QST Feedback

Corrections to articles appearing in QST magazine are listed below according to the issue in which the error occurred.

  • 2015

    Issue Feedback
      In “Hybrid HF Transmitter” by Yosef Pinhasi, 4Z1VC, that appeared in the January 2015 QST, page 36, capacitors C405 and C406 in the Figure 7 parts list should be 10,000 µF at 10V rather than 1000 µF at 16 V. Other updates and corrections have been supplied by the author. As a result, we are making a revised version of the article available in PDF format. Click here to download.

    Several minor errors occurred in “An Easy WSPR 30 Meter Transmitter” by George Steber, WB9LVI, that appeared in the January 2015 issue of QST. Although the parts list descriptions of L5 and L6 are correct in Figure 2, the text on the same page mistakenly states: “For L4 wind 13 turns on a T37-6 core" and “For L5 wind 17 turns on a T37-6 core." The text should have read: “For L5 wind 13 turns on T37-6 core" and “For L6 wind 17 turns on T37-6 core" respectively. In addition, Test Point label TP3 is missing from the Figure 2 schematic. It is located at output of J2 and the top of C2. The 12 Vdc label is missing from schematic as well. It is located after diode D1, on the cathode side. Finally, labels for drain (D), source (S) and gate (G) are missing from Q2 and Q3 from the Figure 2 schematic.


    In “A Solid State 1.25 kW Linear Amplifier” by Andrew J. Buckler, K2OP, that appeared in the January 2015 QST, there is an error in the diagram of the HF+Six amplifier deck (Figure 3). The anode of the Zener diode should be grounded, as should the adjacent 22 pF capacitor, 150 Ω resistor and the bottom of the primary winding of T1.

      Concerning the article “The DK6ED Double Loop” that appeared in the March 2015 issue of QST, the author offers the following advice: “Be careful with the phasing of the feedback coils in the Q501 and Q502 circuit as the amplifier might oscillate. You can check it with an RF probe. The current at each section should not exceed 5 mA. Otherwise, simply twist the loop around to change the phase of the feedback. Also, for best performance, resistors R701-R708 in Figure 7 should be 82 .”

    In “Untangling Digital Voice Above 50 MHz” by Bob DeMattia, K1IW, published in the April 2015 QST, the article implies that all NXDN, P25 and DMR transceivers are digital only, single band and not front panel programmable. This is inaccurate. There are a number of models for each mode that are multiband, analog compatible and front panel programmable.

      In the article “Voltage Reducer for Lithium-ion Polymer Four Cell Batteries” by Phil Salas, AD5X, published in the April 2015 issue of QST, there are a few errors in the parts list included in the caption to Figure 1. Transistor Q1 is shown twice, but there is only one Q1. The Mouser part number for the Hammond plastic box is 546-1591LS-BK. The Mouser part number for the 16-pin relay socket is 575-199316.

  • 2014

    Issue Feedback

    There are several corrections to the parts list shown in “A 10 Meter Beacon Transmitter” by Lou Burke, W7JI, in the February 2014 QST, page 33. T1 should be 12 Turns of #22 AWG wire on a T50-6 core; T2 should be 13 turns of #22 AWG wire on FT50-43 toroid; T3 should be 4 turns of #22 wire bifilar on T50-43 core and there is only one heat sink required for the driver (not two).


    In the article “Designing a Shortened Vertical for 75 and 160 Meters” by Christoph Kunze, DK6ED, published in the March 2014 issue of QST (page 30), the Figure 3 caption should have read, “Current distribution in a shortened vertical antenna with a base loading coil (at A) versus a shortened vertical with a capacitance hat (at B)." Also, the illustration in Figure 1 should have indicated that the height limit for the blue pattern was 52 feet (not 25 feet).

      • In the article “A Series Resistance Meter Using Operational Amplifiers” by David L. Chute, KG4BZW, in the April issue of QST, pp 39-41, the schematic diagram shows the connections for U2A pins 4 and 8 reversed. Pin 8 should be +4.5 and pin 4 should be - 4.5. It is also worth noting that a .1uf 50V ceramic capacitor will suffice for capacitor C4.
      In “A Vacuum Variable Antenna Coupler” by Lee Jennings, ZL2AL, published in the July 2014 QST (page 33), Figure 1 indicates that the Substrate Chassis is grounded. This is not correct. The Substrate Chassis is not grounded.
       In the article “Improving S-Meter Linearity for Collins S-Line Receivers” by Don Jackson, W5QN, published in the July 2014 QST, there are two errors in the schematic diagram shown in Figure 2. The value for R3 in the parts list (5.1 kΩ) is correct, but in the schematic it is incorrectly shown as 1.5 kΩ. Also, the chassis ground and –12 V connections at the ends of R1 and R3 were swapped. The ground connection should be at R3 and the -12 V connection should be at R1.

    In “A Tube-Based Bench Supply for Tube Projects” by Bryant Julstrom, KC0ZNG, that appeared in the August 2014 issue of QST, the label for resistor R11 is shown in the Figure 2 schematic diagram, but not the schematic symbol for the resistor. The symbol should appear next to the label between R12 and the junction of the common pole of switch S3 and the +HV output. Also, vacuum tube V2 is correctly labeled as a 12AU6 in the schematic diagram, but is incorrectly listed as a 12AV6 in the Figure 2 parts list.


    In the article “Antenna Masts: Safety and Selection” by Don Daso, K4ZA, in the September 2014 QST (page 30), there is a statement that DX Engineering offers software to calculate stress on masts. This is inaccurate. The DX Engineering Mast Load Estimator is an on-line calculator that allows the user to model an installation to determine which of the two mast sizes sold by DX Engineering is adequate for the proposed installation. It is specific to only those two masts. There is also DX Engineering mechanical calculation software (YagiMechanical) available, but it does not calculate mass stress.


    In the article "A New Life for an SB-610 Monitor Scope" by Dave Cook, WA0TTN (page 37), we neglected to include an updated author biography with the address to his web site for more information. You can find his web site at

      In the article "Add 40 Meters to a 24-Foot Boom Yagi" by Michael Foerster, W0IH (page 40), the first sentence of the second paragraph states that the omega match used two 200 to 250 uF variable capacitors. The unit of capacitance should have been picofarads (pF).

    A few errors crept into the “Hands On Radio” column by Ward Silver, N0AX, in the October 2014 QST. In Figure 3, the + and - inputs to the input amplifier are reversed. "Input" should connect to pin 2 (the non-inverting input) and "VREF" through R1 to pin 3 (the inverting input).  This will result in the output of U1A being zero when Input and VREF are equal. VREF and Input must both be ground-referenced. In addition, pin 4 of U1 should be connected to V- (a negative voltage) and not ground as shown. The supply should be at least ± 6 V as indicated in the text.

      In “Extended Double Zepp Yagi Antenna” by William Alsup, N6MXW, that appeared in the October 2014 QST, page 34, the dimensions shown in Figure 1 are for operation on 20 meters. This is not mentioned in the figure caption or the article.

    Ralph Crumrine, N0KC, author of “A 1500 W Centennial Amplifier for the 80 – 6 Meter Bands,” published in the December 2014 issue of QST (page 30), advises that two versions exist of the Ohmite Model 111 tap switch used for the band selector switch, S301A. Old stock might be ceramic; new stock will be plastic. The ceramic bodied part must be used.  The Model 212 switch is ceramic only and might be a useful substitute.


    In "Transceiver Power Control Accessory" by Phil Salas, AD5X, in the second paragraph on page 38 the author states: "With S1 set to NORM, the voltage at ALC XCVR and ALC AMP should vary . . ".


    The sentence should have read: "With S1 set to NORM, the voltage at ALC XCVR should vary . . ."


    You can't measure voltage at ALC AMP because that is after a reverse-biased diode.


  • 2013


    Issue Feedback

    In “Hands-On Radio” [Jan 2013, pp 63-64] the output connection in Figure 3 (B) should be to the normally open (N.O.) relay contact.

      Check the "QST-in-Depth" web page for corrections to Cheap and Easy SDR [Jan 2013, pp 30-35]

    In “Down Periscope” [Jan 2013, pp 36-38] The galvanized steel pipe identified in the “Mounting Arrangement” section should be 1 1/4 inch, not 1 1/2 inch diameter.


    In “A Sampling Down Converter for Low Frequency Oscilloscopes” [Jan 2013, pp 39-45] the description of L1 in Figure 2 is incorrect. Please use the description in the parts list instead. In Figure 3, the INPUT and OUTPUT terminals of U7 are shown reversed.



    In “A Three to One Dummy Load” [Feb 2013, pp 30-32] there is an inconsistency between the wiring of R6-R9 in Figure 1 and the text. The text describes them interconnected at the intermediate point (bottom of R6 to bottom of R8), while the schematic doesn’t show the connection. Either arrangement will provide the desired 1:1 SWR.

    In “The Penticton Solar Flux Receiver” [Feb 2013, pp 39-47] the lead map incorrectly shows Lake Sakakawea in Montana. It should have been shown in North Dakota.


    In Figure 3 the block labeled “2.75-2.85 GHz Band-pass Filter” in both the A1 and B1 paths should read “GasFET Amplifier.”


    In “Digital Detective” [Feb 2013, p 80] in the digital edition of QST, the link text is correct but the link address is not. When selecting the link, change “8661” to “8861” and you will be able to access the correct web page.


    In Figure 1 of “An MCW Keyer for V/UHF FM” [Apr 2013, pp 37-38], Q1, Q2, Q4 and Q5 are misidentified as PNP transistors. They are actually NPN types. The base diagram for the Q3 is correct as shown, just its label has a typo.


    In “Overvoltage Protection for ac Generators” [Apr 2013, pp 43-46], some of the identified parts are no longer available, or are not available in single unit quantities. Please make the following changes:


    C1 — 220 µF, 35 V electrolytic capacitor (Digikey P5166-ND).

    DS1, DS7 — Red LED (Digikey 751-1129-ND).

    DS3-DS5 — Green LED (Digikey 751-1099-ND).

    DS2, DS6 — Yellow LED (Digikey 751-1144-ND).

    The original amber LED is no longer available in 3 mm size so that has been changed to yellow.

    ●In “Overvoltage Protection for ac Generators” [Apr 2013, pp 43-46], the author provided the following update: If you are using the circuit board from Far Circuits, note that they have included the two jumpers I discussed as connection on the board. Thus, you will not be able to use the on-board jumpers as part of the calibration process. Instead, you will have to carefully touch your positive voltmeter probe to the LM-3914-1 pins. The negative lead attaches to the negative foil strip on the bottom of the board where the negative lead of capacitor C1 is attached.

    LM-3914-1 pin 6 is for the lower voltage setting (0.35 V dc) and pin 4 is for the higher voltage setting (0.55 V dc). Remember, those are starting voltages and will have to be adjusted a little.

    Remember, while making adjustments, avoid contact the leads going to the GFCI and with R5 and U3, including the foil side of the board around those components.

    • In "Remote Control of Accessories via the Internet" [April 2013, p 31] in the Figure 1 parts list, the K1-K8 SPDT relays should be identified as Digikey part 225-2077-ND or Mouser part 769-JQ1P-12V-F. These are only examples of relays that can be used in this project.  Relays should be selected based on the ac or dc voltages and currents required by the devices being switched
    • In “Build a Linear 2 Meter 80 W All Mode Amplifier,” by James Klitzing, W6PL [May 2013, p 30-34], two heat sinks are included in the parts list, but only one is necessary, specifically: Heat sink extrusion 5.375 x 8 x 1.375 inches (Heat Sink USA A008).

    • In “Up Front” [June 2013, page 20], the photo at the upper left corner of the page with the caption "On the road with the tower trailer" is actually a photo of different tower trailer that the author built in the 1970s and towed from California to Vermont. It is not the same trailer shown in the rest of the article.


    • In “Forty-Three Million Miles per Watt” [June 2013, page 63], it is stated that the roundtrip distance to the Moon is 756,000. This is an error. The true distance is about 477,714 miles.
      In “The Doctor is In” [Jul 2013, pp 54-55], there is a typo in the response to William, W5VDM. The correct formula for the approximate distance to the radio horizon is 1.32 × [height (ft)]0.5.

    In “The Real Q-Pole” [July 2013, pp 37-38] the spacing between the rods of the Q section is 2 3/4 inches measured at the outer edges of the two elbows, not 1 1/2 inches as shown in the diagram.  This is not an electrically critical dimension, but should be noted.


    • “Hands-On Radio” column #127 [August 2013, pp 53-54] mistakenly uses 1.866 for the square root of 3 when the correct value is 1.732. The correct voltage between two phases of a three-phase 120-V system is then 120 x 1.732 = 208 V.  Two hundred and forty volts would be supplied in a split-phase system with each phase supplying 120 V.


    • In “The August 2013 Rookie Roundup – RTTY” announcement [August 2013, p 82] the photo caption is inaccurate. The operator on the right is Eugene Mah, KK4JRP (now AB4UG). The photo was taken by Thomas Glaab, AJ4UQ, and the club is the Charleston Amateur Radio Society (CARS, not CARC).
      In the article “A Cascaded Current Transformer RF Coupler” by Ralph Crumrine, N0KC, which appeared in the November 2013 QST, page 52, the Steward core number shown for transformer T2 is incorrect. The correct part number is 28-0375-400.
      In the article, " How Much 'Punch' can You get from Different Modes?" by K. Siwiak, KE4PT and B. Pontius, N0ADL, that appeared in the December 2013 QST, page 30, there is an error in the PSK31 entry of Table 2, which propagates to Figures 3 and 4. In Table 2 last column, PSK31 should be +4.8 dB. In Figure 3 PSK31 should be 7 dB, and in Figure 4 the range for PSK31 should be 2X.

  • 2012


    Issue Feedback  
    January The article “A Transistor Tester in a Tin” [pp 30-31] has three problems. In Figure 1, the sketch of the TO-92 transistor (the lower unit) has its emitter (E) and collector (C) leads reversed. BT1-3 should be AAA size batteries to fit in the Altoids can. The headphone connection, J1, is correct as shown for headphones with dc continuity, such as dynamic headsets. If a crystal earphone is used, the bottom of R7 should be grounded and the earphone connected between the top of R7, in parallel with the emitter, and ground. Note that with this change there will be current drawn from the battery at all times, so at least one battery should be removed when the unit is not being used, or a power switch should be added.  
     February In “Product Review — Four 25 A Switch Mode Power Supplies” [pp 56-59] some updates were not made following Ten-Tec’s replacement of the 941 supply with a current unit. On page 59, under “Lab Testing” in the first column, it should now say: “The supplies here all tested between 110 mV and 490 mV, most in line with the best of supplies reviewed previously.” In the third column it should now say: All of power supplies tested here passed part 15 requirements for conducted emissions. Overall the QJE DX PS30SWII and Ten-Tec 941 were the quietest of the units tested, followed closely by the Jetstream JTPS30M.  
      We have learned that the image we have been describing as AMSAT-OSCAR 51 [see, for example, p 87] is actually a different satellite. ― tnx Drew Glasbrenner, KO4MA  
    March In “Webcam Microscope for the Radio Amateur” [pp 38-39] the name of the author of the referenced article is Jim Koehler, VE5FP, not Joe.  
       In “A Coaxial Vertical for 160 and 80 meter” [pp 30-32] the entry for Section 4 in the caption for Figure 5 should be 3960 not 1960 kHz.  
      In “Hands-On Radio” [pp 59-60] Ed, N5KZW, points out that to bring your workplace up to standard practices for ESD, the best method is to use a static dissipative mat and cuff. These are widely available from distributors such as Digi-Key and Jameco. With their current-limiting series resistance, these are also safer in case of electrical fault.  
    April In "The Doctor is In" the correct call sign of Elwood who contributed the link about meteor pings is WB0OEW.  
      The antenna photo on page 120 of the Apr 2012 issue was taken by Tim Raven, G4ARI.  
      The cover of the Apr 2012 issue should have referred to RMS Titanic, not HMS.  

     In “Level Converter to Allow Full Control of Peripherals by Computer or Radio” [pp 38-40] the ground connection on J4 should go to pin 5, not pin 4. Also the "Hamspeak" item was in error. It should have read:

    Null Modem -- An adapter to interconnect two devices both wired as EIA RS-232-C DCEs or DTEs using DSUB25 or DSUB9 connectors. To allow communication, interconnect RECEIVE DATA (pin 3) on one connector to TRANSMIT DATA (pin 2) on the other for either connector type. The SYSTEM GROUND connection should also be interconnected end to end -- pin 7 on DSUB25, pin 5 on DSUB9.

    For most devices that require flow control, cross connecting CLEAR TO SEND and REQUEST TO SEND either at each connector, or from end to end, will allow data flow. Some implementations may also require DATA SET READY and CARRIER DETECT at one end connected to DATA TERMINAL READY at the other.


    In “The 43 Foot Vertical What’s the Magic,” June 2012, pp 30-31, I was remiss in not mentioning that the 43 foot vertical, as any monopole fed against ground, requires a good radial ground system to be efficient. The radials can be on or under the ground, or can be elevated. If you’re not familiar with the requirements for such a system, please look over the excellent QST article by Rudy Severns, N6LF, on the subject.1 J. R. Hallas, W1ZR, Technical Editor, QST.

     1R. Severns, N6LF, “An Experimental Look at Ground Systems for HF Verticals,” QST, Mar 2010, pp 30-33.

    July  In the 2011 ARRL 10 Meter Contest Results (July 2012, pp 80-83), the DX winner of the Single Operator, Phone Only, High Power category was listed as LP1H (LU5HM, op). This is incorrect. The correct winner was KP2A (KW8N, op).  

    In “A Digital Interface for Fldigi” [Aug 2012, pp 36-38] Figure 1 shows the connectivity of the output pins of U2 in error. Pin 4 should go to MIC GROUND, pin 5 should go to PTT and pin 6 should be left unconnected.

    The miniature audio isolation transformers, T1-T3, are no longer listed by RadioShack. Rick, WA6NUT, suggests the Triad TY-145P as a suitable replacement. It is available from the usual suppliers, including Jameco ( Mouser (


    In “My Tuner Tuned My Antenna — But Now It Doesn’t!” [Aug 2012, p 47] the caption to Figure 1 should say TLW TUNER output, not EZNEC TUNER output

    In “The Uncooperative Tree” [Sep 2012, p 30-32] the value of the inductors in Figure 2 should have been shown as 33 μH.


    In “Power Carts for Scouts and Field Operations” [Sep 2012, pp 36-40] switch S3 in Figure 6, shown as a DPDT center-off switch, could be a SPDT center-off unit instead.


    In “The Evolution of DX Spotting” [Oct 2012, pp 71-72] the author noted that he used the work “splitter” when he meant “skimmer” when describing certain terminology related to the Reverse Beacon Network.

      In "Those Mysterious Signals" [Oct 2012, pp 37-39] the correct URL in note 4 is  

    ● In “Boat Anchor Buddy” [Nov 2012, pp 53-56] there should have been a footnote indicating that PC board files and other layout information is available on the QST in Depth website.


    In “Boat Anchor Buddy” [Nov 2012, pp 53-56] the parts list in the caption of Figure 1 has the values of C5 and C6 reversed, they are shown correctly in the schematic. R11 is missing from the parts list and is a 6800 ohm resistor like R13. In Figure 1, Q7 has the collector and emitter leads reversed. The board layout is correct.


    In “Boat Anchor Buddy” [Nov 2012, pp 53-56] some builders have experienced excess current and heat in the NE555 timer IC. Lower current operation will be achieved by removing R6 from the + 12 V line and inserting it between pin 3 of U1 and the base of Q4. A revised layout drawing is on the QST-in-Depth website at


    ● In “Building Inexpensive HF Power Attenuators” [Nov 2012, pp 32-33] the first formula on page 32 should indicate 1.41 A, not 0.71 A.


    In “Have Fun Building the Simplest Transmitter” [Nov 2012, pp 46-49] the author has provided some additional coil data. He notes that his 40 meter L3 is five turns, wound exactly as L2 and that he uses his 40 meter L2 as his 80 meter L3.  The value of R1 is not shown. The correct value is 100 kohms, 1 W.

    In the “Power Supply Options” sidebar C1 and C2 are 8 μF, 450 V electrolytic capacitors. They are available from Antique Electronics Supply (, part number C-SA8-450.


    The author of “Distracted Driving and Amateur Radio—A Civil (Law) Perspective” [Nov 2012, pp 81-82] has sent us an update regarding his article. The article includes the statement: “In Illinois, an effort by ARRL officials quickly convinced the legislature to adopt a blanket exemption for Amateur Radio from the measures being considered.” The final legislation (Public Act 97-828) that was adopted does not appear to contain the blanket exemption for Amateur Radio. The blanket exemption has been amended onto another bill that remains in committee and is unlikely to be passed this session but could be reintroduced next year.


    In “PSK-31 Operation on 2 Meter FM” [Dec 2012, pp 37-38] in Figure 1, the word “Ring” should be further to the right to line up with the contact for the right channel. The portion of the connector on the far left is the “sleeve.” In addition, the tip should be shown to the right of the ring.

    In “Product Review—Elecraft KX3 HF and 6 Meter QRP Transceiver” [Dec 2012, pp 39-44] the last word of the first paragraph under What’s In The Box on page 39 should be “translator,” not “transistor.”


    In “Life Members Elected” [Dec 2012, p 60] Brad R. Woodward, KG4FUS, was included in the list in error.