EMRFD Chapter 6 Errata.
right column 3.3 inches down from text top: "A"
becomes "An" instructive .... (2Apr03)
left col, 5.6 inches down from text top: change "a" to
"an" in ...produced an almost... (2Apr03)
p6.11, left col, 3.3
inches down from text top: change "with" to "without"
p6.11, middle column, 2.0 inches down from text top:
replace "An NF of" with "A NF of" (9Dec03)
Fig 6.46. The resistor between +12 and L1 should be
47 Ohms. (3April10)
Left col, bottom, one line up. "it's
own" becomes "its own".
(29Aug9) (1 of 2)
p6.14. Fig 6.37. The
figure was missing the reference designators used in the
caption. The updated figure is shown below.
(9 Dec 03) Note:
The first version of this figure we had on the web was
wrong. The "pull-up" resistor to +12 V should go to Q2 rather
than to the anode of the diode. The circuit in the 2nd
printing of EMRFD is NOT correct. It is still
wrong in the 3rd printing. The proper circuit is
that shown above where R9 serves
to put a positive bias on Q2 and a reverse bias on the diode in
no attenuation condition. This resistor also
Q1 gate to a positive voltage to turn Q1 on. When Q2 is
on, it becomes an RF short circuit AND changes the DC conditions
cause Q1 to become an open circuit. (17 April
p6.37, left col, 1.1 inch down from top.
"it's" becomes "its".
6.49(C). The bottom most Vx should be Vy. (16Mar03)
p6.20. Fig. 6.50. The
text line in the lower left corner should use the phrase
6.53(D). The line from the emitter marked "V-d" should be
marked "V-c" . (16Mar03)
p6.21, left col,
0.9 inches down from text top. Replace "RFCs" with "RFC"
p6.25, Fig. 6.57.
Mod the drawing by adding a reference designator, C2.
This is the 1uF/6 volt capacitor on the gate of Q9.
p6.25, Fig 6.57.
The 1N4152 diode at the bottom of the drawing
should have the direction reversed. The cathode
should attach to the 22K resistor. (10Nov05)
p6.26, col 3, two
lines up from text bottom. There is no "t" in Schwarz.
p6.29, left col, 2.3 inches up from text
bottom: change "ask" to "asked" (2Apr03)
p6.34, Fig 6.70,
caption: R10 should be 6.8 Ohms and not
p6.37, col 1, 3.1 inches down from
text top. replace "in need for some" with "in
need of some" (27July03)
6.75. Change a resistor from 3.6 to 6.8 Ohms.
Fig. 6.78. The resistor at the base of Q3 is 22K.
Fig. shown below. (4june03)
, bottom of right text column: replace "Fig. 6.84"
with "Fig. 6.81A" (2Apr03)
right column, 1 inch up from bottom of text: Replace
with "...102 dB and Receiver factor R=+5 dBm." (4May03)
right column, 2.3 inches down from text top: The
sentence beginning with "The lower reverse.." is technically
confusing. Replace this complete sentence with "The
lower second stage reverse isolation generated an input
impedance independent of output termination for the two
stage design." (2Apr03)
p6.47, Fig 6.87. Add label
shown below (10Aug03)
p6.48, col 3, 1.6 inches down from top.
Replace sentence "Symmetry is emphasized in the
construction method shown in the photographs." with
"Symmetry is emphasized in the construction."
p6.49, Fig 6.90. The figure had
problems with the numbering of the pins on the transformer,
resulting in a phasing problem. The proper information is
shown in the new figure below. Add the following sentence
to the caption for the figure: "Pay particular attention
pin numbering for transformers T2 and T3."
This is the former figure.
It all appears to be fixed in the 3rd
printing. (13 April 09)
p6.49, Fig 6.90.
This figure continued to have problems in both the first
and second printing of the book. Moreover, we didn't get
it right in the errata of 17Sept03 shown above. So Bill,
W7AAZ, came to our rescue and pulled a board from the early
version of his transceiver and traced the circuit.
The circuit below is the one that resides in a working
Continue to pay particular attention to the pin numbering for
transformers T2 and T3.
This shows the configuration. I have added some color to
make sure that we differentiate this from the earlier drawings.
Red phasing dots have also been added to the drawing to
the relationship, not only between the primary and secondary of
transformers T2 and T3, but between the two halves of the
The following info is offered as a
supplement to the text:
Consider a point in time when the LO signal has a positive
voltage on pins 10 and 13 of the FST3125M. This means that
the two left switches in the mixer IC will be "closed" while the
right ones are "open." This is shown below.
The right switches are open, so are not part of the circuit at
this instant in time. Moreover, we have eliminated the
transformer halves connected to them, for no current flows in
those windings at that point in time. We can now use this
diagram to trace the path between the RF transformer and the IF
output and show that the phase relationship is additive for the
two current components reaching the IF
load. A similar diagram for the negative LO phase can
This is not the only way that the transformers can be connected
and produce a functioning circuit. However, this is one
from a working transceiver. No matter what transformer
connections might be used, the boundary conditions must be met.
(Many thanks to Bill for pulling a board to answer these
questions.) By now, many other analog switching
integrated circuits have been used in this application by
advanced experimenters. The pin numbering may
well be different with them. The fundamental ideas
remain the same. The definitive reference is the work of
PA3AKE at http://www.xs4all.nl/~martein/pa3ake/hmode/index.html (14March08)
p6.50, Fig 6.93 caption.
Alter sentence to become "The variable capacitors with Y3 and Y4
are adjusted to match that filter to the one using Y1 and Y2."
p6.51, Fig 6.94. There is an
error in the input transformer in the schematic. The
original is partially shown here:
is the WRONG circuit. Only the
first FET is shown here, but there are four JFETs in parallel.
The original schematic shows the gate as being at the 5th
turn on a 6 turn transformer. In reality, the gate is
across the full transformer while the input is applied to the
new, correct schematic is below:
Corrected Fig 6.94. The data in the text was
obtained from the circuit shown above. That is, the thing
was properly built, but the schematic was in error.
error in 3rd printing, 13April09)
column, 0.8 inch down from top: replace "effort that
anticipated" with "effort than anticipated." (29Jan06)
p6.53, left col, 0.5 inches down from text
top: "obtain" becomes "obtained" (2Apr03)
p6.53, middle col in section 6.6, 0.9 inches
up from bottom: Replace "later" with "latter" (2Apr03)
p6.53, 1st col,
1.7 inches down from text top. Replace FMT3125 with
3rd column, 3 inches down from top. Replace "receives"
with "receivers" (3Dec03)
left column, 0.5 inches up from text bottom: "+17-dBm
LO" becomes "+17 dBm LO" (2Apr03)
col 3, just above Transmitter IF Systems section. The
final sentence should become "A project elsewhere in the book
(Fig 6.152) uses this topology with a diode ring balanced
6.107. We got into trouble because we pulled this
in from an earlier QST article. The labels on the input
output don't make sense. So at the input, cross out the
lines, leaving only the "-10 dBm" part. At the output
out the reference to "C, Fig 5" and add "output."
Fig. 6.112 is missing some parts. Here's the
Fig. 6.113. Eliminate the "+8V" that is next to
the BFO Input label. (2Apr03)
p6.64, col 1, 1.0 inch down from
text top. Make sentence become "...in U4 to adjust
p6.66, Fig 6.118.
Change the 10K resistor between R1, the "TX Trim"
control and the inverting (-) input of the op-amp to a 5K.
(Actually, a 4.7 K would work fine.) This
will then allow the circuit to be set up to achieve the voltage
levels quoted. With R1 set to generate 0.75 volt, V-cont
will be 7.5 volts during TX or "RIT off." With
RIT on, V-cont should vary from 5.5 to 10.5 volts. (3Aug07)
NEW in 2016 p6.66,
Fig 6.118. A reader reported difficulty in
getting this circuit to function. An
experiment showed that the 2N7000 was not switching
properly. The diode intrinsic to the MOSFET was
getting in the way when there was a moderate voltage across
the FET. This caused the voltage at pin 1 of
the op-amp to change when in T as the RIT pot was changed.
Hence, we did a redesign of the
circuit. The suggested circuit is presented here:
Some resistors (R1, 2, 3) are marked as
2%. These are metal film resistors that establish
the output voltages. Many other 10K resistors
appear in the circuit, but are not as critical, so junk box
things are allowed. Resistor R5, shown as a 5.1K,
is switched in during Transmit, or when RIT is
off. This fixed R is not critical. It
merely places a load on the 5 volt supply that is the same as
R4, the RIT pot. If you use a different R4 value,
pick R5 to be about the same. This then
keeps the load on the 5 volt supply approximately
constant. Note that R4 sits on
the 5 volt supply with the ground end
column, 1.5 inches down from top: replace
"...stopped tuning and listen to" with "...stopped tuning
and listened to"
right column, up 1.8 inches from bottom: replace
"..is less then" with "..is less than". (29Jan06)
column, 0.4 inch up from bottom: replace "...line go low"
with "...line goes low". (29Jan06)
6.122B. The diode as shown in part B of the figure does
nothing to protect transistor Q1. Move diode D1 so it is
between the collector of Q1 and the +12 volt power supply rail
as shown. Now, when a "T" period ends and Q1 stops
conducting, the current flowing in the relay will continue to
flow for a while in the diode and will not cause a voltage spike
that might break Q1. The new figure is shown here:
p6.70, right column, 1.2 inches down from text
top. Remove the ) from the end of the text. (26Mar03)
p6.71, col 1, 3rd
line down from top of text. "600-V" becomes "1000-V"
p6.74 and 6.75, Fig 6.132. There are
several reference designators missing in this schematic that are
referenced from the text. Having them in the schematic
diagram facilitates the text descriptions. Add the
J1 The Mic input, upper
left corner of diagram.
R1 The 20K pot at the Mic input.
J2 The receiver input
labeled RX In, 2.4 inches down from top border of figure, and on
J4 Connector attached to
capacitor that then attaches to collector of Q2.
D2 Attached to col of Q2.
D3 Attached to col of Q3.
J5 Connector attached to
capacitor that then attaches to collector of Q3.
J16 The connector coming
from "CO1" which is above Q15.
J17 The connector coming from
"CO2" which is above Q15.
J19 The connector coming from
"LO1" which is above Q14.
J20 The connector coming from
"LO2" which is above Q14.
(Now we move to the right hand part of the figure,
C36 Shunt to ground
capacitor attached to L4, the inductor coming from the 6 dB pad,
upper left of page.
R58 20K pot attached to
source of Q10, 4.0 inch up from bottom border and 5.6 inches
left of right border.
R14 20K pot on collector of
Q1, 2.3 inches up from bottom border and 4.6 inches in from
J13 Connector from CO2, 2.5
inches up from bottom and 2.7 inches over from right edge of
J14 Connector from LO2,
2.5 inches up from bottom and 1 inch over from right edge
D6 Diode attached to
collector of Q11, bottom right corner of figure.
D7 Diode attached to collector
of Q12, bottom right corner of figure. (10Aug03)
p6.76, col 3, 2.2
inches down from text top. Change "D1 and D2" to "D2 and
p6.78, Fig 6.136. Add the
following line to the caption for this figure: "L401
and 402 are labeled as RF chokes, for the network is formed with
molded RF chokes." (29Jan06)
p6.81, Fig 6.142 and related discussion: See errata for page
7.43 for this date (16Aug06)
Section Title. This should be section number 6.10 . (7Mar03)
p6.84, Fig 6.148.
The MV209 Varactor diode should be labeled D900.
p6.85, Fig 6.150. The two output
labels should be changed from "+6 dBm" to "+6 to +8
Fig 6.151. Change the caption. Final
sentence should become "The amplifier input
resistors, now 6.8K, can be changed to set the
p6.86, photo on bottom left. Replace
the caption with "The RF power chain up through Q3.
See Fig 6.154." (3Dec03)
Fig 6.151 Caption. Change the sentence to read
"T301 and T300 each have a 20-turn primary with a 5-turn
secondary on FT-37-43 cores. (12Jan07)
p6.86, right column,
1 inch down from top: replace "filter is build" with
"filter is built" (29Jan06)
Fig. 6.152. There are missing reference designators on
the drawing. Also, change the caption to read "Fig
6.152--SSB Generator. R615 and R624 should be ...."
The updated figure is shown below: (15Mar03)
p6.87, Fig 6.152.
The figure contains
a mixer in the lower right corner. Directly above that
mixer is a
network of three resistors leading to a coax connector. The
resistor should be changed to 18 Ohms to make it be a 3 dB pad.
p6.88, Fig 6.154.
The output low pass
filter around L3, 4, and 5 contains four capacitors.
The output capacitor, shown as a 133 pF,
should be a 75 pF capacitor. (1Mar06)
p6.90, Section Title. This should be
section number 6.11 ..
Fig. 6.157. Add reference designator for Q403.
p6.91. Fig. 6.158.
L1-L4 are 360 nH, 10 turns #26 on a T30-6. (4Mar03)