IAN LANG ELECTRONICS

With a severe standing wave, at best the signal will be highly attenuated. At worst we will destroy the output stages of the transmitter, and if it is a high power one disastrously so. Altering the matching unit should improve the ratio. When there is no reflection,  the system is balanced; the meter should read "1" or "1:1".

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Connecting the Feeder:

 

Below is a drawing of coaxial cable and a BNC connector for it:

Belling-Lee or IEC 169-2 connector

 

PL259 connector (left). Both the Belling-Lee and the PL259 do not have such a uniform impedance over the connector as do the BNC and N types but they do have the advantage of being much  cheaper. The Belling Lee is used mainly in consumer goods, the PL259 is found in use by Radio Amateurs.

 

The BNC is a common connector  and is used  wherever a semi-permanent connection needs to be made, as it gives a good mechanical link and locks and unlocks quickly and easily. For more permanent an N connector may be used,  this has  a screw thread  rather than a bayonet fitting. At lower powers a PL259 may be used, or even a Belling -Lee such as goes into the back of the television. This has the disadvantage that it does not lock, but mechanically it is very good;  it is the oldest form of RF connector still being used (since 1922).

Radio Principles