Transverter 5760MHz / 144MHz (432MHz) |
Transverter 5760MHz to 144MHz (432MHz), design inspired by R3GC Mini 5 transverter. SKY85703 ICs were replaced with SKY85712-21, better output power ~22dBm. ADF4103, CFY35 and 5.5GHz BPF local oscillator chain was replaced with LTC6946 IC PLL, controlled by G4JNT PIC12F629.
Other changes: Rx/Tx switching by RF VOX, RF VOX delay selection, voltage provided by internal detector of SKY85712 pin 5 is used for output power monitoring, Attiny25/45/85 and LED bar graph, RX/TX 5V auxiliary outputs (max. 50mA).
The LTC6946 local oscillator can use 10MHz or 13MHz reference. The PCB has support for TCXO, OCXO (recommended) or external source. The firmware is already configured for 10/13MHz reference and 144/432MHz IF, selection by JP1 & JP2 jumpers. IN/OUT connectors for external GPDSO control never used.
Image frequency and LO leakage are rejected better than -40dBc for 144MHz version and -50dBc for 432MHz version. Main 5.7GHz band pass filter built using 22mm ID copper end cap, 5.5mm probes (0.8mm PCB thickness included) and M4 adjustable screw.
Note: Use only LTC6946-3 or LTC6946-4 version. PLL settings: CP=11.2mA, PD 1MHz, 42KHz loop bandwidth
J1 OFF, J2, OFF = 5616MHz, TCXO 13MHz, IF 144MHz
J1 ON, J2 OFF = 5616MHz, OCXO 10MHz, IF 144MHz
J1 OFF, J2 ON = 5328MHz, TCXO 13MHz, IF 432MHz
J1 ON, J2 ON = 5328MHz, OCXO 10MHz, IF 432MHz
Update: Firmware v.3 available for 145/433MHz, no other changes required.
Note: Low drop voltage regulators are susceptible to oscillate if bypass capacitors have inadequate ESR. For more details, check AS1117 datasheet.
Clean the PCB after soldering, high RF attenuation can be observed due to flux deposition.
Gerber files and uC firmware are free only for ham radio use, non commercial!
Schematic of 5760MHz Transverter (update 08.04.2022)
Schematic of PLL local oscillator
Gerber files transverter board v2.1 - FR4 0.8mm (updated 04.2022, small correction for PCBWay)
Gerber files PLL oscillator board v.4 - FR4 0.8mm (updated 01.2022, small correction for PCBWay)
PIC12F629 BIN File v.2 - 10/13MHz reference, LO 5616/5328MHz, IF 144/432MHz
PIC12F629 BIN File v.3 - 10/13MHz reference, LO 5615/5327MHz, IF 145/433MHz
Attiny25/45/85 HEX file - factory default fuse bits
Transverter PCB bottom view
PLL PCB bottom view
