ABSTRACT
Parallel tubing (air dielectric) 0.95
Coaxial line (air dielectric) 0.85
Coaxial line (solid plastic
dielectric)
0.66
Two-wire line (wire with plastic
dielectric)
0.68 to 0.82
Twisted-pair line (rubber
dielectric)
0.56 to 0.65
Table 2.3 Velocity factor for various types of feeder
Figure 2.40 Coaxial connectors (from left to right: PL-259, BNC, and N-type)
Figure 2.41 Method of fitting a BNC-type connector to a coaxial cable
Connectors provide a means of linking coaxial
cables to transmitting/receiving equipment and
antennas. Connectors should be reliable, easy to
mate, and sealed to prevent the ingress of
moisture and other fluids. They should also be
designed to minimise contact resistance and,
ideally, they should exhibit a constant impedance
which accurately matches that of the system in
which they are used (normally 50 Ω for aircraft
applications).
