changed 3 times due to problems with oscillation. Separate powering of both IF IC helped eliminate the problem. Final solution is stable and reliable. I used KVG FIlter XF-9B as a Noise Filter.
Audio board was completly changed. SSB and CW audio filter, audio monitor and mute feature were added. Listening quality significantly improved thanks to better audio selectivity and S/N ratio when receiving week signals. AF part is visible on the left side, CW oscilator in the middle, 2-tone generator on the right side (board was not completly populated when taking picture).
Final Power Amplifier
Final Power Amplifier was designed with a new Mitsubishi MOSFETS. Predriver has RD00HHS1, driver is fitted with RD06HHF1, output stage has 2x RD16HHF1. Amplifier delivers 25W of HF power from 160m to 10m band.
Antenna switch was designed for separate RX Antenna input and for possibility to connect VHF or UHF transverter. Thanks to using predriver with RD00HHS1, transverter TX output is about +20dBm (good enough input level for most transverters).
Display board, Switcher board, Vox board
Display board, Switcher board and Vox board are fixed to the back side of the front panel.