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References for Chapter 6.
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[1a] "Wheatstone's
Bridge" (J A Fleming) The Encyclopaedia Britannica,
13th Edition 1926. Volume 27. [1b] "Pioneers of Electrical Communication - Charles Wheatstone IV". Rollo Appleyard, Electrical Communication, Vol. 6, No. 1. July 1927. p2-12. [2] Advanced Level Physics, M Nelkon and P Parker, 3rd edition (SI) 1974, Heinemann, London. ISBN 0 435 68636 4. Ch 33: Wheatstone Bridge p829. [3] Radio Designer's Handbook, Ed. Fritz Langford-Smith. 4th edition. 4th impression (with addenda), Iliffe Publ. 1957 [A later reprint exists (1967) ISBN 0 7506 36351] Arm (Definition), section 4.7. [4] Electrical Measurements and Measuring Instruments, E. W. Golding. 3rd edition, Pitman, London, 1949. Schering bridge, p154-158. De Sauty bridge, p214-216. [5] "Measuring RF Power", Joe Carr [K4IPV], Electronics World, Nov. 1999 p942-948. Dec 1999 p1000-1005. Part 1: Definitions and dB notation, thermistors, bolometers, thermocouples, diode detectors. In-line bridges: Micromatch [Christie with capacitive ratio arms], Monomatch (sic) [two types: Coupled transmission lines. Current transformer with capacitive voltage sampling, current summing configuration]. Part 2: Bird 'Thruline' wattmeter. Calorimeters. Micropower measurement techniques. Mismatch loss and mismatch uncertainty. [6] The ARRL Antenna Book, 19th edition, ARRL publ, 2000. ISBN: 0-87259-804-7. Coaxial cable data p24-19. Ch 27: Transmission-Line and Antenna Measurements Bridge types p27.4. SWR Measurement p27.2-27.21. Tandem Match accurate directional wattmeter [Sontheimer-Fredrick with Faraday screen and diode-linearity compensation] p27.9-27.19. "A Noise Bridge for 1.8 through 30 MHz" p27.24-27.31 [TRAB using tone-modulated zener-diode noise source and radio receiver as detector. Transformer is wound on Amidon pig-nose (2-hole) core type BLN 43-2402, 3 turns primary, 3+3 turns secondary]. [7] "Modern Impedance Measurement Techniques", Alan Bate, Electronics World, Dec. 2002, p12-18. Jan 2003, p18-25. Feb 2003, p49-56. Mar 2003, p52-59. Review of professional impedance measurement techniques: Basic bridges. Three-terminal measurements. Bulk metal film reference resistors. Guard amplifiers. Phase sensitive detectors. [8] The Inventor of Stereo: The Life and Works of Alan Dower Blumlein, Robert Charles Alexander, Focal Press 1999. ISBN 0 240 51577 3. Book has related website: http://www.doramusic.com/index_blumlein.htm The closely coupled inductor ratio-arm bridge' is discussed on page 21. See also: British pat. no. 323037. [9] Radio Frequency Transistors, Norm Dye and Helge Granberg. Motorola inc. / Butterworth Heinemann, Newton MA. 1993. ISBN 0-7506-9059-3 Line-length resonance: p142. [10] "The Simple Diode RF Detector", Michael E Gruchalla, Communications Quarterly, Fall (Oct) 1999 p7-14. Why a DC return path is needed. The shunt-diode configuration. [11] "RF chokes, their performance above and below resonance" Courtney Hall WA5SNZ, Ham Radio, June 1978 p40-42. Due to self-capacitance, an RF choke behaves as a parallel resonant circuit. [12] The Art of Electronics, Paul Horowitz [W1HFA] and Winfield Hill, 2nd edition 1989, Cambridge University Press. ISBN 0-521-37095-7. Tunnel (Esaki) diode p14-15, & p1060. Back diode p891, 893. Ebers-Moll equation, p79-80. Detectors (non-linearity compensation), p888-892. [13] Physics of Semiconductor Devices, S. M. Sze, Wiley & Sons, New York, 1969. SBN 471 84290 7. Section 8.2: Schottky Effect. [14] "Errors in SWR Meters", Albert E Weller, WD8KBW, QEX Correspondence, June 1982, p2. Errors due to diode non-linearity. [15] "Diode Voltmeters", Albert E Weller Jr., WD8KBW, QEX, April 1983, p3, cont p6. Non-linearity compensation scheme. [16] "The Theory of Diode Voltmeters and Some Applications", Albert E Weller, WD8KBW, QEX Jan 1984, p7-14. [17] "Calibrating Diode Detectors", John Grebenkemper, KI6WX, QEX, Aug 1990, p3-8. [18] Agilent Technologies [HP]. www.agilent.com/ Agilent 1N5711, 1N5712, 5082-2300 Series, 5082-2800 Series, 5082-2900 Schottky Barrier Diodes for General Purpose Applications. Data Sheet. AN923: Schottky Barrier Diode Video Detectors. AN956-4: Schottky Diode Voltage Doubler. AN956-5: Dynamic Range Extension of Schottky Detectors. AN956-6: Temperature Dependence of Schottky Detector Voltage Sensitivity. AN986: Square Law and Linear Detection. AN987: Is Bias Current Necessary? AN988: All Schottky Diodes are Zero Bias Detectors. AN1156: Diode detector simulation using Agilent Technologies EEsof ADS software. [19a] Philips Components Quick Reference Guide 1990. [19b] Mullard semiconductors 1974/5. [19c] Mullard industrial semiconductors quick reference guide 1969/70. [20] Radio Engineering, Frederick Emmons Terman, McGraw-Hill, 3rd edition 1947. Thermionic diode forward voltage drop, section 5.5. [21] "New approach to measuring SWR at high-frequencies", Ulrich L Rohde DJ2LR, Ham Radio, May 1979 p34-35. Discussion of the circuit of the Rohde & Schwarz NAUS 80 RF power meter, which uses transformers for both current and voltage samples, and overcomes the diode forward-threshold problem by using back-diodes. Attributes the capacitive voltage sample / current transformer bridge to a German inventor, one Dr Buschbeck "more than 30 years ago" [i.e., before 1949], but draws Buschbeck's circuit without secondary loading of the current transformer [possibly an ommission]. [22] "Effective noise reducer and hearing protector" Dr Robert L Rod, K6FZ, Hints & Kinks, QST Apr 1978, p40. Simple audio clipper circuit using back diodes. Article gives V/I curve for Gen. Electric BD1. The BD1 had a forward voltage drop of 90mV @ 10mA, but appears from the graph to have about 1mA leakage for a reverse voltage of 500mV. [23] Amplifier Handbook, Ed. Richard F Shea. McGraw Hill, 1965. Ch 12: Tunnel Diodes and Backward Diodes. Chang S Kim and Jerome J Tiemann. [24] The ARRL Handbook 2000, 77th edition. ARRL publ. 1999, ISBN: 0-87259-183-2. Ch 22: Station Setup and Accessory Projects: Tandem Match accurate directional wattmeter [Sontheimer-Fredrick with Faraday screen and diode-linearity compensation], p34-40. Ch 26: Test Procedures and Projects: 1.8-30MHz Noise Bridge p36-38. Return Loss Bridges p41-42. [25] "The Tandem Match - An Accurate Directional Wattmeter" John Grebenkemper KA3BLO, QST Jan 1987 p18-26. [26] "A Sensitive Antenna Bridge", Ian Braithwaite, G4COL, Rad Com, July 1997, p38-39. Christie/Wheatstone bridge using NE592 Wideband differential RF amplifier to amplify the detector signal prior to rectification by a voltage doubler using two OA47 diodes. The use of a differential amplifier eliminates detector ground referencing problems, and the NE592 is good to at least 65MHz. [27] "VHF millivoltmeter", Nick Wheeler, Electronics World, July 1998, p604-605. Surface-mount design using CF739 GaAsFET input stage and Schottky rectifier. Useful up to 150MHz. 50mV RMS FSD. [28] "A Sensitive RF Voltmeter", John Pivnichny N2DCH, Ham Radio July 1989, p62-64, 67. 0.5 - >30MHz voltmeter based on the MC1350p or MC1590 RF amplfier (uses two ICs), with simple shunt-diode rectifier. 100μV-100mV FSD ranges. [29] "An RF Voltmeter", Ian Braithwaite, G4COL, Ham Radio, Nov 1987, p65, 67, 68, 71, 73, 75. Linear voltmeter. 10KHz - 150MHz, <70mV - >3VRMS. Uses direct rectification (Schottky shunt-diode) and diode compensation scheme - rectified signal is compared to a locally generated sine-wave rectified by an identical diode, the magnitue of the reference signal being controlled by a servo loop. [30] "Tone Modulated HF Impedance Bridge", E Chicken MBE, G3BIK. Rad Com, June 1994 p13-16, July 1994 p69-70. TRAB using tone-modulated zener-diode noise source and radio receiver as detector. Frequency range 1-30MHz. Transformer is wound on Amidon FT50-43 toroid (0.5", μi≈900), 8 turns primary (≈33μH), 16 turns centre-tapped secondary. [31] "Noise bridge measurements", Brian Horsfall, G3GKG, Rad Com, April 2003, p68-71. TRAB using zener noise source and radio receiver as detector. Transformer is the same as in ref [6] p27.9-19. Couples to receiver using transformer (Amidon FT37-77, 5:5 turns) to float the unknown from earth. Obtains 9:1 scale expansion by coupling reference resistor via a 3:1 auto-transformer (FT37-77 12 turns tapped at 4). [32a] "A Simple and Accurate Admittance Bridge", Wilfred N Caron, Communications Quarterly, Summer (July) 1992, p44-50. Admittance TRAB for 2-30MHz using Amidon BLN 43-202 two-hole core (AL=2.89μH/turn²) with single-turn RG174U Faraday shielded primary and 3-turn twisted bifilar secondary. Calibration procedure using deliberately mis-terminated coax cable. [32b] Forrest Gehrke, K2BT, Communications Quarterly (Correspondence), Winter (Jan) 1993, p92-93. Zenner noise source for the bridge. Advantages and limitations of the transmission-line transformer approach. [32c] "RF Impedance Bridge for 2-30MHz", Jack Gentle, G0RVN, Rad Com July, 1995 p38-42. Article based on ref [32a], above. Transformer ratio-arm admittance bridge. Erratum: Transformer core is given as: "BLN 43-2023"; this should read: 'BLN-43-202'. [32d]"Capacitor Calibration for the RF Z-Bridge", Jack Gentle, G0RVN, Rad Com, Aug1995 p61 & 63. [33] Radio-Frequency Measurements by Bridge and Resonance Methods, L. Hartshorn (Principal Scientific Officer, British National Physical Laboratory), Chapman & Hall, 1940 (Vol. X of "Monographs on Electrical Engineering", ed. H P Young). 3rd imp. 1942. Ch. I, section 3: Defines Admittance as Y=G+jB, hence BL=-1/ωL and BC=ωC. [34] Physical Electronics, C L Hemenway, R W Henry, M Caulton, Wiley & Sons, New York, 2nd edn. 1967. Library of Congress cat. card no. 67-23327. Section 14.6: The tunnel diode, p290-294. [35] "Simple Quiet Tuning and Matching of Antennas" M. J. Underhill G3LHZ, Rad Com, May 1981, p420-422. The directional couplers in a reflectometer are linear reciprocal devices. The antenna can be matched in receive mode by injecting a small signal into a reverse wave directional coupler in the line to the ATU. The antenna is matched when the level of injected signal heard in the receiver is minimised. The injected signal can be from a noise source, or it can be a comb-spectrum from, say, a crystal calibrator. The injected signal is too weak to interfere with other stations, being undetectable at about 1 wavelength from the antenna. [36] "A Quiet Antenna Tuner", Tony Lymer GM0DHD, QEX May/June 2002, p9-12. Underhill-Lewis method. QRP single-core version of Sontheimer-Fredrick, performs well from 1.8 - 146MHz. [37] "RF Auto-transformers - Transmission Line Devices modelled using SPICE", Nic Hamilton, G4TXG, Electronics World, Nov. 2002, p52-56. Dec. 2002 p20-26. Part 1: Limitations of the conventional transformer model. Transmission line model. Part 2: Core losses. Winding resistance. [38] Amidon Associates Inc. (Technical data book) Jan 2000. Technical data for iron powder and ferrite cores, including AL values, frequency ranges, wire packing tables, Q curves, etc. Maximum flux density calculations and recommendations: p1-35.  Information is
also available online from: www.amidoncorp.com . |
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[40] "An
Inside Picture of Directional Wattmeters", Warren B
Bruene W0TTK [now W5OLY], QST April 1959 p24-28. [41] "In-Line RF Power Metering" Doug DeMaw W1CER [now W1FB], QST Dec 1969 p11- 16. Construction article for Bruene-type bridges for 3.5-30MHz. [42] Ferromagnetic Core Design & Application Handbook, M F "Doug" DeMaw W1FB, 1st edition, 2nd printing 1996. MFJ publishing co. http://www.mfjenterprises.com/ . Bruene bridge: p94-95. [43] "Automatic Tuning of Antennae". M J Underhill [G3LHZ] and P A Lewis. SERT Journal, Vol 8, Sept 1974, p183-184. Reprint of paper in Mullard Research Labs Annual Review, 1973. Introduces the idea of using phase, resistance, and conductance for unambiguous adjustment of the matching network in automatic antenna tuning systems. Describes the matching process using Z-plane diagrams, and operations involving lines of constant resistance and circles of constant conductance. Advocates the use of a π-network with one or other of the capacitors set as near as possible to zero capacitance (i.e., using the π-network as an L-network, but without the need for switching), on the basis of minimised voltages and low-pass filtering. Notes that the input impedance of a 'typical' antenna operating between 1.5 and 30MHz can have a resistive component between 3 and 2000Ω, and a reactive component between -2500 and +500Ω. Gives criteria for achieving 1.2:1 SWR, i.e., 45 ≤ R ≤ 56Ω, 17.5 ≤ G ≤ 22.5 mS, -7° ≤ φ ≤ +7°. [44] After the Second World War, the 160m band remained unavailable to USA radio amateurs until 1955 (see AC6V's Amateur Radio History page). Even then, the band was primarily allocated to the Loran navigation system. Hence many amateur and commercial circuit designers simply ignored the existence of the 160m band, and to many operators, HF started at 3.5MHz. The problem with a current transformer bridge designed to work from 3.5MHz up, is that it still seems to work when you try it on 160m, and the user has no way of knowing that it is grossly innacurate. This is one source of the folklore relating to the difficulty in getting a radio station to work on 160m. The other is the myth that you need an 80m long back garden. [45] "VSWR Bridges", Will Herzog K2LB, Ham Radio, March 1986, p37-40. Brief review of the pitfalls of SWR bridge design, particularly the problem of phase error. Companion article to US Pat. # 4739515. [46] BICC Cableselector E15. PTFE Coaxial Cables. July 1979. [47] MFJ-269 SWR Analyser. Despite the alarming lack of quantitative information in the manual on the subject of instrumental accuracy; the author's MFJ-269 gives good inductance measurements. Readings in the region of 10μH at the lowest working frequency (1.7MHz) agree within 2% with measurements made using a Hatfield LE-300/A1 at 1.5915MHz (error ±0.5%). The facility for capacitance measurement appears somewhat crude by comparison: readout is to the nearest pF and error is about 10% in the region of 100pF; but this limitation can be worked around with the aid of a calculator. The trick is to use the displayed reactances and subtract an offset for the jig capacitance, all of which can be done using readings from the instrument itself. It is possible in this way to measure small capacitances to about 1 decimal place in pF, making the MFJ-269 useful in the lab. as well as when fettling antennas. [48] Soft Ferrites: Properties and Applications. E C Snelling. 2nd ed. Butterworth. 1988. ISBN 0-408-02760-6. Permittivity of ferrites: p127 - 129. [49] "Parasitic Capacitance Cancellation in Filter Inductors". T C Neugebauer and D J Perreault. 35th Annual IEEE Power Electronics Specialists Congerence, 2004. The parasitic capacitance of a power-supply filter inductor can be cancelled by use of an auxiliary winding and a capacitor. [50] "Hickman's Analog and RF circuits", Ian Hickman. Newnes 1998. ISBN 0 7506 3742 0. p183. |
© D W Knight 2007.
David Knight asserts the right to be recognised as the author of this document.
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