A
Caring for Connectors
68
Keysight N4000/1/2A Operating and Service Manual
Mechanical Specifications
The critical dimension to be measured, regardless of connector type, is the
position (generally, the recession or setback) of the center conductor relative to
the outer conductor mating plane.
Mechanical specifications for connectors specify a maximum distance and a
minimum distance that the center conductor can be positioned behind (or, in
female Type-N connectors, in front of) the outer conductor mating plane. Nominal
specifications for each connector type exist, but the allowable tolerances (and
sometimes the dimensions themselves) differ from manufacturer to manufacturer
and from device to device. Therefore, before gaging any connector, consult the
mechanical specifications provided with the connector or the device itself.
Precision 7 mm connectors
In precision 7 mm connectors, contact between the center conductors is made by
spring-loaded contacts called collets. These protrude slightly in front of the outer
conductor mating plane when the connectors are apart. When the connection is
tightened, the collets are compressed into the same plane as the outer
conductors.
For this reason, two mechanical specifications are generally given for precision
7 mm connectors — the maximum recession of the center conductor behind the
outer conductor mating plane with the center conductor collet removed; and a
minimum and maximum allowable protrusion of the center conductor collet in
front of the outer conductor mating plane with the collet in place.
The center conductor collet should also spring back immediately when pressed
with a blunt plastic rod or with the rounded plastic handle of the collet removing
tool. Never use a pencil or your finger for this purpose.
With the center conductor collet removed, no protrusion of the center conductor
in front of the outer conductor mating plane is allowable, and sometimes a
minimum recession is required. Consult the mechanical specifications provided
with the connector or the device itself.
