RF amplifier basics
A radio transmitter is a collection of stages. How these stages function determines the operational capability of each transmitter.
Fixing signal problems
When reception trouble is reported, it's not always easy to find the cause.
Building a better radiator
As public rejection of tall towers has increased, radio engineers have been paying more and more attention to AM antenna design requirements in an effort to develop shorter AM antennas that are as efficient as their taller brethren.
Environmental, ground system problems
As the FCC continues to delete mandatory measurements and checks from the Part 73 rules, some unintentional traps are opened for the unwary engineer.
Test your RF system
Modern equipment is stable and reliable, but some things should be checked on a regular basis.
DA maintenance
With the FCC's reduced logging requirements, there is no excuse for a directional array not to have adequately written maintenance logs.
Multitenant towers
The use of somebody else's tower can be attractive, but before rushing into a contract with an existing tower owner, consider all the problems that can occur.
Diplexing AM transmitters
When vertical real estate is at a premium, diplexing AM stations may offer an cost-efficient alternative.
Lightning protection
with proper engineering precautions, towers can survive intense lightning attacks.
Grounding and signal problems
Adequate grounding means different things to different engineers.
IBOC and combiners
Some transmitter manufacturers have already announced the availability of FM IBOC transmitting equipment, and offered actual equipment at the NAB show. FM IBOC requires considerably more equipment than the AM version, and it is more expensive.
Thoughts about IBOC
Many engineers anxiously awaited the release of the National Radio Systems Committee's AM IBOC Report, in hopes that the report would reveal good news about AM IBOC.
New tower standards
In the U.S., the joint TIA//EIA-222 standard oversees the design of broadcast and antenna supporting towers.
Tower maintenance
There are very few jobs in broadcasting where one can start at the top; but tower maintenance is the one where it is best to start at the top and work down.
Top loading, part 2 of 2
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.
Top loading, part 1 of 2
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.
Impedance matching
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.
Computerized planning and station engineering
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.
Thoughts on FM
I often wonder if Major Armstrong knew what he was giving to the world when he began developing frequency modulation as a public service.
Tall AM towers
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,
The licensing process
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
Detuning unwanted reradiators
Like mushrooms after a heavy rain, unwanted reradiators sometimes appear almost overnight in the near field of AM antennas.
Mutual impedance
Matters of impedance are deeply significant in radio engineering. In audio, with lower frequencies, the actual component values are generally considerably
Antenna basics
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
AM tower installation
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
