P1dB Cable Assembly Methodology for Measuring Length
There are various methods for measuring the length of an RF coaxial cable assembly, and they will vary between assembly houses.
That is why it is good practice to understand the techniques used at the chosen
assembly house to measure an RF cable jumper, otherwise the received cable may
not satisfy a design requirement. In order to ensure that the correct cable is
built to your specific requirement, P1dB has identified its measurement guide
used at our factory.
Straight Connectors
Straight connectors are all measured at the reference plane of the connector. This rule applies to Standard, Reverse Polarity and Reverse Thread connectors. This measurement technique also applies for non-bulkhead and non-panel-mount connectors.
Panel Mount and Bulkhead Connectors
The exceptions to the reference-plane rule are bulkhead and panel mount connectors. This is because the length that is important for designs is from a panel to the other connector. Using the reference-plane rule for panel-mount and bulkhead connectors would complicate building cable assemblies, since the distance from a connector reference plane to a panel varies, even within the same series.
Right Angle Connectors
Right angle connectors are measured from the center contact, since the reference plane is perpendicular to the length of the cable assembly. This rule applies whether the right angle connector is a standard, mitered or radius right design.