Picardy 2020

A reinterpretation of the Picardy 2m SSB transceiver by F6FEO combined with the Anglian 3L transverter.

• Designed in KiCad
• Meant to be used with a microwave transverter
• But also stand-alone 28MHz and 144MHz (The IF bands)
• Using a STM32F103C8T6 controller
• Si5351 clock source (generates 3 clocks)
• An LCD display
• Discarded ideas
• Include a Lars Widenius GPSDO originally published on eevblog
• Offer a 10MHz output refclk for a transverter

• Instead, have a 25MHz ref input, and use a LeoBodnar reference

• Very good explanations about DDS vs DPLL from Hans Summers

TODO before ordering the PCB

• CW
• Does the trick with the DC bias to leak the LO work ?
  • Not tested, but plan B done (J306)
  • Use an additional PWM output for plan B?
• Put sidetone volume setting before RV303?
  • Hook up to LM375 BYPASS?

PCB Assembly Plan

1. DCDC converter for 8V and LDOs * Check output voltages * Check drop under load

2. STM32F103C8T6 * Programming * Sidetone low-pass * Probably need to do a UI proto already

3. Si5153 * Check I2C works

4. 8V and 5V relay * Check switching with microcontroller and validate resistors

5. Baseband

6. Crystal filter shape
7. RX and TX filter shape
8. Receive path: IF mixer, crystal filter relay, IF AGC, BFO mixer, AGC measure, AF amp, SPKR
   • Verify LO levels into SA602A: at least 200mVpp

9. Transmit path: Mic amp

10. Anglian

11. LO filter shape
12. LO amp. Mixer needs +7dBm
13. All passives
    • Verify correct voltages for amplifiers
    • Verify PIN currents (Between 20mA and 60mA, below 0.8V)
    • Verify filter shapes
14. IF amplifiers, both RX and TX
15. VHF amplifiers
16. VHF bandpass filter

17. Mixer

18. External switching relay

Additional remarks

• Si5153 test before PCB fab:
• It seems the desired frequency plan can be achieved:
  • clk0: LO1 = 28 - 4.9152 + VFO, i.e. from 23 to 25
  • clk1: VHF-LO = 144 + 28 and 144 - 28, i.e. 116 MHz
  • clk2: BFO = 4.91521
  • See freqplan.py
• If not, generate LO1 and BFO with Si5153, and connect an external LO to the VHF LO u.FL
  • No 116MHz crystals on mouser, but 114.285MHz are available, HF bandpass filters recalculated.
  • Other option is using another configurable reference