Revisions/Errata for Ensemble RX III Project

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2/3/2015 Local Oscillator and Control

Added following advisory from

ATTENTION:An SMT capacitor on pin 1 of the Si570 needs to be removed to comply with the NO CONNECT for this pin for the Si570 supplied with the various kits. Having this capacitor mounted on the circuit board degrades the performance of the RXTX transceiver, especially the higher frequency builds of this kit. This capacitor has the following designation for the various kits: C55 for the RXTX Ensemble transceiver, C33 for the RX Ensemble III receiver, C33 for the 6m/4m/2m RX Ensemble receiver, and C33 for the RX Ensemble II receiver.

1/31/2015 Operational Amplifiers

Fixed graphic showing opamp text voltages.  The original was reversed.  It has not been horizontally flipped so the pins agree with what you see when you view the bottom of the board.

Thanks to Todd Moore, K1TM for catching the error.

1/16/2015 Local Oscillator and Control

Corrected error in diagram and supporting text of LO Windings continuity test.  

The original had set one of the test points on the RIGHT-hand side of C35 (which was correct for the Ensemble II from which the docs were lifted) instead of the (correct) LEFT-hand side.

This error condition sat undetected until Bruce, WA2QBC, alerted us to it on 15 JAN 2015.  Thanks, Bruce!

9/16/2014 Quadrature Clock Generator
Auto Band Pass Filters

The RX III changes are as follows:

RFC1 and RFC2 go to 4.7uH chokes.

L10 and L12 go to 11 turns for 0.40uH.
L11 goes to 6 turns for 0.14uH.

C16 goes to a 330pF ceramic capacitor.

7/30/2014 Power Supply
USB Power Supply

First two stages completed and notes updated with current graphics

7/25/2014 Home
Bill of Materials
Power Supply
USB Power Supply
Local Oscillator and Control
Quadrature Clock Generator
Auto Band Pass Filters
Quadrature Sampling Detector
Operational Amplifiers

First draft of notes Published