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UNCLASSIFIED
AD 414889
DEFENSE DOCUMENTATION CENTERFOR
SCIENTIFIC AND TECHNICAL INFORMATION
CAMERON STATION, ALEXANDRIA. VIRGINIA
UNCLASSIFIED
NOTICE: When goverent or other drawings, speci-fications or other data are used for any purposeother than in connection with a definitely relatedgoverment procurement operation, the U. 8.Government thereby incurs no responsibility, nor anyobligation vhatsoever; and the fact that the Govern-ment may have formlated, fUrnished, or in any waysupplied the said drawings, specifications, or otherdata 1o not to be regarded by Implication or other-wise as in any anner licensing the holder or anyother person or corporation, or conveying ay ribtsor permission to manufaoture, use or sell anypatented invention that ay In any way be relatedthereto.
6• Development of
RF ATTENUATORS
-Technical Report
toU.S. Naval Weapons Laboratory
Dahlgren, Virginia
Contract N178- 8056Nov. 1, 1962 to June 30,1963
(Completion of Phase 1)
Scintilla DivisionSIDNEY. NEW YORK
Ei:
(
Technical Report
November 1, 1962 through June 30, 1963
on
Radio Interference Guard (RIG)
Low-Pass Radio Frequency Attenuator
for the
U. S. Naval Weapons Laboratory
£ Dahlgren, Virginia
Contract No. N178-8056(Completion of Phase II)
Prepared By /Karl KrausChief Engineer, RF Connectors and Allied Products
Approved By 0 4 ~rr# e:,~-
rge Swansonngineering Manager - Electrical Connectors
( The Bendix CorporationSCINTILLA DIVISION
Sidney, New York
Preface
The U.S. Navy's Hazards of Electromagnetic Radiation toOrdnance (HERO) Program is concerned with providing adequateprotection of weapon electro-explosive devices (EEDIS) againstspurious energies induced in their associated circuits by electro-magnetic fields. The source of this spurious energy is generallyshipboard radar and communications equipment. The use of thisequipment must now be restricted during certain operations withordnance, or the ordnance operations must be accomplished ata point remote from the transmitting antennas.
As a result of studies made under the HERO Program, aminiature low-pass attenuator of novel design and capabilitieshas been conceived. This device employs the intrinsic low-pass characteristics of a metal barrier in a filter and/or attenuatorapplication as a means of protecting EEDIS from spurious radiofrequency energies.
Feasibility of this device, known as the Radio Interference Guard(RIG) RF Attenuator, has been demonstrated and a patent applicationwas filed at the U.S. Patent Office on 29 December 1961 underNavy Case No. 33460 Patent Serial No. 163162 by Wing CommanderR. I. Gray.
4-1-
Table of Contents
Paragraph Subject Page
1.0 Summary I2.0 General Requirements 13.0 Theory 23.1 Theory of Operation - Single
Unit RIG 23.2 Theory of Operation - Double
Unit RIG 34.0 Detailed Report 44.1 General Description 44.2 Manufacturing Comments4.3 Analysis of DC Attenuation
Two Unit Design 54.4 Testing 124.5 Test Procedures 134.6 RF Test Results 134.7 DC Attenuation Results 144.8 DC Heat Rise 144.9 AC Heat Rise 144. 10 10 and 100 Megacycle Attenuation 144.11 Firing Current Response Time 154.12 Environmental Testing 154.13 Retest of RIG 118 165.0 Conclusions 166.0 Recommendations 17
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List of Illustrations
Figure Subject Page
1 Circuitry for Single Unit 22 Circuitry for Double Unit 33 Test Circuit for Double Unit 34 Network for Double Unit 55 Network for Double Unit 66 Single Unit Circuit 87 Coaxial Cable Cross-section Diagram 118 Attenuation Vs. Frequency for Various
RIG Groups 18
9 Attenuation Vs. Frequency for VariousMaterials -. 0015 in. Wall 19
10 Attenuation Vs. Frequency for VariousMaterials -. 003 in. Wall 20
11 Attenuation Vs. Frequency for VariousWall Thicknesses - 99% Iron 21
12 Attenuation Vs. Frequency for VariousWall Thicknesses - #42 Alloy 22
13 RIG Design Curves 2314 RIG Design Curves 2415 RIG L-19910-49 25'16 RIG L-19910- 6 6 2617 RIG L-19910-70 2718 Photograph of RIG's 28
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Tecinical Report
Plase 11
Contract No. Ni78-8065
1.0 Summary
1. 1 This report covers the work accomplished by the Scintilla Divisionof The Bendix Corporation during the period of November 1, 1962to June 30, 1963 of Contract N 178-8056 for the Naval WeaponsLaboratory, Dahlgren, Virginia. Contract N 178-8056 is concernedwith the development of a miniature low pass radio interferenceattenuator device herein referred to as RIG (Radio InterferenceGuard). The objective is to develop and determine the mostsuitable design, materials, and construction techniques to obtainoptimum efficiency and reliability of the RIG device as well asto fabricate prototype models and conduct necessary RF attenu-ation and environmental tests in accordance with Scintilla DivisionProposal 619, Development of RF Attenuators for Project HERO,and contract N 178-8056.
1.Z The work accomplished under the contract during the period fromJune 1 to October 31, 1962, as described in the previously issuedPhase I report, was concerned with the basic theory of operation ofthe RIG and with the development and testing of six RIG designs.Further work with these designs is reported herein.
1.3 Based on the results obtained during Phase I, a special designfor a two unit RIG device was agreed upon by NWL and ScintillaDivision personnel in November 1962. The work of developingand determining the most suitable two unit design, materials,and construction techniques for optimum efficiency and reliabilitywas added to the Phase II task and is also reported herein. Thiswork is based on the information, including analytical approachesand preliminary test data, which was previously gained in workingwith the single unit RIG device.
2. 0 General Requirements
2. 1 The following general requirements were established as designobjectives:
2. 1. 1 Squib to be used: The Mark I squib will be used to terminate theRIG device at the present time.
2. 1.2 RIG Requirements:
a. Attenuation
1. DC attenuation is to be 6 db.
2. Attenuation is to be 40 db at 100 KC.
b. Output Current
Output current to be 1. 5 amps minimum.
-I-
C. Firing Volt %ge
28 volts DC, 28 volts 60 cycle, or 28 volts 400 cycle.
d. Response Time
To be a maximum of 10 millisecondls from application offiring pulse to initiation.
e. Breakdown Voltage
To be 100 volts peak on coaxial tube and 1, 000 volts peakfor other components.
f. Power Dissipation
The device at an ambient temperature of 50 0 C shall dissipate10 watts of power at DC and 10 MC for a period of one hour.
g. General Environment
Must withstand requirements of MIL-D-Z1625 and MIL-E-5272C,and must withstand 100 watts for 10 milliseconds in the passband.
3.0 Theory
3. 1 Theory of Operation - Single Unit RIG
3. 1. 1 The theory of operation of the one unit RIG device is describedin detail in the Phase I Revort on this contract.
The circuitry for the single unit is shnwn in figure 1.
5 ohms
EED.75 ohms
28 volts
Figure I
-Z -
3. 2 Theory of Operation - D~ouble Unit RIG
3. 2. 1 The two unit RIG device is to be used asi an RF attenuator in abalanced two wire cirruil. Its purpose and idealized conceptis the same as the single uinit de-vire which in described in thePhase I report. Briefly stated, its puirpose is to reduce to anegligible level the radio frequency power transmitted in theattenuation band without a pprecialy attenuating DC and] lowifrequency AC in the pass hand as explained by Wing CommanderR. 1. Gray i "A Note on the Il~e of Ati en U;, to r sin Ba Iaiw ed andl
Unbalanced Networks" (see appendix).
a. The circuitry for the douible unit is shown in figure 2.
5 ohmsEED
75 ohms
28Bvolt
Figure 2
b. The double unit RIG was tesited ns a single unit device (seefigure 3) becauise there are nio two pini above ground RFgenerators.
Pin A or Inner Conductor PnIo
Outer conductor p-wOuter conductor 79, obt1i18
Figure 3
NOTE: When connected to input Pin A, usne output Pin I,when connected to input Pin B, use output Pin 2.
-3-
4.0 Detailed Report
4. 1 General Description
Five coaxial cable types were wound into RIG devices as shownin design drawing L-19910-49 (figure 15), a sixth and seventhtype were wound according to design drawing L-19910-66,(figure 16), and an eighth type was wound according to designdrawing L-19910-70 (figure 17). The physical dimensions,material, design objectives, and typical electrical values aregiven in Table I (see appendix). It should be noted that drawingsL-19910-49 and -66 show single unit RIG's while drawing L-19910-70shows a double unit design having two windings which are concentricwith each other. The input connector of the latter design is a glassseal Bendix PCIH two pin connector. The output connector is aCannon Twinax TM-RB-M-O.
4.2 Manufacturing Comments
4.2. 1 Insulation of Coaxial Cable
All of che RIG devices were wound using coaxial cable whichwas coated with Dupont ML high temperature polyimide lacquerin the Materials Laboratory. Samples of the cable were bakedfor two hours holding a core temperature of 480 0 F. The insulationof the five samples tested withstood a minimum of 1500 volts DC.
4. 2. Z Winding and Soldering the Coaxial Cable
4.2.2. 1 The wall thickness of the . 0015 in. tubing gave considerable troublein forming around the spool. Due to the thin wall thickness, slightcracks appeared after winding. If any cracks were detected, asevidenced by increase in electrical resistance as well as by a visualdetection, these assemblies were rejected. In the case of the 99%iron, it was necessary to reject all of the first lot of .0015 inchwall thickness purchased and ,order the cable from Uniform TubeCo.
4.2. 2.2. When the two ends of the cente, conductor of the coaxial cablewere soldered to the outside shield, a certain amount of carehad to be used to prevent the outside shield from breaking, yetobtain a good tight solder joint. To generalize, it was necessaryto use care in handling the coaxial cable, and especially the . 0015inch wall type, in all operations.
4.2.3 Resistance Checks
The resistance of the coaxial cable was checked after each sign-ificant operation to ensure proper assembly.
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4.3 Analysis of DC Attenuation - Two Unit Design
4.3. 1 The DC attenuation is dependent on the resistance R1 of theouter conductor and the resistance R4 of the inner conductor.If K and C are the resistances per unit length (ohms/ft) of theouter and inner conductor, respectively, and n is the length (ft)of the cable, then R l and R Z are defined as specified in figure 4.
R2 =Cn
/ \ ______-.7s2R Kn 13 1212T R1 K
R9=5S K Rs:.75 nR ..K
E -28V. 14
R2 :Cn
Figure 4
4.3.2 Using loop analysis, the following expressions may be derived forthe loop currents:
Eg = Rgl 911+ R I (II-I3) + R I (11 - Y
(a) R1 (I1 - 13) R Z 13 + R 1 (13 - 1z)
R1 I1 -I4) = RZ 14 + R 1 (14 - I?)
R e IZ R 1 (13 - 12) +R 1 ( 4 - I)
4.3.3 Since the middle two expressions are identical, it may be concludedthat 13 = 14. This permits the expressions to be written as follows:
Eg = Rg I1 +2R 1 (II - 13)
(b) R (I1 -13) = RZ 13 +R l (13 - IZ)
R I = ZR1 (13 - 1 )
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4. 3.4 The above expressions also happen to be the analysis of thenetwork in figure r.
R R_5-' ' 2 RI- Cn. 13 R<= n
R = 8V Kn.75n
KnE =28V RF=RK
Figure 5
* Therefore it may be concluded that the two circuits (figures 4 and 5)are identical for analytical purposes.
4. 3.5 The expressions for these circuits may be written in the followingmatrix form:
I I R " +R,) (0) -(ZRl] -1 Eg
(c) 12 (0) (Rs Q2R 1 ) (-ZRI) X 01 (-R(-I (ZR 1 +R L0
4. J. 6 This shows that all expressions for current are independent ofeach other and each contains the variables n, K and C. Thesolution of equation (c) gives the following expressions for I land 12:
(RI+ Re + RZR s R2) Eg
(d 1 ) IRI
R R + RzRgR.g s 2R R Rg+ RZRs RIRg RzRg 2RIR 2
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R E
(e.) I . ....... R.RgRs
R R a + .... 4 R1R 4 IHR I1itRg+R R +2R1R 2gN Z R 1 i ~ I g 1
4.3. 7 Expressions (d) and (e) may be written in terms of K, C and n bysubstituting the following relationships into them:
(f) R, Kn
2
(g) R2 -Cn
4.3.8 After these substitutions have been made, equations (d) and (e)can be rearranged to give the following expressions:
I 2[] -(ZS[ c] + 2'- -%(ZS [nC] + 2T)-8 [nG] (2 [nC] + R) T
(h) [( [(E (Z [,,C + R)
K -(2R' [aiC] + 2T') +V(-1 [n ZT')-Hn] 7.(n+ R')T'
Lj 2 [1 C ] (Z [IC] + R')
4.3.9 Where in the interests of brevity:E(j) R--"R s +R - Ig
g 12
(k) S= R +R sg
(1) T =RR8sgs E
(m) R' R + Rg -Il
E(n) T' (R -- R= g
Il
4. 3. 10 Expresajons (h) and (i) make it possible to plot the grouped para-meters -S- and[nCgon a single set of coordinate axes by assigningspecific values to Re (. 75 OHMS), Eg( 2 8 VOLTS) and Rg(5 OHMS).
-7-
The result is two farnilies of curves. The first family comesfrom expression (h)by assigning specific values of 12. The secondcomes from expression (i) by assigning specific values of I Theintersections of these two families gives specific solutions 10rthe circuit.
4. 3. 11 The two families were plotted for a broad range of values of Iand 12 by using data obtained from computer runs. The computerhas been programmed so that additional runs may be made whennew values for R , Rg and E are specified. The plot for the RotR and E previously speciffbd is shown in figure 13. It shouldbe noted tAiat DC power attenuation can be calculated by takingthe I1 and 1z at the intersection of specific curves and substitutingthem into the following expressions:
POWER R input I11(o) ATTENUATION 10 to .
(db) RsZ /
Where:
ZR 1 (4R 2 R 1 + 2R 2 R s + ZR 1 Rs)(p) (4R 2 R 1 + ZR2 R s + 4RIR + 4R l
as derived from the circuit. Combining these two expressions results in.
POWFR (4[( ' ( I + 211, 2 R 4 ZRIR s(q) ATTENUATION -- 0 J
(db) k Z4R RRtI +2R2R + 4RIR.. 4R42 .
4. 3. 12 Of course, expressions (di) and (e) may be substituted into expression(q) giving:
POWER FZRI+RZ) (ZRI4R) -ZR1 2) (R 2 R1+2RsZR 2 R2RR 2 fs 1
(r) ATTENUATION = 10 log(db) 2R I RJ
These results may be compared to those of the single unit circuit shownin figure b.
R R 6g
Eg
Figure 6
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4.3. 13 The expression for the I)C power attenuation in the circuit offigure 6 wam previouHly de rived in thlie l, ha H P I report and is:
POW ER( )((0I ' ¢ ' f i ll; ) 1-'12 )(R'1 4', 4Rl 2 R,, +R' R ' R,(s) ATTENUATION - 10 In I 4(dh)[__i, {
4.3. 14 Comparing expressions (r) and (s) reveals that if R1 = R , R1 = R2andR = 2 R1, the power attenuation of the circuits in figure 4and figure 6 are identical. This agrees with R.I. Gray's con-clusions in his note (see appendix) on the use of attenuators inbalanced and unbalanced networks.
4.3. 15 In effect, the curves in figure 3 are identical to those for thesingle unit except that the abscissa (the nC scale) is multipliedby a factor of I/Z. That this should be so is apparent whenfigure 5, which is the circuit for the double unit, is comparedwith figure 6 which is the circuit for the single unit. These curves
4. give all possible solutions to a7Tnetwork with a 0. 75 ohm load connectedin parallel with it being supplied with a voltage source of Z8 voltsand an internal resistance of 5 ohms. Intermediate intersectionpoints can always be interpolated.
4.3. 16 There are definite relationships between circuit parameters thatwill give the minimum power attenuation. This minimum existswhen the combined resistance of the 7- network connected in parallelwith the load resistance is equal to the load resistance. Underthese conditions the input current has the following value I 1 =(E) /(R s + R ) = (28)/(.75+5.00) = 4. 86956. This value of inputcurrent has teen plotted on the curves of figure 13. Thereforeit is possible for a given K and C to de4termine the length ofcable n that will give the minimum power attenuation.
4.3. 17 The fact that minimum power attenuation is achieved when the totalresistance equals the load resistance has been confirmed by mini-mizing expression (r) for power attenuation. The following expressionis the result and gives the length which will result in minimum powerattenuation in a double unit;
(t) []R K+[MINPOWER ATT:.+C
The corresponding expression for a single unit is -
(u) [n.IMI POWER ATT ZRal K1*
It should be noted that the length required for a double unit isone-half that required for a single unit if the load, the resistanceper ft. of the outer conductor, and the resistance per ft of theinner conductor are identical in both cases. The same conclusionmust be drawn when comparing figure 6 with figure 5.
4.3. 18 To determine the absolute minimum power attenuation for a par-ticular K/C, expression (t) may be substituted into expression(r) and expression (u) may be substituted into expression (s).Utilizing expressions (f) and (g) and using primes to distinguishbetween values in the single unit and the double unit, the expressionsfor minimum power attenuation become -
tv) MIN POWER 1 oATTENUATION !S0 log I 4 + 1)+ 4( + j
DOUBLE UNIT __ _
(db) fKs
(w) MIN. POWERATTENUATION = 10 log I + + 4 [ I+1SINGLE UNIT + ) N
(db) IK-is,
4.3.19 If the load, the resistance per ft. of outer conductor and theresistance per ft. of inner conductor in the single unit and doubleunit are identical and the double unit length is half that of thesingle unit length, the minimum power is the same. This is theonly point at which the power attenuation is the same because atall other points expressions (r) and (s) must be used. Again thisis confirmed by comparing figures 5 and 6 which emphasize thepoint that the total length used in both cases is the same and thatthe double uniFhi' half as much wire in each branch (see figure 4)as the single unit.
4. 3.20 Additional restrictions on the relationships between the circuitparameters are imposed by the cable geometry (see figure 7).Since RF attenuation is a function of outer conductor thi estK= in.), a relationship between the grouped parameter 0 theresistance per foot of the inner conductor (C), and tK i31 erived.Since the coaxial cable consists of an inner conductor, a layer ofinsulation, and the outer conductor, the cross sectional area ofthe outer conductor may be expressed as -
(x) A K =Tr(r 32 - r2 )
However, r 3 and r 2 may also be expressed an -
(y) r 3 =rl + t +tK
and -
(z) r. r I + t
-10-
The resistivity of the outer conductor may be expressed as -
(aa) PK = KAK
and the resistivity of the inner conductor may be expressed as -
(bb) = C 1Tr
Combining results from expressions (x) through (bb) and rearrangingterms, the following expression is derived -
(cc)[]
where in the interest of brevity -
(dd) M =7rtK (t + tK)
(ee) N = 47r PCtK2
4.3.21 The units of resistivity Pare ohms - in. 2/ft. so that t and tK arethicknesses in v¢jhes and C is ohms/ft. Exp ession (cc) makes itpossible to plotgas a function of C with t. /J and tic as fixed
4" parameters. F gure 14 is a plot of this expression when tK is fixedat . 004 in. wgll, VCG is fixed at the resistivity of copper, PK is fixedat 5. 197x I0 "- as the resistivity of 0Q% iron, as specified by thesupplier, and insulation is fixed at . 001 in.and .002 in. providing thetwo curves showr. The plots of this expression in previous reportsgave the resistivity of 99% iron and SAE 1010 stel as being the5 same.Actually the iron has less resistivity (6. 614xI0 vs S. 197x10").These physical properties have not been confirmed.
Attempts are being made to tighten control of the physicaltolerances on the cable geometry parameters so that the circuitcharacteristics, i.e., output current and attenuation, can beconfined to the narrowest practical limits.
tK r3
t
r
Figure 7
-II-
4.4 Testing
4.4. 1 The evaluation of the eight groups of RIG devices was done inaccordance with specification L-19910-67 (see appendix) asfollows:
a. Io determine power attenuation from a frequency
range of 200 cycles per second to 1 megacycle.
b. To determine the DC attenuation of each device.
C. To measure the DC heat rise of one device in each group,varying the DC Xower input until a maximum surface tem-perature at 300 F is obtained.
d. To note RF attenuation capabilities at 10 and 100 megacyclesof one device in each group with varying RF 9 ower dissipationuntil a maximum surface temperature of 300 F is obtained.
e. To determine environmental resistance under conditionsspecified in the L-19910-67 specification. (See appendix forcopy of specification and addendum.)
4.5 Test Procedures
4.5. 1 General - For all tests the RIG devices were terminated in a"75 irm resistive load. The load resistors were constructedusing the methods given in MIL-STD-ZZ0, "Method of Insertion -Loss Measurement for Radio Frequency Filters". The sameload resistor was used for all measurements on a given serialnumber device.
4.5. 2 Voltage Measurements - The voltage level into all devices undertest was held constant at 0. 5 volts RMS from 0 2 to 600 kilo-cycles and 1. 0 volt RMS from 700 to 1000 kilocycle*. The outputvoltage across the 0. 75 ohm load resistor was noted at testfrequency points from 0. 2 to 1000 kilocycles. All devices werethen reversed, end for end, and the test points repeated withthe same input voltage levels applied as stated above.
4.5.3 Impedance Measurements (0.2-100 KC.) The signal generatorvoltage into the bridge for all tests was 0. 5 volt RMS from0. 2 to 100 kilocycles. The Stoddart Model NM-1OA receiver wasused as a two terminal voltmeter-null detector from 20 to 100kilocycles. Impedances were read with the devices terminated in0. 75 ohms resistive. The devices were turned end for end and theimpedances were repeated throughout the same frequency spectrum.
4. 5.4 Impedance Measurements (100-1000 KC.) The signal generatorvoltage into the bridge was as follows: 0.5 volts RMS. 100 to
4. 600 kilocycles; and 1.0 volt RMS, 700 to 1000 kilocycles. Thedevices were terminated in 0. 75 ohms resistive and the impedanceswere read from each end of the devices.
-I2-
4.5.5 DC Attenuation Test - The volt-amp, method was used to determinethe power into the device. The voltage developed across the0. 75 ohm resistor was used to calculate the power out of thedevice. The power level into the device was held to a low value toprevent the effects such as resistance change due to heat frominfluencing the DC attenuation tests. This was done to correlatethe data with the low frequency RF attenuation tests whichwere also performed at low power levels. DC attenuationtests were performed on each device with power applied toone end and then turning the device end for end and repeatingthe tests described above.
4.5.6 DC Heat Rise - One device from each group was subjected toDC heat rise tests. The devices were terminated in a 0. 75ohm 100 watt wire wound resistor. The power into the devicewas applied in increasing steps. The temperature on theouter skin of the device was monitored. The difference in thepower applied and the power consumed in the 0. 75 ohm resistorconstituted the power dissipated in the device. The dissipatedpower was increased until a maximum of 300°F was recordedat the devices skin surface.
4.5. 7 RF Test (10 and 100 Megacycles) - The RF power at 10 and 100megacycles was applied to one device of each group. Thedevices were terminated in the 0. 75 ohm resistive coaxialresistor. The input power level was established by observingthe incident and reflected power on the MicroMatch meter. Thematching network was adjusted until the reflected power waszero or to a minimum value approaching zero. The VSWR forall tests approached a value of 1. The heat rise on the skinof the device was noted by a thermocouple attached to a fillhole as in the DC heat rise tests. This temperature rise wasrecorded at varying power input levels until a temperatureapproaching 300OF was again noted on the skin of the device.The output voltage level was also noted across the 0. 75 ohmresistor at each frequency and at each power level. Thisvoltage was read on the Empire NF-105 field intensity meterset on the carrier function. The instruments output meter wascalibrated for full scale deflection as a two terminal voltmeter.
4.6 RF Test Results
4. 6. 1 Figure 8 is a composite curve of all types of RIG devicestested to date. It includes both double unit and single unittypes. Also included in figure 8 is the attenuation curve forthe .0015 in. 1010 steel, L-19910-36 RIG tested in Phase I.The tabulations of the attenuation vs. frequency of all thedevices tested are included in the appendix (see Tables Vthrough XIII).
4.6.2 Figure 9 is a comparison of 1010 steel, 99% iron, and No. 42alloy, assuming a constant material wall thickness of .0015in. The 1010 steel gave the highest RF attenuation with the99% iron next and the No. 42 alloy the least.
-13-
4.6.3 Figure 10 is si mil;r to figuire ) exc(pt that the wall thicknessin the case of 11110 steel, 99% iron. and 42 alloy is assumedto be .003 in. These results show the 99% iron to be thesuperior in RF performance with respect to the 1010 steeland the No. 42 alloy.
4.6.4 The apparent conflict between figures t and 10 can only beattribtd to the inability of accurately determining the actualtube wall thickness of the .0015 in. material. The toleranceof ± .0005 in. could make as much as a .001 in. discrepancybetween any two materials. For this reason the 99% iron isbelieved to provide superior RF attenuation.
4.6.5 Figure 11 is a comparison of various wall thicknesses for RIG'smanufactured from 99% iron. Both the . 004 in. and the . 005 in.wall thicknesses meet the 40 db power attenuation requirementsat 100 kilocycles.
4.6. 6 Figure 12 compares various wall thicknesses for No. 42 alloymanufactured into RIG devices. None of these devices metthe 40 db power attenuation requirements of 100 kilocycles.
4.7 DC Attenuation Results
4.7.1 The DC power attenuation for all RIG devices tested is includedin Table II of the Appendix. A summary is included in Table I.
4.7.2 The only device to approach the DC and RF attenuation requirements
was the unit having the .004 in. 99% iron wall in the 66-1 groupof Table II. The 66- 1 group had a DC power attenuation of 8. 1 db.
4.7.3 The spread between the maximum and minimum values in DCattenuation as noted in Table I may be due, in part, to the factthat the cable lengths were not exactly the same length for devicesof the same construction.
4.8 DC Heat Rise Results
Table III of the Appendix gives the results of the DC heat risetests for each group of RIG devices. None of the single unitdevices was capable of dissipating 10 watts of power prior toobtaining a surface temperature of 300 0 F. The -66 and -66-1groups were capable of dissipating the highest power levelswhich was approximately 8 watts.
4.9 AC Heat Rise Results
4.9. 1 All single unit devices were capable of withstanding similarmagnitudes of AC power at 10 and 100 megacycles as thoselisted in the DC heat rise results. No device malfunctionsoccurred after I hour exposure to this heating.
4.9.2 No double unit devices were tested for AC heat rise due to thedifficulty encountered in matching the double unit devices to thesingle ended transmitters.
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4. 10 10 and 100 Meg, . ,Ic Att nuatio,
Table IV of the Appendix shows that all devices testedcontinued to attenuate RF power at these two frequencies.Where the detectable level across the 0. 75 ohm resistor fell belowan indicated I microvolt level reading, any reading obtained wasconsidered inaccurate.
4. 11 Firing Current Response Time
Two -66-1 RIG devices were tested for response time by monitoringthe delay time between application of power to the input of the deviceand development of 1. 5 amps firing current in a . 75 ohm resistanceload. The delay time was approximately . 7 milliseconds. The twounits tested were s/n 153 and 157.
4. 1Z Environmental Testing
4. 12. 1 The following RIG devices were submitted to the Engineering TestLaboratory for environmental tests:
Part No. Serial Nos.
L- 19910-49-1 71 and 73L-19910-49-2 92 and 94L- 19910-49-3 35 and 45L-19910-49-4 18 and 19L-19910-49-5 117 and 118L-19910-66 54 and 62L-19910-70 127/128 and 133/134
4. 12.2 Each of the RIG devices was subjected to the following environmentaltests in accordance with Specification L-19910-67 of issue in effecton date of inception of these tests.
1. Initial Resistance and Inductance Measurements (3.4. 1 and3.4.2.)
2. High Temperature Tests (4. 1)
3. Low Temperature Tests (4.2)
4. Thermal Shock (4. 3)
5. Vibration (4. 6)
6. Shock (4.7)
7. Humidity (4.4.)
8. DC Temperature Rise (4.8)
9. AC Temperature Rise (4. 10)
10. Terminal Pull (4.9)
11. Salt Spray (4. 5)
4. 12.3 Each of the R( ,, :, (r rnr(. ;ill of the rquirements of theforegoing tests vith the following exceptions. Unit serialf number 73 did not perform satisfactorily fluring the AC Tem-perature Rise Test. It appeared to have a short in the windings.The unit was disassembled at the conclusion of all the tests.The coaxial wire was unsoldered and resistance measurementsof the center conductor and the outer conductor were made.The coaxial wire was re-soldered at each end and resistancemeasurements were made and compared to the individual valuesof the conductors. There was no indication of a short in thewindings. Further investigation of the discrepancy failed toreveal any additional evidence of the cause.
4. 1Z.4 Unit serial number 118 exhibited erratic resistance readingsfollowing the Humidity Test and the inductance measurementscould not be made. This unit was subjected to the balance of theenvironmental tests and then submitted to the ResearchLaboratory for investigation.
4. 12.5 The two pin connector on the output end on each of two of thedouble unit RIG devices became damaged during testing. Inboth instances the damage resulted from shearing of the smallkey in the shell during tightening of the coupling ring. The pinswere sheared off flush with the face of the insert, rendering theconnector useless. The key in the shell of the receptacle isformed by upsetting the shell wall and is apparently far too weakto adequately perform its intended function.
4.13 Retest of RIG 118.
This test consisted of impedance and voltage measurements toverify the results in paragraph 4. 12.4. The device as receivedwas erratic in behavior with respect to impedance measurements.The open circuit input impedance of the No. 2 end appeared tobe twice that of the No. I end. The device was retested again aftera lapse of several days. The device then tested normal for bothimpedance and RF measurements. Striking the device in a sharpmanner produced no erratic behaviors. The device is still underinvestigation with as yet no cause determined for the origiralmalfunction.
5.0 Conclusions
5. 1 The double unit circuit as shown in figure 4 is the same circuitas shown in figure 5 when it is perfectly balanced. This circuitis basically the same as that of the single unit shown in figure 6.Therefore the design curves shown in figure 13 are the same asthose for a single unit except for one feature. The abscissa(the nC scale) is multiplied by a factor of I/Z in the new curves.The conditions for minimum power attenuation were also inves-tigated for both single and double units. The length n that gives
-16-
miinimum attenuation is given in expressions t and u, paragraph4. 3. 17. The minimum power that can be attained with a particularset of parameters is given in expressions v andw, paragraph 4. 3. 18.These conditions are achieved when the load and the Irnetwork arematched; i.e., when the combined input resistance of the 7rnetworkand the load is equal to the load resistance.
5. 2 The test results show the . 004 in. wall 99% iron (group-66- 1) devicesto be those which most nearly comply with the general requirementsfor the RIG.
5.3 The environmental testing resulted in erratic electrical behaviorof two units but there was not sufficient evidence to warrant attrib-uting these malfunctions to environmental stress.
6.0 Recommendations
It is recommended that the . 004 in. wall 99% iron single unit designbe manufactured for Phase III of the program. This recommendationis based upon the general requirements and conclusions as stated.
41
-17-
ALLL
AV
It
I It
fifl-
A ll It
i Nit I I I -4TE UFTA
T15
Ln LALn M
W AI : W
0
U) P$> 0 L. I I fill IZ0 i+H
1 H z
c; P. I Pw z 4-
3 w 64Go ; 41,
.1c 0 0z
1 I-j I 1IZl
7TITTTM TH TTT1 I I I
M M:
4-
0 1 7-U! Dori o I
9a) Nol.LynNaiLJLV
RIZ
Figure 8
-18-
........... .... l i tT-AM 1. f. 1.
U TT
. ...........
- ------- 1 1 fT--- --------------M .........------ ----
t
T1T-T T
z 0 -TTf- m w Ln Ln
t- V Ln f" Ln M \1 V
z
Al A
a 0
1 too$ 0 t;> 0
44 Jill I Iz to0E, 0
z
z + T7.>
C;H31
A 0 0
i 94,
z
If I I I %Z
1 111111 TT I -I FM T 11111 1 1 i H
tit ILA 0 1ut d 001 01
af NOIJ.VnNa.LJLV
Figure 8
-18-
TI'- rr~r~rrrrrrT~~ 'T -- T- T}]
T. 4 .
7 4-4- 4
7 4 --
z
a13 .V .. .... ...
z Cn
. . . . ..
5- Z
04 f" .
T
......... ... ........ ....
.. ... ...o. .. .
;.I(Qr) Noi.Lvn~ai.v
Figure 9- 19-
I, I T
it )N IlNll ll
FiIr 10U
a-20
4.W ':- 'r-
4 0 co0
3 -
a r- ini
U) 0> -i
7
0 4
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aa
I -- I, O
a fla
In
F i r I I
* - i:~j 01 lO'1 0
to N-
41P a A 14
AN,
2 N-
-------- ---
in fn
coo
Z
U04
>
w jjz
0
U--------------------
-- --------C;
I -----------
In ------ - -> 0 110
t
L . ........
-T'TF'F
FITI-I
Ino cl 01urr-& 00,101
(9U) NOI.LVnN:I.LJLV
-A I-1-- I I I I I L I I I I 14-1-LI J I IJ 11 -L
&
Figure 12
Qz_
0 000. (3lnc
0 .. J IT _______
2 -- --. n
o co
100.0
4
'-4-
Figur 13~23-
100. ITTTlnlTmT1 NT -1'-t144 r
IIPK 5.197 xo-5
A) t .001. t( z .004
B) is .002, t K x.004
6 ~ r . ~ 4 4 j44-_
10L 0
4iFigure 14V)-:4-
*2 I<
<I
ccI~
~j~j Jli -41. +
-~ eijt
Figure 15-25-
CIO
I-, I
NN
Lj)
C,
226
ID EDi o
IIjLI)
II4
I a ilon I
o.
4 24
J:!
-27--
Ia,
444
Figue 0
028
U
Appendix
Contents:
Formulae
Tables I through XIII
"A Note on the Use of Attenuators inBalanced and Unbalanced Networks" byWing Commander R. I. Gray
Qualification Test Specification L- 19910-67Addendum to Specification L-19910-67
Report Responsibilities
Bibliography
Appendix
Formulae
Computations - Power and Voltage Attenuation .2 to 1000 kilocycles
Power attenuation in db = 10 log 1 0 PI
PZ
P 1 = power into the device in watts
P 2 = power out of the device in watts
PI = (Ein)2 where Zin = R a J X
Zin
Rs is the bridge measured resistive component of the inputimpedance in ohms, with the device terminated in 0. 75 ohms resistive.
Xs is the bridge measured inductive reactive component of the inputimpedance in ohms, with the device terminated in 0. 75 ohms resistive.
P real E 2 R
(RS) + (Xs) z
P2 real = where R is constructed to be 0. 75 ohms resistive
RL from . Z o 1000 kilocycles
Therefore, the power attenuation is equal to:
(Ein)Z RsRL
lo0 (Eut)- [Rs)- + (Xs)Zj
Ein Rs RLdb= Z0 log 10 ---- + 10 logl 0 Re +
Eou t (R8)2 + (X9)2
Limitations of formula:
at low frequencies, from . Z to 10 kilocycles, where X is smalland R is less than 1 the power DB appears to be greater thanthe voltage DB. This is due to the fact that the 10 logl 0 factorof the formula is greater than 1 and is positive.
Appendix
-I-
Computations - D(; AttenuationP1{"DC power attenuation = 10 lOglO
PI = Ein x In
P 2 = (Eout) 2 where RL = 0.75 ohms
RL
DC attenuation in db 1 0 logl 0 Ein x Iin x RL
(Eout)2
Appendix
-2-
t~P- 0 PwN0~
- N 0 tn IA
* N 0 I10 to 0 0 * -
10 1 0 N . . * 0%- . --
tn co 46 fEin0 60 *00
V N -0
* 0 - 0 n
~ 0 N 0 C
46 ~ O f" * *.
S.SO
0 00 0 R'
f~I fa 00..
C3 40 *% u
z t
Apeni
6J.~ -3-
'I 'Alt. 11
TestInstumen~s)Da to
R Load
-R -.S9k0.MN-(91OOP0.6VLMW WVx
_? __ 6.016~ F __ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _
______ __ _ __qc-"e- I,
q4 . 3 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
_________~~ ~ ~ 1 ______ '1 _____ _____ IZ _____ ____
,______ ______ _ ____ ______ ~ GOT".B2 q~t _ _ _
49- __ _ _ __ _ _. _ _ _ _ _ __ _ _ __ __o_ _ _ _ _
to_ __ 4._ _ __ _ _ 12 4 _ _ _ _
___ __ _ _ _ _ 4 3 __ _ _ _ _ __1 0-1 qq
______ 9-2 01___ _ __ _ __ 00 _ _ __
_____C6 IRS.16 _ _ _ _ _ _ _ _ _ _ _ _
-4
Table III
TEST D.C. v t . % sr;r. PAPA,. rr
TFST SPECIMEN DATE TEMP. JRH.
TEST INSTRUMqENT(s) TESTED BY
APPROVED
__-pow,_ t, j o3ZT 6%U~~~~~~~~~~~~ P-S11 61P SSI r.TM 1AKX f(U-j( -%1T"J
b( I ?8" 66ati k'o l
40 112.4 i q _ 3.o- I i'ts 88&I ?q , &K q ' 1.116I 23.. q0
IL 9 1 acv 7 99 'IT.- I-i's zg8 9b___ __ ___ _ '.40 300 1___
2.14aI 1o S 4 10 __ _ 65__ ____ 0___0
4.1L I4 qC _4__ 94; 3.0+ I3 102
6.11 age. q- St.18 Z33 1o_
__- _T.as ago I _
sS 4J J.QSLf I o 'g. pq 300 914Z.S0o3 16e -10 _
&5 G ___ 1"___ 510%1-14 90&966.10 ,6 ?o ?.q3 1ES se
____ _ ___ '.D'4 13.!
Sim k'i O.T10 16 '13 _(.06_ 10'I 90
2696 "0/3 3 IM.O 2&9S i.s,-t.g S T -?16 I ct6.10 U-6 as1. IS 2B 3 qo
,51011I3 O.'!S 108 F3__ __ _ _ _ _ __ _,80 113u "rqs 6O 1I___ __ 3.0fl6 It'j 76 _ _ _ _ _ _ _ _ _
_____ 's .5.2 ]F 2,56 __ _ _ _ _ _ _ _ _ _
LABORATORY DA7A SHEET SCINTILLA DIVISION, SIDNEY, N.Y.1
4Appendix
72-354
'IJable TV
UTEST -' .PARA. rrLt
TFST SPECIMEN DAETM.RH
T FS T I N ST R u mrN TC TESTED BY
APPROVED
__4 __Z 91 0 _ _ _ _ _ _ _ _
______ _____ a 6 _ _ _ _ _ _ _
_43 0 30_
0 LES-S THr 4%) V___N O DEC1 CTA1LE. 0AT1PttT __________
LABORATORY DATA SHEET SCINTILLA DIVISION, SIDNEY, N.Y.
Appendix72-354 -6-
res &or ~~6e4r-AAr4 Spec. Pams.
Test InstrumentT'u Date
'z-/ 99m ~- .. '9-/ 6 R Load
o=-jr EI 1 7/ .51,ovz ______Av v
~~2~ 7~_
'/ 7, & /, /& 7___ ______
_____ 1_ 1.01 % / ~ Z~ V9_ _ _ __ _ _ _ _ _
_!Z 2 L ___ -? 1,g
_sl //P - 9,3-,__-d~ j aa±_ _o 4
56-a__I . . 40 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
A66__ .7.6.c S __ __ ____
*loI -/3~ ~2.-5- a
L40,0. eiZd .2' 3067 - - ___ ___ __
go 7/__ 4a/. 70 .3. __ _ _ _ __ _ _ _
'es 675 xf"' -__
-7
Test pecPara.
TestInstumen~s)Date
t - Cl"'kk C - l I- IR Load
V_ __ i*t-' A..L8 s.2E C1___ ______ __z_____, S
±&a. S 61? 15 ___S
15 11~ JL5 1 I±t T-1
'1,() L-.4L L6 . 6 441 _ _ _ __ _ _ _ _
1(;.v l&1 .i.j,______0 9t.131 F.6 Ib.i% i. i _ __ _ _ _ _ _
i0 14 __ _ _ __ _ _ _ _ __ _ _ __ _ _ _ _
30.0O i.Z1 12_______ ___
.......24.2. o~~.3 '.26 I S.__ __ _ __1__ _
'zCv" *)'Z. ' z 'Z. I 21.L L± S- -
a_4-1 C-1M 33.90 V& -4 -
-
6C'O.) 4-4.l73
FcO.O 4q-' 6 4R. W. 6
Test -Pars,
A'F~~~~~=O /-4'> 4 ~ '(
Test Instrument(s) Dato
gge o _ 7__?__7_f
Z/ 6/1 L ~
171 9, -d _ _ _ _ _ _ _
62740__5 4,111. ___13 A.2__
/0 94 7. -Y.3__ M.____
2~~~Z~9 dl ~ __ _ _ _ _
y~~6~ /tb3 7/ __47_ -P_ __ __ _ _
/43 ____ _S_/_2__
/I&Q m ~ 116, 1-, 1. 3 __71_
7-O /0 _ _ _ __ _ ~ A/c)O.1) ~~ ~ ~ ~ ~ rle /9~ ~/./ /. Y _ _ _ _ _ _
~~~~ 0,_ __ _ _
- 6' _ _ _ _ _ _
<. Teat /%I Po 0 pO Par.,
0 / ec~iZ~oR Load
j .9f, Soo _ __9- 40 4 p -Y
A__ IS f.~ A'S_ ____
.. LL4.62 ./~ 2....h ' _______
49X e -VL.1 ~ _ _ _ _ _
'Of . &F4 . 79 0/ d, 7__ 9______
f. 0... -?7 gf-tL S7 7 .3- ____ ____
4- l 4,9 LZ if, 17 V, 7 ___ ____
ao-o :z -?,/ :730 _-,_Of_-6_.__07
V. Q' /.I& 9 S.7 1 ____
/or-,j 49. o3i7 9.S-7 1?__)__9_/a._e
SWA- 1610 Ii "I
-19910 /Ir. / A-10&
Test-RY.Pama.
TestInstumen~s)Date
L R Load
I___ ID 6. .3 * 3 a______
'4.0 .j &A s. 1. 14 1,,SS
7.0 1,07- ____ ?-- 17. 17, 41±
0.0. .~j4 j Z!;.....4& 101 'IT b I .. L
zc( 7,617aL .So~± IT, 5 SO sq.___30.0 1) 17. 10 13J.9(__
60.0 SA___ -q.__ ZZ -C-17 100s
7810 .L?1. %S___ ..3l.~ AI 11 .3_It____
1 . t S, q'.99& 3 ~ ~ ___
-T. o,2 o3 1--1---
10010.~~~~) n11 dix101, 17
lig~go K.36 12IL l-1
Test F ara.
Test Instrument(n) Date
LA IE it\) Load=
- -r- 8 -
______14._S4. __0_!__1_14__ 1-t 10_S.__
-z6 - L,~ __ _ _ 7I-.03T ('7t. o_ _ _ _ _ _ _ _ _ _ _
3.0 ~ ~ i O.O ( 1.5 F2(4,o j____ to Is,___ 7____ ___
5"0 ___ __ 6____ ___ __ __ _ _ _ _ __ _ _
60.0, 2( I __ Z'Z Ajfji- I_ _ _ __
8o~o ?-1. __ __ U .1 _ __ _ _ _ __ _ _ _
Z).O -2Lq U __ __ V_ __ (____1 ?A.___
3.0.c) 31. .e -(. 2 .; ._ _ _ _ __ _ _ _ _
40.0__ 3G.4;L 31.6 _______3 .tS-06 .3± _______ I_ __ _ I_ _ _ _ 3&___S
90.0 __ _ _ _ _ _ __J. _ _ _ _ _ _ _ _ _ _ _
'40.0 __ _ _ __ _ _ __ _ _ _ _ _ _
(400.0 __ _ ___ _ _ __ _ _
Appendix
Id2-
Table XI
T esat Spec.0 Pars,.
TestInstumen~s)Da to
L-- qctD -R Load
EQ S~ (6- 1~ Va IS
R c.~c. (be) OM___ _____ __________
0.200 q-29 9____ q~a 9_____ __1.1
___0_ 12.546 12.31 __ _ _ Zo9 _ _ _ _
6.0 _ _ _ _ _ _ _ _ _ _ _ _ _
6.0 _ _ _ _ _ _ _ _ _ _ _ _
* I~6.0__ _ __ _ _
CV. 0 _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _
W.0.o _ _ _ _ SOO+ 2 .I ZIO~ c~ _ _ _
?0.0_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
__ _ _ __ _ __ __ _ ' I. ~ 'oc * . O _ _ _
- -
Appendix
-13-
T1)lv XII
Lpoc. Para.
rest Instrumont(s) Date
- , - //-W~ R Load =
,'/, * (7Z.. t'/,,i' , , ' ~' 5.'e,a' S#g,& ____
6 6re' Y .. f.7 91, ,Z ,.-77 V, 4/l_. S 57 9. fi. _ _ _ sa q,_77/.o:/ 7 , ,?,S84 __ _ ____- _ ",4 SY 9 ' ______
- 417 V. Vs-/1Y, 6--5- 9__0___9
3. Q. Aly'_. /A. ' // ZA 0_ ___ _ ,/__ _____. _ /13 //,:,
._ ., ih?'7 // 1 7 //, 7,0e0__5_ '496 A 7 ____
7_ __ ______ A0.9 '/-.2 __ _
_,___, ___, L," .i~ .o- ..2 .L // ___ _,
1,6-, A 7 / 7,5- .1 /,$, 002
, r -.qm7,10 .7o 4 ,9 1Z 93 /.0 /7,.a10 ti___'.t', /1,7 41.3 /S73lf _, _
la ..- / el H,/ e 7/. ,, _2
70, _7 1_,__ _1. * - 80.. ca /.
_ e_____, V,7 /, s /, 1___ _____- - __.,/,_._ ., .57y _______o/3
4 04, 6 9 .,".. .3 :._1, _ _,_.__
i.:___,__ .3'6:_ /.J . ___,_"_ o,46.
_______) - 7. 7 _ _ _
.olo ./) . ,..' 7 7,,- ____
_____,_ 7o_',.36 . / L __;__...
/o, eJ . 6:-d 770 Z _.. 7 Y, -- - ;/,/,7- ,-
Appen('Iix
- I1 -
Table XIII
Test R,,vt.i~Z Speo. Par&.
TestInstumen~s)Date
L-~~1 R Load
tc0a6AF -' U~te-mit i- j 4bo A-4 stv%6 %-Z__________
E2 b~ 462 __i f2w -a-, fm Cf. AS__ ____ ___
4. oo 1, ?2AL t(.0 to,__ _ ____ ____ ____
G&....2.....LZ it .m tO ~ ___ILL
(2.0 ~~!~It If IZ t.I _ _ _ _ __ _ _ _ _
,____ 'it 11__ __ __64_ _
9JL2 -i L 12.A17 12.1 11__ &_ _ __ _
Tc 17-.23 12,~15.. 11.2 __ _ __ _ __ _ _ _ __
V. ~ L16 . (C 1 11 4.. __ _ __ _ 0_ _
Go .i..AO -1LSA .IA Iq A __ _ _ _ _ _ _ _
60,Q Zj 07- S' ?5Q,_ __ _ __ __ __ _
Ifo 71 0 :U,17- 'It.12 ... iLQ __ _ __ __ __
1000 17,. I.S L___1 _____ ___K
200 -4AL isL~ N.3A 31 . ML. __ _____
-. d.% M 4X.I - m.
Appendix
-15-
A NOTE ON THE USE OF ATTENUATORS
IN BALANCED AND UNBALANCED NETWORKS
by
Wing Commander R. I. GrayU. S. Naval Weapons Laboratory
Dahlgren, Virginia
1. The purpose of this note is to analyze the problem of usinga pair of "Radio-frequency Interference Guard" atten-uators in a balanced two-wire circuit as compared withtheir performance in a co-axial circuit.
2. A well-known theorem of network analysis states: "Anypassive 4 - terminal network may be completely represented,or replaced, at any frequency by a suitably chosen "T" or"Pi" network (or any network having at least three independentparameters) so far as external currents and voltages areconcerned.
3. Unbalanced or Co-axial Network
The R.I. G. and its associated load EED may be representedas follows:
FIGUR.E I
(1) II (ZI + Z)- 1 2 Z2 = E1 I Ii( Z
(Z) 1z (Z 1 + Z + ZL) - 1 Z2 = 0 Z+ + Z
1 2 2 1 2 L)
Zi= (ZI+ ZIi il IZ)-Z I + Z . + Z L
= Lz1 +zz- -Zl z+ZI
Hence, the attenuation for the unbalanced network may bestated as:
[Pin Re (E l 11) Re (Ii12 Z in)
C L -- 0 I g ... . .. R e Z inPout Re E 2 12) Re (122 ZL) ZZ Z
(Z l + Z? + ZL) Z + Z2 ) (Z l + Z + ZL) . Z2
Z2 ZL
NB: Real parts of complex numbers will be understood toapply in this and all subsequent expressions for attenuation
and we note that, if ZL « Z1 + Z. the attenuator approx-imates to a "constant current' source and CL =.e K Z4(e. g. if we halved the load resistance in a purely resistiveload we would double the attenuation approx. )
4. Balanced Network
Two identical R. I. G. s and their associated load EED may3 be represented in a balanced two-wire circuit, as follows:
FIGURE 2
0 Z Z ! . ... .
E I -ZL E212 Shield, Ground or
o, '---- h image plane
It is clear that, because the network currents are equal andopposite in the shield or ground plane, which in assumed tobe of zero impedance, this dividing line between the twohalf circuits may be ignored and the network solved for 1and I 2 as shown above. It will be noted that the principleof "inmage circuits" has been abused by the use of a load ZLinstead of 2 ZL.
(1) I1 (2Z 1 + ZZ2 ) - 12 P2ZE) = El
(2) I2 (2Z 1 + 2Z2 + ZL) - I1 (2Z 2 ) = 0
E= +i21 + ZL)
- L2z1+ zz) 422Iin 1 2 Z i
Hence, the attenuation of this balanced network may bestated as:
L 10 g _1_P . R e ( E l I ) e R e Z in
SPout Re ( E 2 Re(IZ2 ZL) (z1+ J ZL
z ZLSZ 1 + Z 2 (Z I + Z 2 + 2 )" 2 ] (Z 1
+ Z 2 + )Z2 ZL
and we note that approximately : L 2
But it is important to observe that, this factor of 2 is dueentirely to the fact that we have failed to provide each halfcircuit with its original load impedance Z as in the un-balanced system. This is readily checked, by writingZL = 2 ZL instead of ZL in the expression for (B when
CL B- =
(I u
It is interesting to note that precisely the same effect isobtained in the unbalanced circuit if we halve the loadresistance ZL.
5. The input impedance ratio:
-3-
(B) + z) ( iZ + z](zI + Z2 + ZL)2 -+ ZZ. .+ 2. ... .
Zi~+ [(z 22 (Z+ + Z? +Z
and if Z <-< Z + Z this ratio is approximately 2. Againwe note that if tle loid impedance is doubled in the balancedsystem, this ratio is 2 exactly.
6. It is also clear that the power rating of the balanced systemis twice that of the single circuit. The situation is analogousto that of resistors or lamps in series or parallel. It isimmaterial whether they are connected in series or parallel -
provided they carry their rated current and hence have theirrated potential difference across their terminals, they willeach dissipate the rated power.
7. Conclusions
If two identical co-axial networks containing the R. I. G. areplaced side-by-side to form a balanced system as shownbelow each half circuit is entirely "unaware" of its neighbor.
- -] FIGURE 3
R. 1. GE. E. D.
This schematic diagram represents a double, shielded,co-axial system but it may equally well be contained in acommon shield provided the e-m barrier of the R. I. G. sis brought out to the common shield. The system can thenemploy shielded, 2-wire (twisted) circuits. Under theseconditions, and provided the load consists of 2 EEDs inseries or of one EED of twice the impedance of the originalthen we have: -
a. Twice the power dissipation capacity
b. Twice the input impedance
c. The same attenuation as in the prototype unbalanced circuit.
8. However, if we use the same load EED in both the unbalancedand the balanced system then we have the attenuation andimpedance ratios given in the previous analysis. The powerdissipation capacity of the pair is still double that of a singleunit.
(R. I. GRAY)
10 November 1962 Wing Commander- 4-
CODE 77820
I _ _ - -;;SPECIFICATION L-1i! Oi-C,7L- ~1 -TEST - SHEET I OF I
SCINTILLA DIVISION -.up Piwgm 110u SIDNEY. N. Y., U. S, A.
QUALIFICATION TEST SPECIFICATION FOR RF ATIENUATOR-SINGLE UNITFOR R & D PROGRAM
1. SCOPE
1. 1. This specification is an adaptation of MIL-E-5272C (13 April 1959)to the specific requirements of an RF Attenuator.
1.2. This specification establishes the requirements and procedures forelectrical and environmental tests for the RIG device. Proceduresprescribed herein are to be utilized in subjecting the RIG device tosimulated and accelerated electrical and environmental conditions.
2. APPLICABLE DOCUMENTS
2. 1. The following documents form a part of this specification to the extentspecified herein.
Specifications
Standards
Federal
Fed. Test MethodStd. No. 151 Metals; Test Methods
(Copies of documents required by contractors in connection with specificprocurement functions should be obtained from the procuring activity oras directed by the contracting officer.)
CODE 77120
SC*NI1UA DIVISIO M CHANGESIDNEY. L. Y, U.S& A.I
3, GENERAL INSTRUCTIONS
3. 1. Test Facilities
3. 1. . General - The apparatus used in conducting tests shall becapable of producing and maintaining the test conditionsrequired, with the equipment under test installed in thechamber and operating or non-operating as required. Changesin test chamber conditions may be the maximum permitted bythe test chamber, but shall not exceed the applicable equipmentspecification requirements.
3. 1.2. Volume - The volume of the test facilities shall be such thatthe bulk of the equipment under test shall not interfere withthe generation and maintenance of test conditions.
3. 1. 3. Heat Source. - The heat source of the test facilities shall beso located that radiant heat shall not fall directly on the equip-ment under test, except where application of radiant heat isone of the test conditions.
3. 1.4. Standard Conditions - Conditions for conducting the equipmentoperational test shall be xs follows:
a. Temperature: 70 0 F + 30 -10b. Relative Humidity: 90 per cent or less
c. Barometric Pressure:Local standard (Correct to 28 to 32inches Hg if so specified in
the applicable equipmentspecification.)
3. 2. Measurements
All measurements shall be made with instruments the accuracyof which conforms to acceptable laboratory standards, and whichare appropriate for measurement of environmental conditionconcerned. If tests are conducted at the contractor's plant, theaccuracy of the instruments and test equipment shall be verifiedperiodically by the contractor to the satisfaction of the procuringactivity.
CODE 77820
SCINTILLA DIVISION 1CHANG4SIDNEY. N. Y.. U. Lk A. 1PRW
SHEET 3 Of
3. 3. Test Sequence - Unless otherwise specified in the applicable equip-ment specification, it Is recommended that the appropriate test sequencebe eel.-ted from 5.1.
3.4. Performance Record - Prior to conducting any of the environmentaltest specified herein, the RIG device shall be given the followingoperational electrical tests.
EKJD DWC. 1 QO. 7-
FIGU 2 I3.4. 1. Using a General Radio Impedance Bridge No. 1650A, or equivalent.
(Figure 1), check the resistance between the input (No. I)in and thehousing. Repeat this check between the opposite end, the output(No. 2) pin and the housing. Check the resistance between the twopins. Record these three (3) resistances. The readings are to berecorded to three (3) places.
3.4.2. Using a General Radio Impedance Bridge No. 1650A. or equivalent,(Figure 1), check the inductance at 1. 000 cycles, between the input(No. 1) pin and the housing. Repeat this check between the oppositeend, the output (No. 2) pin, and the housing. Check the inductancebetween the two pins. Record these three inductances. The readingsare to be recorded to three places.
3.4.3. Make the following measurements and computations with No. I endas the input and No. 2 end as the output.
3.4. 3. 1. Measuring ac voltage with. 75 ohm termination at (No. 2) output
end.
Connect the RIG as shown in Figure 2.
CODE 71820
SCINTILLA DIVISION '7N~SIDNEY, N. Y., U.S&.A. 74 wti mo
SHEET 4 OF
FIGURE 2
oscillator Hewlett Packard Model 200 C-D-ZOC- lOOKC.Measurement Corp. Model 65-B 100 KC-l1MC.
Amplifier General Radio Power Amplifier Type 1233A ZOC- IMC
Ammeters Weston Model 425 RF Meters(0. 1. 5) amp. -2% accuracy.
Voltmeter Fluke True RMS Voltmeter Type 9 10A2% accuracy
Re . 75 * . 02 Ohm resistive load - I1/Z watt - non inductive
Th. input current shall be m- itored and held constant within 10% throughoutthe test.
CODE 77820
SCINTILLA DIVISION CnH.. CANG9
SIDNEY, N. Y. U. S. A. I ISHEET 5 OF
3. 4. 3. 2 Measuring Impedance with .75 Ohm Termination at(No 2) output end.
Connect the RIG as shown in figure below:
OWPE.AAKE jjRjjAE
FIGURE 3
A. Equipment for freq. up to 100 KC.
Oscillator - Gen. Rad. IZiOC-20C- 100 KC or equivalent
Inductanee Bridge - Gen. Rad. 1632A-ZOC-100 KC
Null Detector - Gen. Radio 1Z3ZA Z0C- 100 KC.
B. Equipment for Freg. 100 KC to I MC.
Generator - Gen. Rad. IZlC - 500 KC-50 MC or equivalent
Inductance Bridge - Gen. Rad 916 AL-5OKC-5MC.
Detector - Stoddart N. M.- 10 Receiver 100 KC - 150 KC orEmpire Noise and Field Intensity No-105
Item 1 - G.R. Type 874 to N2 - Scintilla Adapter 21-31114
The input current shall be monitored and held constant within10% throughout the test.
CODE 7762O
SCINTILLA DIVISION CHANG9
SIDNEY. N. Y., U. S. A.
SHEET 6 OF
3.4.3. 2. 1 Take the following reading* and perform the necessarycomputations
1 2 3 4 5 6No. *5% 1Points F req. a-
KC Gx LX RX Ein EoutE E2
1 0.2002 0.6003 0.8004 1.05 2.06 3.07 4.08 5.09 6.0
10 7.011 8.012 9.013 10.014 15.015 20.016 25.017 30.018 40.019 50.020 60.021 70.022 80.023 90.024 100.025 150.026 200.27 250.28 300.29 400.30 500.31 600.32 700.33 800.34 900.35 1000.
Attenuation - db - 10 log 10 P in (Real Power)P out
db:10 logl E 'I RReal+ow1r1
EZ ROR 1.L
CODE 77820
SCINTILLA DIVISICN 107r7aw;4b WW~RAl0N CHANGESIDNEY. N. Y.. U. S. A.
SHEET 7 OF
3.4.3.3. Plot dissipative attenuation versus frequency at each point onsemi-log graph paper.
db 10loglOE R1 (R z+ X ZLE Rt(R, (i+ XL
3.4.3.4. Determine tne dc attenuation with a . 75 ohm termination at(No. 2) output end.
D.C. Attenuation = 10 log1 0 E R 7-E R
.
3.4.4. Repeat all of 3. 4. 3. measurements, computations and graph@ withNo. 2 end as the input and No. I end as the output.
3.5. Criteria for Failure - Appreciable change in readings of 3.4. 1. or3. 4. 2. or 3. 4. 3. shall be evaluated for failure.
4. ENVIRONMENTAL TEST PROCEDURES AND REQUIREMENTS
4. 4. 1. High Temperature Tests
The surface of the RIG device shall be raised to 160 F +0 -10 F for4 hours. At the conclusion of this period and while still at the testtemperature, the equipment shall be operated in accordance with3.4. 1. and 3.4.2. The RIG "-,vice shall then be returned to standardconditions and again operated and ins.pected visually as specified in3.4. 1. and 3.4.2.
4.2. Low Temperature Tests
The RIG device shall be soaked for one hour in a test chamber maintainedat a temperature of -65 F. While at this temperature, the RIG deviceshall be operated in accordance with 3. 4. 1. and 3. 4. 2. The RIG deviceshall then be returned to standard conditions and again operated andinspected visually as specified in 3.4. 1. and 3.4. 2.
SCINTILLA DIVISION CHANGESIDNEY. N. Y.. U. S. A. 0.
SHEET 8 OF
4. 3. Temperature Shock Test
The RIG device to be tested shall first be placed within a test chamberwherein a temperature of 85 C (185 F) is maintained. The RIG deviceshall he exposed to this temperatt re for a period of one hour, at theconclusion of which, and within five minutes, the RIG device shall betransferred to a chamber having an internal temperature of -67 F.The RIG device shall be exposed to this temperature for a period of onehour. This constitutes I cycle. The number of complete cycles shallbe four. The duration of exposure at each extreme temperature shallnot be less than that specified and may be extended to overnight exposureto prevent interruption of the transfer sequence. At the conclusion of thefourth cycle, the device shall be removed from the test chamber, returnedto standard temperature and inspected as directed in 3. 4. 1. and 3.4.2.
4.4. Humidity Tests
With the ends sealed with suitable sealed plug or equivalent, the RIG deviceshall be placed in the test chamber and simulate installed conditions; thetemperature and relative humidity in the chamber shall be + 49 C (+120 F)and 95 percent, respectively. The test conditions shall be maintained for360 hours. At the conclusion of this period, the device shall be returnedto standard conditions. Moisture may be removed by turning the deviceupside down or wiping. Drying by air blast will be permitted. The deviceshall then be operated and inspected within one hour as directed in 3.4. 1.and 3. 4. 2.
4.5. Salt Spray Tests
RIG devices with the connector ends sealed by means of applicable matingplugs, shall be subjected to salt spray per MIL-STD-202, Method 101,Test Condition B. Following exposure, salt deposits shall be removed bya gentle wash in running water, not warmer than 100 F and a light brushing.The samples shall be visually examined for corrosion detrimental to itsintended mechanical function.
4.6. Vibration
This procedure applies to equipment which mounts within 245* cone aroundthe exhaust area of a turbo-jet aircraft engine or on the structure of missilespropelled or launched by high-thrust rocket engines. Although the tests are
SCINTILLA DIVISION ]CHANGE
SIDNEY. N. Y.. U. S. A.
SHEET 9 OF
of comparatively short duration, they are bacd upon the most severeconditions likely to be encountered in missiles, and should be adequatefor most applications, provided that, where possible, consideration isgiven to location so as to avoid extreme environmental conditions. Thespecimen shall be attached, by clamping about its diameter, to a rigidfixture capable of transmitting the vibration conditions specified herein.The amplitude of applied vibration shall be monitored on the test fixturenear the specimen mounting points. Operating requirements and tolerancesshall be as specified below.
4.6. 1. Cycling - The specimen shall be subjected to cycling vibration accordingto the amplitudes and accelerations outlined below. The rate of changeof frequency shall be logarithmic and such that one hour is required toproceed from 20 to 2, 000 back to 20 cps. When there is no provision forlogarithmic cycling, other automatic cycling rates of frequency changemay be used. The cycling test period for each of the 3 mutually perpen-dicular axes shall be two hours, making total test time of six hours.
Frequency (CPS) Sinusoidal Vibration Levels
20 - 87 0. 050 in. D.A.87 - 2000 +20 g
4.7. Shock Test
A shock testing machine designed and fabricated according to JAN-S-44,or equivalent, shall be used to produce the impacts required. The deviceshall be mounted as in the vibration test, 4. 6.
Three resilient impacts shall be applied, in turn, in each direction alongeach of the three orthogonal axes of the specimen, by dropping the carriagefrom a suitable drop height to provide a 50 g peak acceleration. At theconclusion of this test, the device shall be inspected as directed in 3. 4. 1.and 3.4.2.
SCIMTILLA DIVISION 0CHANG
SIDNEY. N. Y., U. S. A. INE XWSPOIAN
SHEET 10 OF
44 j7TE"AEQA-71U2E SEWbO 9 SHALL)SE LOCATMD K"AIDWA..YBF-T EEW F JDo.
Power Dissipated by Device Eln lin - Eout lout
FIGURE 6
4.8. D.C. Temperature Rise
With the RIG device assembled as described in Figure 6, the surfacetemperature of the RIG device shall be recorded for the values below.The device should be tested in such a manner as to preclude any heatsinks or convection currents other than of a negligible nature. Theambient temperature shall be 70 +30 -10 F.
Power Dissipated by RIG Maximum Measured SurfaceWatts Temperature
1.03.05.0
3:8 To maximum wattage11.0 To maximum wattage
*Do not exceed 300 F.
4.9. Terminal Pull Test
A force of 50 pounds shall be applied between the terminals where'theconnections are made. TI.e force is to be applied gradually and heldfor 30 seconds. No relative movement shall be visually observedbetween the parts, nor shall there be any signs of the coupling nutbecoming disengaged from its part.
At the conclusion of this test the device shall be inspected as directedin 3.4.1. and 3.4.2.
CODE 77620
SCINTILLA DIVISION CHANG"
SIDNEY. N. Y.. U. S. A. 7HE guW#' iORPORA10IN
SHEET 11 OF
Figure 7
Equipment for Figure 7.Transmitter; 1. 10 megocycle crystal controlled Millen Model 90, 800 -50 watt
2. 50 megocycle crystal controlled SCR 522 - 15 watt output
3. 100 megocycle crystal controlled SCR 522 - 15 watt output
Detectors: 1. M. C. Jones Model 263 Micromatch . 5-225 mc. toestablish impedance match.
2. Empire model NF 105 Radio Interference Noisemeter
used to detect output level 1 MV sensitivity.
3. Leads and Northrop Model 8657-C Potentiometer.
4.10. A. C. Temperature Rise
4.10. 1. Conditions of Test (A. C.)
Continuous power shall be applied for I hour with the RIG devicein the circut as shown in Figure 7. Power shall be applied until
the temperature sensor reads a surface temperature of 3000 Fmidway between the ends. The ambient temperature shall be 70OF
+'300 -10 0 F. The dev,ce shall be tested in such a manner as topreclude any heat sinks or convection currents other then of anegligible nature.
4. 10.2. Frequency and output detection:
1). C. , 10 mc, 50) ni: and 100 mc continuous power shall be applied
to the RIG device. A suitable detector as shown in figure 7 shallbe used to determine if any measurable output power can be detected.
CODE 77820
SCINTILLA DIVISION 1 CHANGESIDNEY. N. Y.. U. S. A. lIEW 0bq MW
SHEET 12 OF
5. SEQUENCE
5.1. Testing Sequence - All Units
Required Paragraph
I. High Temperature 4. 12. Low Temperature 4.2
3. The rmal Shock 4.34. Vibration 4.65. Shock 4.76. Humidity 4.47. D. C. Temperature Rioe 4.8
8. A.C. Temperature Rise 4. 109. Terminal Pull 4.9
10. Salt Spray 4.5
CTAPPD
Addendum
to
Specification L- 199 10-67
In order to obtain the test data using the test procedures outlinedin the main body of this report, it was necessary to make certainequipment and test diagram changes in specification L-19910-67.These changes do not alter the scope of the test program but doreflect the use of additional equipment. The changes were asfollows:
Paragraph 3. 4. 3. 1 - Figure 2 and the equipment used were asindicated below:
OscillatorOhms mplifier nRL
Load
Oscillator Hewlett Packard Model 650A, or equivalentAmplifier General Radio Power Amplifier Type 1233A, or
equivalent.Voltmeters Fluke True RMS Voltmeter Type 910A, or equivalent
Empire Field Intensity Meter NF-105, or equivalentTransformer Genepal Radio 1632-PI, or equivalentRL .75 --. 02 Ohm Resistive Load-1/Z Watt Non-inductive
Paragraph 3. 4. 3. 2 - Figure 3 and the equipment used were asfollows:
Oscillator XFRBridge R .o7d Oh
D ectector[
A. Equipment for frequencies up to 100 KC
-I-
Oscillator - Hewlett-Packard Model 200 CD, or equivalentImpedance Bridge - General Radio Type 1632A, or equivalentNull Detector - General Radio Type 1232A. or equivalent
Stoddart Field Intensity Meter Model NM-10A,or equivalent
Voltmeter - Ballantine AC Voltmeter Model 643, or equivalentTransformer - General Radio Type 1632-P1,. or equivalentLoad .75 f .02 ohm resistive load, 1/2 watt, non-
inductive
zj. Equipment for frequencies 200 KC to 1 MC
Oscillator - Measurement Signal Generator Model 65B, orequivalent
Impedance Bridge - General Radio Type 916AL, or equivalentNull Detector - Empire Field Intensity Meter Model NF-105,
or equivalent
DC attenuation was measured using the following diagram and testequipment.
in RIGDC
Power R LSource
Iin - Kiethley Electrometer model 610AEin and Eout Fluke Differential DC Voltmeter model 801
Paragraph 4. 10.2 - Figure 7 and the equipment used for the 10and 100 MC RF test were as follows:
H R IG H L O A D
RF Matching DetectorTransmitter Wattmeter Network
Indicator
-2-
lOOMC Transmittcr - SCR 52210MC Transmitter - Millen Model 90, 800 or equivalent
RF Wattmeter - M. C. Jones Model 263 or equivalentDetector - Empire Field Intensity Meter NF-105 or
equivalentTemperature
Indicator - Brown Model 153 x 62P8-X-26 or equivalentLoad - 0.75f. 02 Ohm resistive load - 1/2 watt - non-
inductive
S
-3-
Report Responsibilities
The development activities reported herein have been theresponsibilities of the following persons in the areas indicated.
General - R. R. Mero, Design Engineer, Senior
Analytical - F. E. Hanni, Project Engineer, Research
Testing - Research - D. E. Clark, Project Engineer, Senior
Testing - Environmental - M. A. Champlin, Project Engineer, Senior
I
Bibliography
T.M. No. W-7/62 Series and Parallel Arrangements ofElectrically Initiated Explosives by Wing Commander R.I. Gray
"A Note on the Use of Attenuators in Balanced and UnbalancedNetworks" by Wing Commander R. I. Gray (10 November 1962)
Memo on Attenuation of RIG at DC by Lyde S. Pruett of NWL,dated November 13, 196Z.
Requirements of the Radio-Frequency Interference Guard (RIG)by J. W. L. Lewis
