Part One described the events leading to the development of top loading of broadcast AM antennas. This part continues with details of the types of top loading and discusses the use of the FCC's Rules in planning a top-loaded antenna system.
Engineers charged with the job of designing a new AM transmitter facility nearly always try to plan for the tallest tower possible. This is not just an ego trip; it's because the taller the AM radiator, the higher the field strength developed in the listening area with a given power.
We have all been taught that the load impedance must match the generator impedance in the case of non-DC voltages in order to obtain the most efficient transfer of power. In DC work it seems that loads with an improper resistance fail to work because the supply voltage is too low, or else burn out because their resistance is too low for the applied voltage, and simple Ohm's law applies.
In the early days of radio engineering, it was necessary to calculate every value used in determining coverage and antenna design manually. Slide rules were the norm, and many engineers carried one in a hip holster -- well, almost. My slide-rule case certainly had a belt slot in it.
I often wonder if Major Armstrong knew what he was giving to the world when he began developing frequency modulation as a public service.
Usually, bigger is better. But in the case of AM towers, taller is not always better. A very tall AM radiator is not always the best radiator. In fact,
Whoever said, the more things change, the more they remain the same, must have had the FCC in mind. More than 50 years ago, Form 301 was thin and did
Like mushrooms after a heavy rain, unwanted reradiators sometimes appear almost overnight in the near field of AM antennas.
Matters of impedance are deeply significant in radio engineering. In audio, with lower frequencies, the actual component values are generally considerably
The author Gertrude Stein once said a rose is a rose, is a rose is a rose. Maybe an antenna is an antenna, is an antenna also applies, but an AM antenna
If you have the good fortune to be responsible for the installation of a directional AM station, you will find that there are many important details that
Most radio engineers will agree that after the antenna and ground system, transmission lines are probably the most neglected item. For both AM and FM,
Many test instruments have been developed in the history of broadcast engineering. Some have had brief lives; others simply filled the needs that many
A radio engineer's definition of a parasite might be something that obtains its power from another's energy. In other areas of broadcast engineering it
One phenomenon common to transmitter installations does not always receive the attention it warrants. Voltage standing wave ratio (VSWR) can wreak havoc