When first developed, the Doherty amplifier gained a reputation for difficulty in adjustment and consistent operation. Since then, it has proven to be a stable and reliable transmitter design.
The basic installation of an AM IBOC transmitter is similar to that for an FM IBOC installation with varying exceptions required by the different system
What steps should you take when constructing a new facility for IBOC?
The directional antenna system is a unique balance of art and science. Keeping it in top operating condition will preserve the system's efficiency and likely keep it in compliance with the FCC.
The phasor is not the frightening cabinet of horrors that some engineers consider it to be. While it may seem daunting, a basic understanding of its operation will make maintenance of the antenna system much easier.
The closer the correlation between the modulating signal and the instantaneous value of the modulated carrier wave the better the quality of the eventual reproduction of the audio signal.
Most of the radio transmitters in use today depend on feedback, negative or positive, for their successful operation.
Sometimes we lose sight of the relationship between current in an antenna and the resulting field strength value.
Until the advent of FM, combiners were rarely required. After FM was introduced, the need for a method of feeding two or more FM frequencies into a single
The IBOC system for FM as developed by Ibiquity is a fascinating engineering feat.
Despite the hiatus in nighttime operation for AM IBOC, antenna research is continuing in an effort to comply with the FCC's existing requirements of two antennas for FM IBOC, and develop a system using one antenna that will satisfy the FCC's requirements.
Because of inductive and capacitive circuits, it is often easy for undesired and usually unwanted oscillations to be generated in an amplifier stage. Neutralization is important to keep these systems at maximum efficiency.
A radio transmitter is a collection of stages. How these stages function determines the operational capability of each transmitter.
When reception trouble is reported, it's not always easy to find the cause.
As the FCC continues to delete mandatory measurements and checks from the Part 73 rules, some unintentional traps are opened for the unwary engineer.
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.
Modern equipment is stable and reliable, but some things should be checked on a regular basis.
With the FCC's reduced logging requirements, there is no excuse for a directional array not to have adequately written maintenance logs.
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.
When vertical real estate is at a premium, diplexing AM stations may offer an cost-efficient alternative.
with proper engineering precautions, towers can survive intense lightning attacks.
Adequate grounding means different things to different engineers.
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.
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.
In the U.S., the joint TIA//EIA-222 standard oversees the design of broadcast and antenna supporting towers.