As cellular towers began to proliferate, the interference to broadcast antenna systems became apparent, and AM broadcasters sought redress from the FCC.
Examine some ideas and items to look for in the budgeting and planning process as they apply to FM and AM antennas.
The most daunting task of IBOC has been how to combine the analog and digital signals in a cost-effective manner. Dielectric believes it has the answer.
What steps should you take when constructing a new facility for IBOC?
Although no amount of security can deter a determined intruder, a burglar will definitely look for an easier target rather than risk being slowed down by a facility’s defenses and be caught in the act.
Sometimes we lose sight of the relationship between current in an antenna and the resulting field strength value.
It may seem that a typical broadcast facility doesn't have all the safety concerns of a construction site or a manufacturing facility, but accidents happen.
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
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.
The Durst Organization, the real estate management company of The Condé Nast Building (4 Times Square) in New York City has undertaken the massive project of tripling the height of the tower high atop the building, coming into its own as a premier transmission facility.
KKXS, Shingletown, CA, improves its signal with a new antenna. Read about it in this review.
When problems of abnormal VSWR occur, they generally result from mechanical or electrical damage due to the transmission line or antenna, and frequently to heavy ice formation on the antenna.
The fundamentals of the folded unipole have not changed much since 1952, but experience has provided several improvements as well as some weaknesses.
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.
A variation on the antenna's construction.
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.
Build a shielded-loop AM antenna.
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.
One of the advantages claimed for the folded unipole is its broad bandwidth. However, years of experience have shown that this can vary greatly depending on several factors, mainly overall tower height.
The article titled "Transmission: Implementing IBOC" in the October 2001 issue of BE Radio is very informative, but one concept in it may need further clarification.
UK tests will wait a little longer.
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,
Discussions with FM engineers unearthed concerns about radio's future when considered with reference to streaming, DAB/IBOC, RBDS, satellite radio, and
Like mushrooms after a heavy rain, unwanted reradiators sometimes appear almost overnight in the near field of AM antennas.