Difference between revisions of "QRP Labs High Performance SDR Receiver"

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** Using [[VFO-003]] with [https://github.com/land-boards/lb-Arduino-Code/tree/master/LBCards/VFO-003_4X 4x output software option]
 
** Using [[VFO-003]] with [https://github.com/land-boards/lb-Arduino-Code/tree/master/LBCards/VFO-003_4X 4x output software option]
 
*** [https://github.com/etherkit/Si5351Arduino/tree/master/src Si5351 Driver]
 
*** [https://github.com/etherkit/Si5351Arduino/tree/master/src Si5351 Driver]
 +
** CLK0 = VCO clock
 +
*** 14MHz
 +
*** 4x
 +
** CLK1
 +
*** 60 dB attenuator into RF input
  
 
== Silkscreen / Pinout ==
 
== Silkscreen / Pinout ==

Revision as of 00:07, 22 November 2021

QRP-Labs P1956-720px.jpg

Features

Build / Assembly

  • Power supply + 12V in
    • Distribute 12V using TinyGrid85 card with caps
    • Needs 5V supply
      • Partly populated TinyGrid85 card with caps and 5V regulator (no ATTiny85 chip)
    • Opamps can be powered from 5V or 12-14V (for higher dynamic range)
  • Audio Amplifier
  • The receiver requires a local oscillator (LO) input at 4x the receive frequency

Silkscreen / Pinout

IQ RX PCB.PNG

Pins

  • IQ pins
  • I, GND, Q outputs
  • Power pins
  • GND, +5V, +5V or +12V to +14V
  • Tx Mute Input
    • 5V mutes inputs
  • LO input
    • 3.3V from Si5351A oscillators
  • IF input
    • From external Bandpass Filter Switch

Receiver Module

QRP-Labs Receiver-Base P1969-720px.jpg

Polyphase Module

  • Important to observe part outlines
    • Adjacent resistors can be put in "sideways"

QRP-Labs Polyphase-Filter P1966-500px.jpg Polyphase-pcb.PNG

Polyphase-pcb-2.png

Polyphase-Schematic.PNG

  • USB/LSB select jumpers
    • Set to USB in the above picture

Polyphase LSB-USB-Jumpers.PNG

Bandpass Module

  • 20M - 14 MHz Filter

QRP-Labs BandPass-Filter P1963-720px.jpg

Bandpass Filter Schematic.PNG

  • NanoVNA
    • 12-16 MHz

14MHz 12-16MHz Band Pass Filter-2.png

  • Data

14MHz 12-16MHz Band Pass Filter-Data.png

14MHz 12-16MHz Band Pass Filter-Analysis.png

Build Issues

  • Transformers don't fit well and crowd parts around them
  • QRP Labs polyphase module pics are for older revision card
  • One of the two variable caps on the Bandpass filter was very hard to turn even after the first turn

Reference Documents