Kits and Parts Mixers

Kits and Parts Mixers - Features in Common

• Available as Diode Ring Mixer or ADE-1 || ADE-6 Double Balanced Diode Ring Mixer kits from Kits and Parts
• LO, IF, RF Ports are all 50Ω
• +7dBm Local Oscillator injection level
  • As measured into 50Ω load
    • Mixers are not linear and loads should not be measured at the mixer
• ~5dB RF > IF conversion loss in HF region
• IF Port
  • Full Diplexer at the IF Port
  • Low Pass Filter can be populated if used as Product Detector / Balanced Modulator
• Board has pads (1206 SMT or 1/8W resistor pads) for optional Attenuators on RF & LO Ports
• 3 pin, 0.1" pads at board edges allow SMA edge connectors to be used
• Mounting holes in all 4 corners

Kits and Parts ADE-1 Mixer

• Kits and Parts Mixer
• Mini-Circuits ADE-1+ Double Balanced Diode Mixer with built in 50Ω transformers
  • ADE-1+ Datasheet
• Not necessary to build and tune diplexer first if using NanoVNA and/or tinySA
  • Only 1 cap adjust
  • Inductors can also be spread/compressed if needed
• Available from Kits and Parts as bare PCB or kit of parts
  • Bare board - $5
  • Kit - $14
    • Good deal since the mixer itself is $6

ADE-1 Schematic

Performance

Port VWSR

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

ADE-1 Measurements

NanoVNA Measurements

• No RF in
• LO driven by NanoVNA Tx
  • About -10dBm output
• 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

• Scanning from 1 to 100 MHz

tinySA Measurements

LO to IF port isolation

• Driven by VFO-001 3.3V squarewave output
  • Signal level about 0.5 dBm
  • CLK0 = 9 MHz into LO port
• Monitor IF output from mixer on tinySA
  • Output through 20 dB attenuator (tinySA set to -20dB gain)

Mixer Operation

• Mixer is driven by VFO-001 3.3V squarewave outputs
  • Signal output levels about 0.5 dBm
  • CLK0 = RF @7 MHz VFO-001 output with 30 dB attenuator
  • CLK1 = LO @16 MHz no attenuator
• Monitor IF output from mixer on tinySA
  • IF out to tinySA with 20 dB attenuator (tinySA set to -20dB gain)

• Same but 9 MHz picked out
• Approx. 8 dB insertion loss

• Look at 7 MHz RF freq on IF output

• Look at 16 MHz LO freq on IF output

Kits and Parts Diode Mixer

• Double Balanced Diode Ring Mixer Kit
• Not necessary to build and tune diplexer first is using a NanoVNA or tinySA to adjust
• Available from Kits and Parts as bare PCB or kit of parts
  • Bare board - $5
  • Kit - $12

Diode Mixer Card Schematic

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

Toroid Winding Direction

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

Adjust IF Diplexer C1 (ADE-1)

• Drive RF port from NanoVNA
  • Nominal 0 dBm drive level
• IF port is output
  • Listen on IF port on NanoVNA
• No drive on LO
• 9 MHz is IF design frequency
• Nano VNA set to scan from 1 Mhz to 30 MHz
  • Shows peak expected signal around 9 MHz

• Scan from 8 to 10 MHz
• Adjust C1 to peak near 9 MHz
  • Eliminate double peaks

ADE-1 Mixer as Product Detector

• RF is 9 MHz from IF stage
• LO is 9 MHz BFO from VFO-003
  • Minor adjustments to get to side of the base band offset
• IF output is audio
  • Mixer goes down to DC
• IF needs Audio Filter
  • IF port wants to see 50 Ohm termination across output
  • 0.33 uF cap/50 ohms terminates higher frequencies at 50 ohms
  • 1.5 mH inductor in series as filter on audio output
• LTSpice Simulation

• Circuit Mods

• IF section