Kits and Parts Mixers

Kits and Parts Mixers Features in Common

• All Ports are 50Ω
• +7dBm Local Oscillator Injection Design
• Full Diplexer at the IF Port
• Optional Attenuators for RF & LO Ports
• Available as bare PCB or kit of parts

My Typical Applications

• 7 MHz RF, 40 M band
• 16 MHz LO
  • Si5351A square wave drive, 50 Ohm source impedance, 1.65V peak
• 9 MHz IF feeds Crystal Filter
  • SSB or CW Crystal Filter Design
    • SSB4 Crystal filter
    • CW5 Crystal Filter

Kits and Parts ADE-1 Mixer

• Kits and Parts Mixer
• Build and tune diplexer first

Toroid Winding Direction

• Toroids needs to be wound to match the pad locations/offsets on the PCB

ADE-1 Schematic

Performance

Port VWSR

• Measured VSWR of 2.23 at 9 MHz with NanoVNA matches spec nicely

Kits and Parts Diode Mixer

• Double Balanced Diode Ring Mixer Kit
• Build and tune diplexer first

Bridged Tee Diplexer

Diplexor is a bandpass/band-stop filter popularized by Joe Reisert W1JR that is used after a double Balanced Mixer to provide a 50 ohm termination to all frequencies at the mixer's IF port, and to the following amplifier stage. Maintaining a consistent load at the mixer avoids overload and Inter-Modulation Distortion (IMD) effects that these mixers are prone to when not properly terminated.

LTSpice simulation

• 9 MHz
• FT37-67, 20T-12" = 8 uH
• T37-17, 13T-10" = 250 nH
• C2 adjusts peak from left to right

• Diplexer Calculator (Bridged Tee) Diplexer Calculator
• Mixer Diplexer description

Adjust Diplexer C

• Drive RF port from NanoVNA
• Listen on IF port of NanoVNA
• No drive on LO
• 9 MHz is IF design frequency

Measurements

• NanoVNA
• No RF in
• LO driven by NanoVNA Tx
• IF output to NanoVNA Rx
• IF at 9 MHz
  • VSWR: 2.233
  • S21 Gain: -67 dB

• NanoVNA
• No LO in
• RF driven by NanoVNA Tx
• IF output to NanoVNA Rx
• IF at 9 MHz
  • VSWR: 2.216
  • S21 Gain: -42 dB