3 IntroductionThe main part of this Standard is based on industrial experience and recommendations from European soldering technology experts. Modifications are incorporated into the text to provide for the specific requirement of low‐outgassing electrical systems which are required by scientific and application satellites. Other additions were made in the light of recent technological advances and results of metallurgical test programmes. The use of processes other than solder assembly is recognized, but only certain general requirements are given in this Standard.These requirements apply to assemblies designed to operate within the temperature limits from ‐45 °C to +85 °C. More extreme temperatures or other unusual environmental applications require special design measures or processing steps to provide environmental survival capability.
4 1 Scopetechnical requirements and quality assurance provisions for assembly and mounting of high-reliability, radio-frequency (RF) coaxial-cable interconnections for use as transmission lines in spacecraft and associated equipment.these assemblies generally designed for low-loss, stableoperation from relatively low frequencies through higherfrequencies in the microwave regionsthese transmission-line cables not to be confused with low- frequency cables with conductive sheaths (usually copper braid), used in applications where shielding of centre conductors from surrounding electrical ambient is requiredInterconnection of those shielded cables is covered in ECSS-Q-ST-70-08
5 Electromagnetic Spectrum Chart sonics10kHz ultrasonics 1MHz microwave cut-off frequency for cable 60GHzcut-off frequency for cable 32GHzlimit for R125 series sma connectors 18GHz
6 Electromagnetic Spectrum BANDWIDTH DESCRIPTION FREQUENCY RANGEExtremely Low Frequency (ELF) to 3 kHzVery Low Frequency (VLF) kHz to 30 kHzRadio Navigation & maritime/aeronautical mobile 9 kHz to 540 kHzLow Frequency (LF) kHz to 300 kHzMedium Frequency (MF) kHz to 3000 kHzAM Radio Broadcast kHz to 1630 kHzTravelers Information Service kHzHigh Frequency (HF) SSB Range MHz to 30 MHzShortwave Broadcast Radio MHz to 26.1 MHzVery High Frequency (VHF) MHz to 300 MHzLow Band: TV Band 1 - Channels MHz to 88 MHzMid Band: FM Radio Broadcast VHF Radio Range MHz to 174 MHzHigh Band: TV Band 2 - Channels MHz to 216 MHzSuper Band (mobile/fixed radio & TV) MHz to 600 MHzUltra-High Frequency (UHF) MHz to 3000 MHzChannels MHz to 806 MHzL-band: MHz to 1500 MHzPersonal Communications Services (PCS) MHz to 1990 MHzUnlicensed PCS Devices MHz to 1930 MHzSuperhigh Frequencies (SHF) (Microwave) GHz to 30.0 GHzC-band MHz to 7025 MHzX-band: GHz to 8.4 GHzKu-band GHz to 14.5 GHzKa-band GHz to 31.0 GHzExtremely High Frequencies (EHF) (Millimeter Wave Signals) GHz to 300 GHzAdditional Fixed Satellite GHz to 275 GHzInfrared Radiation GHz to 810 THzVisible Light THz to 1620 THzUltraviolet Radiation PHz to 30 PHzX-Rays PHz to 30 EHzGamma Rays EHz to 3000 EHz
7 2 Normative references ECSS‐S‐ST‐00‐01 ECSS system — Glossary of terms ECSS‐Q‐ST‐10‐09 Nonconformance controlECSS‐Q‐ST‐20 Quality assuranceECSS‐Q‐ST‐60 EEE componentsECSS‐Q‐ST‐70‐02 Thermal vacuum outgassing test for the screeningof space materialsECSS‐Q‐ST‐70‐08 Manual soldering of high‐reliability electricalconnectionsECSS‐Q‐ST‐70‐26 Crimping of high‐reliability electrical connectionsECSS‐Q‐ST‐70‐28 Repair and modification of printed circuit boardassembliesMIL‐C‐17G(3) SUP1 General specification for cables, radio frequency,flexible and semi‐rigid. (8 Jan 1996)
8 3 Terms, definitions and abbreviated terms 3.1 Terms from other standardsFor the purpose of this Standard, the terms and definitions from ECSS‐S‐ST‐00‐01 apply, in particular for the following term: requirement3.2 Terms specific to the present standard3.2.1 minimum bend radiusinside radius of the bend measured on theouter surface of the cable
9 3 Terms, definitions and abbreviated terms For the purpose of this Standard, theabbreviated terms from ECSS‐S‐ST‐00‐01 andthe following apply:Abbreviation MeaningFEP fluorinated ethylene propylene PTFE polytetrafluoroethyleneSMA sub miniature version AVSWR voltage standing wave ratio
10 4 Principles and prerequisites of reliable soldered or crimped cable connections 4.1 Principles of reliable soldered or crimpedsemi-rigid cable connectionsReliable soldered or crimped connections result from proper design, control of tools, materials and work environments and careful workmanship
11 4 Principles and prerequisites of reliable soldered or crimped cable connections 4.1 Principles of reliable soldered or crimped semi-rigid cable connections (continued)Basic design concepts for reliable connections andwhich prevent joint failure:a. Avoidance of dimensional mismatch between coaxial-cable assembly and units being connected; i.e. not forcing the semi-rigid cable assembly into position and thereby cracking or pre-stressing jointsb. Use of cable-end connectors with retractable (non-captive) coupling nuts; after completion of mounting, the coaxial-cable assembly is not in a state of tension resulting from axial movement when connectors are threaded together
12 4 Principles and prerequisites of reliable soldered or crimped cable connections 4.1 Principles of reliable soldered or crimped semi-rigid cable connections (continued)c. Minimizing internal stresses on soldered or crimped connections resulting from exposure to thermal cyclingNOTE thermal coefficient of expansion of the dielectric isabout 10 times that of copper and in service this can introduce a tensile stress on the jointd. The various assembly and mounting processes are covered by quality-control inspection steps.
13 4 Principles and prerequisites of reliable soldered or crimped cable connections 4.2 Prerequisites for assembly and mounting of semi-rigid coaxial cablesdocumented soldering or crimping programmes:procedures for training, certification, maintenance of certified status recertification and revocation of certified status for soldering, crimping and inspection personnelworkmanship standards consisting of satisfactory work samples or visual aids illustrating quality characteristics for all connections involved, including applicable illustrations in annex B of this Standard
14 4 Principles and prerequisites of reliable soldered or crimped cable connections 4.2 Prerequisites for assembly and mounting of semi-rigid coaxial cablesRecords kept to provide identification between finishedproduct and operator. Records also maintained oftraining, testing and certification status of assemblyoperators. Records retained for at least one year, orlonger if this is specific requirement of the customer’sprojectEquipment and tools verified and calibrated periodicallyfor proper operation, and records of tool calibration andverification maintained (see clause 5.8).
15 4 Principles and prerequisites of reliable soldered or crimped cable connections 4.2 Prerequisites for assembly and mounting of semi-rigid coaxial cables (continued)For soldering or crimping requirements not covered in this Standard, the contractor submits a process procedure including all pertinent quality requirements to customer’s project office for approval in accordance with ECSS-Q-ST-70.
16 4 Principles and prerequisites of reliable soldered or crimped cable connections 4.3 Alternative coaxial cable technologiesAlternative coaxial cable technologies are accepted forapplication in individual customer programmes followingthe completion of qualification and batch acceptancetest programmes in accordance with 5.7. Theprecise test-programme and results are subject toreview and acceptance by the relevant customerprogrammeFor materials used in the alternative technology seeECSS-Q-ST-70-71Some mounting requirements for alternative technologies are given in 5.6.3
17 5 Requirements 5.1 Preparatory conditions 5.1.1 Facility cleanliness a. Unless classified as a cleanroom, areas in which solderingis carried out shall be maintained in neat orderly fashionwith no loose material (dirt, dust, solder particles, oilsand clipped wires) that can cause contamination of thesoldered connection.Furniture kept to minimum in work areas and bearranged to allow easy and thorough cleaning of the floorc. A washroom and eating, drinking and smoking facilities should be located close to, but outside, the soldering areas.
18 5 Requirements 5.1.1 Facility cleanliness (continued) d. Working surfaces covered with an easily cleanedhard top or have a replaceable surface of clean, non-corrosive silicone-free paper.e. Clean tools in the soldering operationf. excess lubricants removed before soldering starts.g. Before assembly, wire, terminal and connector contactsvisually examined for cleanliness, absence of oilfilms and freedom from tarnish or corrosion.
19 5 Requirements 5.1.2 Environmental conditions a. controlled environment that limits entry of contaminationb. room temperature: 22 ± 3 ºCrelative humidity at room temperature 55 ± 10 %c. work stations not be exposed to draughtsfresh air supplied to the room through filtering system; positive pressure with respect to adjacent rooms.
20 5 Requirements5.1.3 Lighting requirementsa. lighting intensity minimum of lux onwork surfaceb. at least 90 % of the work area shall be shadowless and without severe reflections
21 5.1.4 Equipment and tools 5 Requirements 188.8.131.52 Brushes a. The supplier shall use brushes for cleaning, provided that they do not scratch the metal surface to be cleaned or damage adjacent materials beyond their visual inspection requirements.NOTE Medium‐stiff natural‐ or synthetic‐bristle brushes can be used.b. The supplier shall clean these brushes before use in a solvent prescribed in clausec. The supplier shall not use wire brushes.
22 184.108.40.206 Equipment and tools (continued) 5 RequirementsEquipment and tools (continued)5.4.2 Filesa. The supplier shall use smooth, single cut and mill type files for dressing copper soldering‐iron tips and removing burrs from the conductor.b. The supplier shall not use files on surface‐treated tips or pretinned items.NOTE Nickel plated is an example for surface‐treatment.c. The supplier shall keep the files in a good condition and shall be cleaned before use.d. The supplier shall not keep the files in a cleanroom environment.
23 5 Requirements 220.127.116.11 Cutting tools a. Cutting tools for preparation of the semi-rigid cable:Fine-tooth jeweller’s saws (0,28 mm - 0,33 mm blade preferred)razor blades (single edged)suitable wire cutters.b. The jeweller’s saw shall be used together with a cable clampingdevice; see Figure C-1.
24 5 Requirements 18.104.22.168 Cutting tools (continued) c. The supplier shall cut the dielectric and inner conductor with a tool that produces a clean, smooth‐cut surface along the entire cutting edge.d. The supplier shall not perform any twisting action during this cutting operation.
25 5 Requirements 22.214.171.124 Cable-forming tools Bending jigs (Figure C-2) available to form cable to predeterminedshapes as identified by the contractor’s engineering drawingRoller sizes to be available for each cable diameter.Equipment not to introduce dents, nicks, wrinkles or cracksin cable outer conductor.
26 5 Requirements 126.96.36.199 Cable stripping and dressing tools a. The supplier shall use cable stripping and dressing tools in such a way that they do not twist, ring, nick, or score the underlying material surface.NOTE Many pieces of commercially available equipment exist to strip the outer conductor or the dielectric material. These can be automatic, power‐driven devices with precision factory‐set non‐adjustable cutting and stripping dies, or precision hand‐type strippers with accurately machined cutting heads.b. The supplier shall perform either periodic calibration or sample evaluation during a production run.
27 5 Requirements 188.8.131.52 Heat-treatment chamber a. The supplier shall use thermal cycling cabinets, ovens, refrigeration units or cold chambers capable of maintaining temperatures between ‐50 °C and +90 °CNOTE Under certain circumstances (see Table 5‐2 step 3.3) greater temperature extremes can be required.b. The supplier shall calibrate the working zone to within ±5 °C.
28 5 Requirements 184.108.40.206 Soldering equipment a. The supplier shall accomplish one of the following soldering methods that conforms to the requirements on “Equipment and tools” of ECSS‐Q‐ST‐70‐08:1. by hand or2. by using a resistance heating unit or3. other contact heat source ** eg thermal resistance tweezers, solder pot
29 5 Requirements 220.127.116.11 Soldering equipment b. When non‐contact heat sources are utilized, the supplier shall set up, operate and demonstrate to the satisfaction of the customer that the particular method and schedule produces joints of an acceptable standard.NOTE This includes verification testing as detailed inclause 5.7.
30 5 Requirements 18.104.22.168 Crimping equipment a. The supplier shall use the settings recommended by the tool manufacturer as a guide.NOTE This is necessary since manual crimping tools are available; they are custom designed and applicable only for particular connector shells.b. The supplier shall set up the tool for the cable and connector types by a detailed calibration programme based on the requirements of ECSS‐Q‐ST‐70‐26.c. The supplier shall perform verification testing as detailed in clause 5.7.
31 22.214.171.124 Assembly equipment, tools and processes for other technologies 5 RequirementsAssembly equipment, tools and processes for other technologiesa. The supplier shall only use the equipment, tools, and processes for the assembly of the cables and connectors that are designed to avoid damage or degradation of the cables and connectors.NOTE The equipment, tools, and processes can be subject to a manufacturing audit by the customer before application in their programme.
32 126.96.36.199 Defective or uncalibrated equipment or tools 5 RequirementsDefective or uncalibrated equipment or toolsThe supplier shall promptly remove and replacedefective or uncalibrated equipment or toolsfrom the work areas.
33 Equipment and tools Sourcing hints: Specialist RF cable assembly tooling such asRadiall: R SMA Solder kit (~£3107 in 2007)Radiall: R Bending kit, (~£550 in 2007)Radiall Technical support Barry WheelertelAvailability & pricing from:Microtek Components telalso: Richardson Electronics Pte LtdTel: Fax:Kaylene Chong
40 Equipment and tools More sourcing hints: Suhner cable cutting device type 9144.Triton PTH (press to heat) light duty soldering toolAmerican Beauty Tools (Jim Steadie)Pace thermal tweezers (2V, 80-W) (obsolete tool)
41 5.2 Material selection 5.2.1 Solder a. The supplier shall use solder ribbon, wire and preforms, provided that the alloy and flux conform to the requirements on “material selection” of ECSS‐Q‐ST‐70‐08.NOTE 1 The following solder alloys are approved:• 60 Sn (remainder lead): For degolding operations, coating and pretinning.96 Sn (remainder silver): For making coaxial‐cableouter‐conductor‐to connector solder joint.96 Sn or 63 Sn (remainder lead): For contact‐pinsoldering and cover soldering of right angleconnectors.NOTE 2 Refer also to the table of “Chemical composition of spacecraft solders” in ECSS‐Q‐ST‐70‐08.
43 5.2 Material selection 5.2.2 Flux The supplier should perform degolding andpretinning operations with activated fluxes.NOTE Examples of activated fluxes areJ‐STD‐004 Type ROL1 and ROH1.b. The supplier shall completely remove activatedfluxes immediately after use and before anyfurther soldering operation.c. The supplier shall only use pure rosin fluxfor spacecraft assembly work.NOTE An example of pure rosin flux isJ‐STD‐004 Type ROL0.
44 Solder theory: Intermetallics Cu3Sn Cu6Sn5Au AuSn AuSn2Data source: September 2001 presentation by Istituto Italiano della Saldatura (LM)
47 (Eutectic means lowest melting point, no melting range) Eutectic Sn/Pb(Eutectic means lowest melting point, no melting range)183°CSolidLiquidSn63/Pb37 is near eutectic and recommended for pcb solderingFor solder-pot processes, the amount of Sn in excess of 61.9% allows for Sn depletion during use.Sn61.9/Pb38.1 is true eutectic
55 No Thermal (solder) Bridge RFCableSOLDERINGIRONConnector bodySLOW HEAT TRANSFERLONGER DWELL TIME
56 Thermal (solder) Bridge FASTER HEAT TRANSFERRFCableConnector body
57 5.2 Material selection 5.2.3 Solvents The supplier shall only use solvents for the removal of grease, oil,dirt, flux and flux residues that are non-conductive and non-corrosive.dirt, flux and flux residues that do not dissolve or degrade the qualityof parts or materials or remove their identification markings.The supplier shall label the solvents and maintain them in a clean anduncontaminated condition.The supplier shall not use solvents showing evidence of contaminationor decomposition.e. The supplier shall not use solvents that transfer dissolved fluxresidue onto contact surfaces.NOTE This can be the case for switches, potentiometers orconnectors.f. The supplier shall use solvents in conformance withECSS‐Q‐ST‐70‐08, clause 6.4h.
58 5.2 Material selection 5.2.3 Solvents (continued) Extract from ECSS-Q-ST-70-08, clause 6.4h:
59 5.2 Material selection 5.2.4 Cable selection The supplier shall procure semi‐rigid cables inconformance with the detailed requirements ofMIL‐C‐17G(3) SUP1.NOTE The selection of a particular coaxial cableInvolves consideration of the specific electrical,mechanical and environmental requirements of theproject.
60 5.2 Material selection 5.2.4 Cable selection (continued) b. The supplier shall procure semi‐rigid cable with outerconductor diameter standardized as either0,085 inches or 0,141 inches (±0,001 inches) andfabricated from copper.NOTE The outer conductor can be finished withsilver plating.RG ”RG ”0,141 ” semi rigid cable: MIL M17 / 130-RG4020,085” semi rigid cable: MIL M17 / 133-RG405
62 5.2 Material selection 5.2.4 Cable selection (continued) c. The supplier shall procure semi‐rigid cable withdielectric material composed ofpolytetrafluoroethylene (PTFE) or fluorinatedethylene propylene (FEP).d. The supplier shall select the material compositionof the inner conductor following a review of thespecific project/equipment requirements.NOTE 1 The review also considers the proposedconnector designs.NOTE 2 In general copper is a suitable innerconductor.6262
64 5.2 Material selection 5.2.5 Connector selection The supplier shall only select approved connectors in conformancewith the requirements on “Quality levels” of ECSS-Q-ST-60, foruse in assembling solder-type semi-rigid cables.b. The supplier may use connectors with the form of:straight cable-end connector, with a centre contact, and non-captive coupling nut;NOTE See Figure C-3 for distinction between non-captive and captivecoupling nut connectors.2. right angle cable-end connector.3. flange‐mount male receptacle, either two- or four-hole type.c. The use of right angle cable-end connector shall be restricted toapplications where stress-free mounting of cables with thesecaptive nut connectors can be assured.d. For other applications the use of right angle cable-end connectorshould be minimized.6464
66 5.2 Material selection 5.2.5 Connector selection (continued) e. All non‐metallic materials incorporated in the connectorshall meet the outgassing requirements according toECSS‐Q‐ST‐70‐02.f. The supplier shall not use pure tin or cadmium finishes.g. For the use of special connectors for non‐soldersystems, the supplier shall obtain customer approval.6666
67 5.2 Material selection 5.2.5 Connector selection (continued) Supplementary notes concerning Radiall connectors:R124XXX XXX: Commercial for DC – 6GHzR125XXX XXX: Standard for DC – 18GHz(other options to 27GHz)R126XXX XXX: Space Qualified; similar performanceto Standard but with beryllium-copper body and centrecontact6767
68 5.2 Material selection 5.2.5 Connector selection (continued) Link to Radiall search result (example r ):Link to Radiall Product datasheet & Assembly instructions:6868
69 Connector data (from http://www.wa1mba.org/rfconn.htm) Return Loss of Johnson Components Field Replaceable SMA connector.Mounted on a chassis, not a cable. Return loss bumps at 12.4, 18, and26.5 GHz are indications of SMA geometric constraints that have led tothose specific frequency limitations in some SMA connectors.6969
70 Connector data (from http://www.wa1mba.org/rfconn.htm) 703.5 mm and SMA mating SWR70
71 Connector data (from http://www.vitelec.co.uk/) Plating very important at microwave frequencies because of skin effect. At very high frequencies, signals do not penetrate far into the conductors, power and current flow in metals is essentially on the surface, or “skin”, of the conductors.We take advantage of this by plating a fairly good conductor with several skin depths of an excellent conductor.Thus, the electrical properties of the excellent conductor are obtained with minimum cost. Skin effect pronounced at high frequencies and usually not a concern below a few GHz.The following table shows relative properties of severalcommon connector platings and base metals.Electrical conductivity shown is relative to brass. eg Silver is 2.4x better while Stainless Steel is 20x worse than brass.7171
72 Other causes of high VSWR and Insertion Loss air gappoor solder fill (<70%) beween contact and centre conductorInsertion loss:crushed cablebend radius too tight7272
73 Connector data (from http://www.vitelec.co.uk/) 7373
74 Connector data(fromMIL-DTL Radio Frequency Connectors APPLICATION NOTES1) Plug coupling nuts and cable nut mounted connectors may have silicone rubberO-Ring seals which are an outgassing concern. Connectors may require additionalprocessing for outgassing control. This should include a bake of the connector andremoval or replacement of the silicone rubber O-Rings with fluorosilicone O-Ringswhich meet outgassing requirements.2) Temperature range for flexible and semirigid connectors is -65°C to +165°C. Temperature range for PC mounted connectors is -65°C to +105°C.3) The use of safety wire is recommended to secure mated connectors together.4) B designated connectors which require special tooling for assembly are considerednon-field replaceable and are not preferred. Most are inactive for new design.5) Only series SMA connectors are recommended for satellite use in lower earthorbits. Series N and TNC connectors are not recommended for use in lower earthorbits due to atomic oxygen corrosion concerns of their silver plating.7474
75 Radiall products http://www.radiall.com/main.php • ESA Qualified Part List ( QPL ):More than 400 part numbers under : • ESA SCC 3402/001• ESA SCC 3402/002• ESA/SCC 3402/003• SMA connectors under : • ESA SCC 3402• RADIALL RAD C 2612• Customer requirements75
77 5.2 Material Selection 5.2.5 Connector selection (continued) Supplementary notes concerning degolding:fine solder braid (for degolding inside connector body)and22AWG (19 x 0.15) stranded wire(for degolding inside centre contact)7777
78 5.3 Preparation of semi-rigid cable 5.3.1 Generalcoaxial cables shall be supplied in the form ofstraight lengthsNOTE initial preparation is similar for each cablediameter and each connector type, whetherjoining by soldering or crimping7878
79 5.3 Preparation of semi-rigid cable 5.3.2 Inspection of cabledelivered cable shall be removed fromcontainer and inspected for dents,nicks, wrinkles, blisters andcontaminationb) above are cause for rejection7979
80 5.3 Preparation of semi-rigid cable 5.3.3 Cutting cable to initial oversize lengthtotal required length of the cable calculated fromengineering drawing taking account of bends andanglesb) additional length of approximately 10 mmis added to allow for bending, preconditioning andend dressing.c) cable held in special fixture, eg Figure 1, and cutto “initial length” using fine-toothed jeweller’s sawd) don’t overtighten the special fixture, as this candamage the cablee) cut end shall be deburred and examined.8080
81 5.3 Preparation of semi-rigid cable 5.3.4 Cable forming and minimum bend radiusa) cables shall be formed to required shapedimensions before cable preconditioningNOTE suitable jig (see Figure C2) shall be providedb) only one bending operation shall be performedto form each shapec) no attempt shall be made to reshape a bent cable8181
82 5.3 Preparation of semi-rigid cable 5.3.4 Cable forming and minimum bend radius (continued)d) design rules shall establish minimum bend radii as inTable 5-1inside radius of bend measured on outer surfaceof cableTable 5-1: Design rules for minimum bend radius8282
83 5.3 Preparation of semi-rigid cable 5.3.4 Cable forming and minimum bend radius (continued)e) Each finished cable end shall have a minimum straight length ofcable to allow for clearance during the assembly and mountingoperationsf) The straight length shall be greater than 10 mm for 0,085diameter cableg) The straight length shall be greater than 20 mm for 0,141h) Prevent wrinkling or crackingi) Bending of the cable shall be by applying slow, even, continuouspressure8383
84 5.3 Preparation of semi-rigid cable 5.3.5 Preconditioning heat treatmentGeneralThe supplier shall achieve core stress relief bypreconditioning each cable before it becomesa cable assembly.8484
85 5.3 Preparation of semi-rigid cable NOTE The electrical and mechanical performancesspecified for semi‐rigid cables are achieved by acompression fit between the outer conductor andthe dielectric core, which, in turn, necessitatesmanufacturing processes that cause deformation ofthe core by compression and elongation.The resulting stress that is initially non‐uniform tendsto equalize by cold flow within a few weeks after themanufacturing and causes withdrawal of the core intothe cable. If this occurs in cable that has become partof a cable assembly, the resulting development of anair‐gap at the cable/connector interface causes anincrease in the voltage standing wave ratio (VSWR).Therefore the preconditioning is performed.8585
86 5.3 Preparation of semi-rigid cable 5.3.5 Preconditioning heat treatment (continued)Heat treatment processThe supplier shall perform preconditioning in conformance with Table 5-2on cables that are formed into the required bend configuration.b. The supplier shall not perform preconditioning on a soldered or crimped cable.NOTE This is valid even if only one lead end is terminated to a connector.c. The supplier shall place the entire cable in the thermal cyclingarrangement.d. The rate of change of temperature shall not exceed 2 °C perminute.NOTE Recommendations for dealing with special requirements (e.g.higher operating temperature extremes) can be obtained fromcable manufacturers.8686
87 Thermal Coefficient of Expansion (CTE) Typical CTE Values in Electronics:glass or ceramic => ppm/°CFR4 x-y axis => ppm/°CFR4 z axis => 180ppm/°CPolyimide-glass x-y axis => ppm/°CPolyimide-glass z axis => ppm/°CCopper => ppm/°CAluminium => ppm/°CSolder (Sn60) => ppm/°CDielectric, polytetrafluoroethylene (PTFE) or fluorinated ethylene propylene (FEP)=> approx 160 ppm/degCNeed for Stress Relief to accommodate differential expansionacross 135deg DT (full sun to earth shadow)Or…. 300deg DT (room temp to soldering temp)87
88 Table 5-2: Preconditioning heat treatment process 8888
89 Thermal Cycling (Preconditioning) Requirements Ramp rate not to exceed 2ºC/minuteDwell times = 1 hourTemperature range ºCMinimum 3 complete cycles89
90 Thermal Cycling (Preconditioning) Requirements Thermal Cycling (Preconditioning) RequirementsStepPreconditioning ActionTime ( h )12345678Cool from +25°C to –45°C *-45°C for 1 hourReturn to ambient (+25°C)ambient for 1 ourHeat from +25°C to +85°C *+85°CReturn to ambient *ambient for 1 hourMeasure dielectric protrusion / trim flush* max rate of change = 2°C/min0:351:000:30Single cycle duration:6:102nd cycle, as above3rd cycle, as above6.10Stabilising soak of (24-1) hours23:00Minimum Total duration:41:3090
91 5.3 Preparation of semi-rigid cable 5.3.6 Trimming cable to final lengthAfter the preconditioning, the supplier shall adjustthe cable form to the tolerance of the engineeringdrawing.b. The supplier shall cut the cable to size such thatwhen it is assembled it fits with minimum stress.c. The supplier shall perform cutting in conformancewith the directions given in clause9191
92 5.3 Preparation of semi-rigid cable 5.3.7 Stripping the cable endsThe supplier shall use milling tools for stripping thecable ends.NOTE See also clauseb. For each stripping operation, the supplier shall followwritten instructions.NOTE This allows a reproducible process that doesnot damage the conductor surfaces.c. The supplier shall regularly change cutting and millingblades.d. The supplier shall remove burrs.9292
93 Removing Outer SheathUsing Radiall tools, fit cable into trimming tool & collett, items 55 & 58.Trim with jeweller’s saw, 0.33mm blade to achieve 3.17 ± .005mm trim length.Carefully trim dielectric with a single-edged razor blade.The outer sheath and dielectric should now be removed using a rotating motionas shown in the drawing below.93
94 5.3 Preparation of semi-rigid cable 5.3.8 Inspection of stripped cable endsFor each of the stripped ends, the supplier shallperform a quality control inspection checking thefollowing criteria:no metal or foreign particles are on the face ofthe dielectric.2. the outer conductor contains no burrs or majorsurface defects and is flush with the dielectric.3. unremoved dielectric near the centre conductordoes not exceed 0,2 mm.9494
95 5.3 Preparation of semi-rigid cable 5.3.8 Inspection of stripped cable endsb. The supplier shall specify the length of the wire innerconductor.NOTE This is necessary since the length is dependent onthe connector type.c. The supplier shall report measurements of the externallength of the centre conductor as shown in Figure 5‐1in the logbook for cable prior to assembly with SMAconnectors having separate pin contacts.9595
97 5.4 Preparation for soldering assembly of semi-rigid cables 5.4.1 GeneralThe supplier shall establish written procedureswhich define the various process stepsincluding as a minimum the requirements ofclause and9797
98 5.4 Preparation for soldering assembly of semi-rigid cables 5.4.2 Degolding and pretinningThe supplier shall remove gold from all surface areas tobe joined by soldering.NOTE The central contact pin can be degolded andpretinned with a soldering iron by melting a short lengthof 63 Sn or 60 Sn solder wire within the cup to dissolvegold plating; the liquid solder can then be wicked‐out withstranded wire.9898
99 5.4 Preparation for soldering assembly of semi-rigid cables 5.4.2 Degolding and pretinning (continued)b. The supplier shall degold and pretin the jointing surfaceof the connector body by fitting the connector to asuitable sized PTFE plug held vertically in a vice.Fit barrel onto degolding jig, then carefully apply solder to the innerfaces of the barrel, keeping the outer surfaces free of solder.Once fully coated with solder, remove all solder using solder braid and carefully clean.Straight connectors with captive nuts will not seat onto the tool base; therefore,remove insulator from the tool and fully insert it into the connector;otherwise, the insulator will not protect the full depth of the mating side of theconnector body.9999
100 5.4 Preparation for soldering assembly of semi-rigid cables 5.4.2 Degolding and pretinning (continued)c. The supplier may melt solder wire onto thejointing area and remove it with the aid of asolder wick at least twice until the solidifiedpretinned surface has a shiny appearanceindicating a gold‐free condition.100100
101 5.4 Preparation for soldering assembly of semi-rigid cables 5.4.2 Degolding and pretinning (continued)d. With the right‐angle type of connector, the supplier shalldegold and pretin the solder mounting surfaces of theinspection and assembly cover and the correspondingsurfaces of the body before assembly.e. The supplier shall pretin the cable’s outer and innerconductors.f. The supplier shall check for possible dielectric protrusionafter the cable has cooled down to room temperature.101101
102 5.4 Preparation for soldering assembly of semi-rigid cables 5.4.2 Degolding and pretinning (continued)g. The supplier shall trim any protrusion with a scalpelblade.h. The supplier shall check the fit of the pretinned cablein the connector.The supplier may use activated fluxes for degolding andpretinning operations.j. If activated fluxes are used, the supplier shall removethem immediately after the cable has returned to roomtemperature.k. There shall be no dewetting of the solder on the cableconductor or on the connector.102102
103 5.4 Preparation for soldering assembly of semi-rigid cables 5.4.2 Degolding and pretinning (continued)l. The supplier shall clean all surfaces with an approvedsolvent until they are free from all residual flux andother visible contamination.NOTE 1 For solvents refer to clauseNOTE 2 The recommended degolding and pretinningtemperatures are 250 °C to 280 °C, and 210 °C to260 °C, respectively, when using solder immersion.m. The supplier should perform pretinning just beforeproceeding with the assembly of the connector on thecable.103103
104 5.4 Preparation for soldering assembly of semi-rigid cables 5.4.3 Solder preformsa. The supplier shall eitheruse solder preforms with an internal diameter matchingthe outer diameter of the coaxial cable which areavailable as prefluxed continuous rings, orprepare solder preforms by winding 96 Sn solderwire around mandrels having the same outer diameteras the coaxial cable (0,085 or 0,141 inches).104104
105 5.4 Preparation for soldering assembly of semi-rigid cables 5.4.3 Solder preforms (continued)No need to cut into separate rings; better to keep continuous spiral105105
106 5.4 Preparation for soldering assembly of semi-rigid cables 5.4.3 Solder preforms (continued)b. The supplier shall predetermine the diameter of the wire and the numberof turns by trials.NOTE This is necessary since they depend on the type of connector.c. The supplier shall make as many preforms as the number of connectorsto be soldered.d. The supplier shall use a scalpel blade to cut solder turns in a directionperpendicular to the wire wrap.NOTE This is shown in Figure C‐4.e. Before use, the supplier shall clean the preforms with one of the solventcleaners specified in clause 5.2.3106106
107 5.5 Assembly of connectors to RF coaxial cables 5.5.1 Solder assembly of semi-rigid cablesStraight cable-end connectorStraight cable-end connector with non-captive nuteg Radiall type M09Nut Contact Body Insulator107107
108 5.5 Assembly of connectors to RF coaxial cables 5.5.1 Solder assembly of semi-rigid cables (cont’d)Straight cable-end connectorCentre contact assemblyThe centre contact shall be slid onto the prepared centre conductorof the cable with an easy sliding fitThe centre conductor shall be visible across the full diameter ofthe inspection holeThe gap between the rear/end of the centre contact and the faceof the dielectric/outer conductor shall be as specified in theassembly instructions for the type of cable-end connector beingused (eg )NOTE An example is given in Figure C‐5.108108
109 5.5 Assembly of connectors to RF coaxial cables Straight cable-end connector Straight cable-end connectorCentre contact assembly (continued)109109
110 Fitting and soldering centre contact Using Radiall tools, items 10, 15 & 62, assemble centre pinonto centre conductor, spaced away from dielectric with item 62.(Note, Radiall call for item 61 in error!)Carefully feed Sn63 or Sn96 solder into witness hole until filled;limited spillage is acceptable if it does not reach contact area or affect fitof insulator110
111 5.5 Assembly of connectors to RF coaxial cables 5.5.1 Solder assembly of semi-rigid cablesStraight cable-end connectorCentre contact assembly (continued)d. The supplier shall solder the centre contact to the centre conductor with the solder specified in clause and the equipment specified in clausee. After the solder has solidified and cooled, the supplier shall clean the joint with one of the solvent cleaners specified in clausef. After soldering, the supplier shall recheck the gap between the centre contact and the face of the dielectric/outer conductor.111111
112 5.5 Assembly of connectors to RF coaxial cables 5.5.1 Solder assembly of semi-rigid cablesStraight cable-end connectorCentre contact assembly (continued)g. The supplier shall inspect the solder connection against the following criteria:1. The inspection hole is filled with solder.2. The appearance of the solder joint satisfies the “Acceptance criteria” given in ECSS‐Q‐ST‐70‐08.3. There is no flux or other residues on the cable or the contact.4. There is no solder spillage or flow onto the mating surfaces of the contact.5. Where any solder flow or spillage has occurred on the non‐mating outer surfaces of the contact, it does not cause the effective contact dimensions to exceed those specified for successful connector assembly.112112
113 5.5 Assembly of connectors to RF coaxial cables 5.5.1 Solder assembly of semi-rigid cablesStraight cable-end connectorConnector-body/cable assemblya. The supplier shall assemble the remaining connector parts to the cable in the following sequence:Slide any cable identification and other sleeves onto the cable in the sequence defined by the cable assembly or layout drawings or specifications.2. In the case of a straight cable‐end connector, slide the coupling nut onto the cable with the internal thread facing the end of the cable to which the connector is being assembled.3. Slide the solder pre‐form (if used) onto the cable.4. Assemble the body of the connector to the centre contact and the end of the cable.113113
114 5.5 Assembly of connectors to RF coaxial cables Straight cable-end connectorConnector-body/cable assembly (continued)b. The assembly of the body of the connector to the centre contact and the end of the cable should be with an easy sliding fit in both cases (centre contact and pretinned outer conductor fitting).c. At this stage, the supplier shall check the dimensional relationships of the connector body to the centre conductor and the correct full insertion of the cable outer conductor into the connector body.d. The supplier shall solder the outer conductor of the cable to the body of the connector with the solder specified in clause and the equipment specified in clausee. After the solder has solidified and cooled, the supplier shall clean the joint with one of the solvent cleaners specified in clause114114
115 5.5 Assembly of connectors to RF coaxial cables Straight cable-end connectorConnector-body/cable assembly (continued)Eg: Triton PTH (press to heat)light duty soldering tool115115
116 Soldering Outer Conductor to Connector Body Assemble cable & connector barrel onto positioner item 87 and secure with connector nut.Fit into item 10 with 6 turns of solder and a small amount of liquid flux.Apply thermal resistance tweezers across connector barrel,applying a downwards pressure to maintain position during soldering.116
117 surplus dielectric or copper. Dielectric trimmingAssemble cable into trimmer-locator item 93 and secure using connector nut.Carefully enter dielectric trimmer item 95 into locator and rotate to remove anysurplus dielectric or copper.Clean with a dry brush to remove any loose PTFE or copper and examine trimmed faceunder microscope.117
118 Remove from tools and examine for acceptable location of insulator. Fitting InsulatorAssemble finished cable into dielectric insert tool item 34, securing with connector nut.Insert insulator into tool and press into connector with the dielectric plunger item 35.Remove from tools and examine for acceptable location of insulator.118
119 5.5 Assembly of connectors to RF coaxial cables Straight cable-end connectorInspection of assemblya. After soldering and cleaning, the supplier shall inspect the assembly of the connector to the cable against the following criteria:1. The dimensional relationship of the centre contact and body of the connector is correct.2. The appearance of the outer conductor to connector body solder joint satisfies the visual “Acceptance criteria” given in ECSS‐Q‐ST‐70‐08.3. There is no solder flow or other residues on the cable or connector.119119
120 5.5 Assembly of connectors to RF coaxial cables Straight cable-end connectorInspection of assembly (cont’d)4. There is no solder flow or spillage onto the mating surfaces of the connector or onto the shoulder of the connector body where it interfaces with the coupling nut.5. Any other solder flow or spillage onto the body of the connector does not affect the operation of the coupling nut.6. There is no solder spillage or other contamination on the coupling nut.120120
121 Dielectric expansion problem shows problem caused by expanding dielectric duringsoldering process.If this happens a poor VSWR will result.Ways of avoiding this:rapid heat-up (>80W resistance tweezers)minimise heat losskeep parts pressed together during soldering121
124 Solder fillet failure High VSWR: air gap poor solder fill (<70%) between contact and centre conductorInsertion loss:crushed cablebend radius too tight124
125 5.5 Assembly of connectors to RF coaxial cables Right angle cable-end connectora. The supplier shall assemble the connector to the cable‐end in conformance with the requirements b to r.b. After preconditioning as defined in clause 5.3.5, the supplier shall cut the cable‐end to the dimensions necessary for correct fitting to the connector as shown in Figure 5‐2.c. The supplier shall then degold and pretin the cable‐end as defined in clause125125
126 5.5 Assembly of connectors to RF coaxial cables Right angle cable-end connector (cont’d)d. The supplier shall prepare the connector by degolding the bifurcated pin, the seating for the cover and the cover.e. The supplier shall insert the cable into the connector and the assembly (cable and connector) and shall ensure that the angular relationship between preformed cable and connector is correct.f. The supplier shall inspect the insertion of the cable into the connector via the inspection/assembly hole to ensure that it is in conformance with Figure 5‐2.g. The supplier shall make first the solder joint between the inner conductor of the cable and the bifurcated pin of the connector with the aid of a fine soldering iron and the solder defined in clause126126
127 5.5 Assembly of connectors to RF coaxial cables Right angle cable-end connector (cont’d)h. After the solder has solidified and cooled, the supplier shall clean the centre‐conductor solder joint and the cavity in the connector body with one of the solvent cleaners specified in clausei. The supplier shall inspect the solder joint to ensure that full insertion of the inner conductor of the cable into the bifurcated pin of the centre conductor of the connector has taken place.NOTE See also Figure 5‐2.j. The supplier shall inspect the solder joint to ensure that the “Final inspection” requirements of ECSS‐Q‐ST‐70‐08 are satisfied.k. The supplier shall now solder the outer conductor of the cable to the body of the connector with the aid of the solder specified in clause and the equipment specified in clausel. After the solder has solidified and cooled, the supplier shall clean the joint with one of the solvent cleaners specified in clause127127
128 5.5 Assembly of connectors to RF coaxial cables Right angle cable-end connector (cont’d)m. The supplier shall inspect the solder joints between the cable and the connector to ensure that the dimensions of the cable‐connector interface still conform to Figure 5‐2n. The supplier shall inspect the solder joints between the cable and the connector to ensure that the solder joints conform to the “Final inspection” requirements of ECSS‐Q‐ST‐70‐08.o. The supplier shall now assemble the cover to the inspection/assembly hole and the solder joint formed with a soldering iron using the solder specified in clausep. The supplier shall not add extra solder during this operation.NOTE 1 The joint relies on reflowing of the solder applied during the degolding/pretinning operation only.NOTE 2 This is to prevent the flow of excess solder into the cavity in the connector body.128128
129 5.5 Assembly of connectors to RF coaxial cables Right angle cable-end connector (cont’d)q. After the solder has solidified and cooled, the supplier shall clean the joint with one of the solvent cleaners specified in clauser. The supplier shall inspect the cover solder joint with respect to the following criteria:1. The solder joint extends around the complete periphery of the cover.2. The cover is fully inserted into the shoulder of the holeNOTE See Figure 5‐2.3. The solder joint conforms to the “Final inspection” requirements of ECSS‐Q‐ST‐70‐08.129129
130 Figure 5-2: Right angle cable-end connector assembly 130
131 Right-angled connector assembly This shows the Radiall right-angled connector.Degolding is required on all soldered surfaces:bifurcated area of centre pinJoint area where body meets outer sheathcover and cover seating areaWhen soldering the centre conductor to the bifurcated pin,achieve a good solder fillet in the slot.131
132 5.5 Assembly of connectors to RF coaxial cables 5.5.2 Crimp assembly of semi-rigid cables and other assembly techniquesa. The supplier shall assemble the connectors and cables in conformance with formally documented and qualified procedures.b. The supplier shall submit these procedures for customer acceptance.NOTE This acceptance can involve a customer audit of the facilities and procedures used for assembling the cables and connectors.c. As final stage of assembly, the supplier shall perform an inspection covering dimensional conformance, cleanliness, lack of damage and quality of the assembly techniques used.132132
133 Crimped RF Cable Connector Here is one version of a crimped RF connector.A serrated ferrule is positioned at the entrance of the tapered barrel.The crimp tool forces this ferrule into the taper where it forms acompressive fit.Often, this type of connector uses no centre contact; instead, thecopper-clad iron centre conductor is profiled to the required shape.133
134 Soldering & trimming outer conductor (eg for connector not having separate contact pin)134
135 Forming Centre Contact Profile (eg for Radiall type M07 connector not having separate contact pin)Using item 90 from the Radiall kit,the protruding centre conductor is filed to theangle of the face block while rotating the cable.Considerations:not a gold-plated contact surfacemore liable to misalignment with the tines in the socketperformance advantage since no impedance changes due to separatecontactbest used in applications which do not require frequent mating cyclespointed conductor may tend to remove plating and base metal in matingfemale conductor if the connectors are subject to many mating cycles135
136 5.5 Assembly of connectors to RF coaxial cables 5.5.3 Completed assembliesa. When the assembly of the cable and connectors is complete, the supplier shall inspect it to ensure that it is dimensionally correct and clean.NOTE 1 “Dimensionally correct” means in accordance with the layout drawing or jig.NOTE 2 “Clean” means for example free from contaminants, particles and burrs.b. The completed and inspected cable assembly shall have protective caps fitted over the connectors.136136
137 5.5 Assembly of connectors to RF coaxial cables 5.5.3 Completed assemblies (cont’d)c. Where for thermal or other reasons the cable assembly is painted, the paint shall be applied to the outer conductor of the cable only and shall stop at least 5 mm before the joint to the connector (e.g. solder fillet and crimp ferrule).NOTE Connectors are not painted.137137
138 5.5 Assembly of connectors to RF coaxial cables 5.5.3 Completed assemblies (cont’d)d. The paint used shall conform to the “Acceptance limits” requirements of ECSS‐Q‐ST‐70‐02.e. The supplier shall store the cable in a suitable container inside a sealed bag with an inert atmosphere.f. The storage packaging shall be adequate to protect the cable against deformation, damage and contamination.g. The supplier shall provide a suitable shipping container to give the necessary additional protection to the storage packaging for delivery purposes.138138
139 5.6 Mounting of cables (cont’d) 5.6.1 Semi-rigid cables with straight solder-type connectorsa. The supplier shall remove the assembled cable from its storage packaging only when it is needed for immediate mounting.b. After removal from the storage packaging, the supplier shall inspect the cable assembly before mounting.c. The supplier shall ensure that the mating surfaces and screw threads are clean and free from damage.d. The supplier shall retract the connector coupling nuts along the cable until they are at least 1 cm clear of the connector body.139139
140 5.6 Mounting of cables (cont’d) 5.6.1 Semi-rigid cables with straight solder-type connectors (cont’d)e. The connector inner contacts shall be inserted into the receptacles in the mating halves and slid home so that the mating faces of the bodies of the mating connectors are in contact.f. During this operation, the supplier shall apply no lateral force to correct misalignment of the cable‐end connectors and the mating connectors.g. Longitudinal force shall only be applied in the case where the connectors mating with the cable are facing each other140140
141 5.6 Mounting of cables (cont’d) 5.6.1 Semi-rigid cables with straight solder-type connectors (cont’d)h. In the case specified in 5.6.1g, the following shall apply:1. limit the force to that required to compress the cable temporarily by the length of one connector inner contact mating face.2. ensure that the cable has generous stress relief bendsNOTE This allows the temporary compression to be, in fact, a minor bending.i. At the completion of the connector mating operation, the cable shall be lying without external force, both cable‐end connectors having the inner contacts fully inserted and the cable lying in contact with all support points.141141
142 5.6 Mounting of cables (cont’d) 5.6.1 Semi-rigid cables with straight solder-type connectors (cont’d)j. The supplier shall now loosely screw the two connector coupling nuts onto the mating connector bodies and tighten to the specified torque, but in the range 0,8 Nm to 1,1 Nm.k. During the nut mating and torquing operations, the supplier shall ensure that no rotation of the cable‐end connector body or of the cable takes place.l. The supplier shall now secure the cable to its support points (where applicable).m. The supplier shall reject any cable that cannot be installed in conformance with the procedure described in the requirements 5.6.1a to 5.6.1l and shall provide a new cable to the correct dimensions.142142
143 5.6 Mounting of cables (cont’d) 5.6.2 Semi-rigid cables with right-angle connectorsa. The supplier shall unpack and inspect the cable as defined in requirements 5.6.1a to 5.6.1c..b. The supplier shall align the cable‐end connectors with their mating connectors simultaneously and the centre contacts with their mating receptacles.c. During this operation, the supplier shall apply no lateral force to correct misalignment of the cable‐end connectors and the mating connectors.143143
144 5.6 Mounting of cables (cont’d) 5.6.2 Semi-rigid cables with right-angle connectors (cont’d)d. The supplier shall screw the connector coupling nuts onto the mating connector bodies until finger‐tight and shall then unscrew it 1/4 turn.NOTE In this condition the cable is resting in contact with its support points (where applicable), but is free to move within the constraint given by the 1/4 turn loosening of the connectors.e. The supplier shall now finger‐tighten and torque the connectors to the specified figure for the particular connector, but in the range 0,8 Nm to 1,1 Nm).f. During the nut mating and torquing operations, the supplier shall ensure that no rotation of the cable‐end connector body or of the cable takes place.144144
145 5.6 Mounting of cables (cont’d) 5.6.3 Other cable mounting technologiesa. The mounting requirements for other technologies should be defined by the suppliers of the connectors, cables or assemblies.b. The supplier shall use everywhere stress‐free mounting of assembled cables to the interfacing connectors .c. For each technology, the supplier shall respect the bend‐radius constraints for the particular type of cable.d. The supplier shall respect the cable‐support requirements for the particular type of cable.145145
146 5.6 Mounting of cables (cont’d) 5.6.3 Other cable mounting technologies (cont’d)e. Particularly in the case of flexible cables having an expanded type of dielectric, the cable clamps should be of a carefully designed rigid type that enables any forces resulting from vibration to be distributed over a significant length of the cable.NOTE 2 This is done to avoid local dielectric crushing and, hence, degradation of electrical performance.146146
147 Process Verification 5.7.1 General a. The supplier shall conduct verification tests to establish confidence in the reliability of solder-joint configurations and processing methods not shown in this Standard.b. The configuration shall be considered verified if no cracked solder joints or part damage is found after 200 thermal cycles in accordance with the test conditions given in clause and vibration given in clause and when the configuration is examined under 15× minimum magnification.c. The supplier shall ascertain the absence of cracks within the interconnection by metallography, microsections being made in the longitudinal mid-plane of the assembly.147147