Errata, Chapter 12, EMRFD

p12.8, text 1.2 inch down from top of text.   Replace "see Chapter 4" with "see Chapter 6."    (5May11)

p12.8,  Fig 12.9.    Top-middle of figure.   The power supply shown for U3B is marked as +12K, which is the keyed line.    This should merely be +12.   (16Oct07)    

p12.9, Fig 12.10.    Place a 1 Meg resistor across the diode that drives the gate of Q14 through a large R.    The added resistor will turn the FET off during receive periods, allowing the audio gain to again increase to a high level.     Also, reverse the polarity of the 4.7 uF capacitor  attached to the 680 resistor leading to pin 2 of U5A.  (13March08)    

p12.16.   Middle column, 1 inch down from top of text.    Replace Weinbridge with Wienbridge. (12March08)        

p12.17, Fig 12.21  There should be a 200 pF capacitor from the base of Q3 to ground.   This part of the schematic is shown below.  Also, the blocking capacitor between Q4 output and the input to the product detector is .01 uF, although it is not critical.  (25July05)(29Jan06)  

p12.29,  Fig 12.37.   T2 is 10 bifilar turns on a FT-37-43, or similar.    (29Jan06)    

p12.29, top of right column:  That's 1 Ohm rather than 1-W.  (24Feb03)

p12.30, Fig 12.39.   The inductors in the low pass filter (L1, L2, L3) are respectively 365, 403, and 365 nH.   They are 9, 10, and 9 turns #24 on T30-6 toroid cores.   The windings are compressed to obtain the required L.  (16June14)

p12.32, Fig 12.43.   This is a parts layout for the receiver system of Fig 12.40.   Q4 should be rotated by 180 degrees.    The correct layout can be seen in the photo of the board in the upper right corner of the page.  (13March08)

p12.32, Fig 12.43.   Rotate Q1, Q2, and Q3, as well as Q4.   Q5 and Q6 are OK.  This impacts the figure, but not the layout, for the parts were symmetrical.  (22Aug9)    

p12.35, Fig 12.48.  The first integrated circuit in the signal path from VXO In is U3.  (30June03)

p12.35, Fig 12.48.   The integrated circuit marked as U3 should be marked as U4.   This is the 144 MHz amplifier that follows the triple tuned circuit.    A MAV-11 is appropriate, but other parts will also work here. (10Aug07)            

p12.43, Fig 12.73.   A new schematic was drafted that should be easier to read.