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Jump to: Connector
Interfaces | Cable Routing | Cable
Assembly Mate/De-Mate Process
Connector
Interfaces:
Interface Cleanliness - Clean Interfaces prolong
connector life and produce more accurate, repeatable
measurements. The use of connector end-caps to protect
test cables and adapters when not in use is recommended.
Interface Cleaning Procedure:
1. Solvents: Connector Insulators, support beads, and seals are susceptible
to solvent damage. Solvents can produce permanent physical and electrical damage.
Isopropyl Alcohol is recommended for cleaning interfaces. It should be noted
that connector interfaces should not be immersed in solvents of any kind because
solvents can become trapped within the connectorized assembly. Trapped fluids
can cause SWR, Phase, and Insertion Loss problems.
2. Applicators: Fibrous or Abrasive applicators can contaminate and even damage
interface surfaces. Clean lint free swabs should be used. They need to be sharp
enough and hard enough to remove dirt and debris without damaging surfaces
and/or dislodging center pins.
3. Method: Dip a clean lint free swab in clean isopropyl alcohol. Press excess
alcohol out of swab on a clean lint free towel. Wipe the interface components
as required to clean the interface. Blow-dry the interface with clean compressed
air. Re-inspect the connector to verify that the interface is clean and ready
for additional inspection procedures and interface gauging prior to use.
Interface Gauging - Incorrect center pin depths
can produce inaccurate measurements and in the case
of protruding center pins can damage test devices,
adapters, and test ports. Frequent interface gauging
can detect gauging problems before they ruin mating
devices (see Table I for connector interface pin depths).
| Table
I: Connector Interface Pin Depths |
| Connector
Interface |
Contact
Location wrt Reference Plane (in) |
Specification |
| 7mm |
-0.002/-0.002 |
IEEE
STD 287 |
| N
Male |
0.210/-0.230 |
MIL-STD-348 |
| N
Female |
+0.187/+0.207 |
MIL-STD-348 |
| 3.5mm |
0/-0.003 |
IEEE
STD 287 |
| 2.92mm |
0/-0.003 |
IEEE
STD 287 |
| 2.4mm |
0/-0.002 |
IEEE
STD 287 |
| 1.85mm |
0/-0.002 |
IEEE
STD 287 |
| SMA |
0/-0.010 |
MIL-STD-348 |
| TNC
/ BNC |
-0.210/-0.230 |
MIL-STD-348 |
| TNC
/ BNC |
+0.186/+0.206 |
MIL-STD-348 |
| 7-16
Male |
+0.0579/+0.0697 |
IEC
169-4 |
| 7-16
Female |
-0.0697/-0.0815 |
IEC
169-4 |
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Recommended Coupling Torque - Incorrect
coupling torque can produce inaccurate measurements
and over-torque coupling can damage test devices,
adapters, and test ports. Torque wrenches should
be utilized to for all Mate/De-Mate processes (see
Table II for recommended coupling torque values).
| Table
II: Recommended Coupling Torque |
| Interface
Type |
Coupling
Torque |
| 7mm,
N |
12
in-lbs |
| 3.5mm,
2.92mm, K®, 2.4mm, 1.85mm |
8
in-lbs |
| SMA,
TNC |
5
in-lbs |
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Cable
Routing:
Bend Radius - Care should be taken to avoid
over-bending test cables beyond minimum bend radius
guidelines. Over-bending can force cable center
conductor off-center, and can force the outer conductor
out of round even to the point of kinking and fracture.
Over bending results in degraded IL and SWR performance.
It should also be noted that coiling cables at
small diameters could force connector center-pins
to protrude beyond required interface dimensions.
Twisting - Twisting test cables should be
avoided at all times. Excessive twist can damage
cable assembly at the cable/connector junction
or even mid-cable depending on how the twist is
applied. Lower level twist can cause measurement
problems as well. Induced stresses on test ports
and device ports can damage the ports. Low level
stresses can cause connections to loosen up.
Cable
Assembly Mate/De-Mate Process:
Interface Alignment - Contact Pins and Dielectrics
can be damaged if misaligned connectors are mated.
Make sure that mating interfaces are parallel and
on center during Mate/De-Mate cycle
Interface Rotation - Plating and surface
finish of outer and inner contacts can be damaged
it connector bodies are allowed to rotate during
Mate/De-Mate cycle. Use wrench flats on connector
bodies to keep them rotationally stationary while
rotating coupling nut during mate/de-mate.
Minimized Load Configuration - Allow test
cable to assume natural bend configuration route
between test port and device port. Loosen test
port connection when test configuration is largely
different than test configuration. Route the cable,
connect device port loosely then tighten both port
connections to recommended coupling torque (see
Table II above). This method will minimize most
bend and twist loading issues.
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