Solid-state, digital exciter
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.
For towers that require incandescent lighting, regular tower-light inspection and maintenance is a task that tower owners must undertake. The annoyances lie in changing a burned-out lamp, affording the cost of a tower climber, timing convenience of the failure.
Solid-state technology has taken over the major AM broadcast transmitter manufacturers, and up to 40kW of solid-state power is available in FM. When making the decision to buy a new transmitter, there are several factors to consider.
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.
In November 2000 the Commission created a new FM channel classification to join Classes A, B, B1, C, C1, C2 and C3. Use of the new class - Class C-0 (C-Zero) - permits upgrades of existing stations and new allocations based on the reduced spacing protections, which will apply when Class C stations are converted to Class C-0.
Part 1 of our Special Report.
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.
When Northwestern College Radio acquired WMAD, one of the first priorities was to replace the transmitter. Mark Croom reviews the AM-1A.
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.
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.
Transmitting several frequencies from a single broadband antenna system requires the use of a combining system, or combiner, composed of RF filters and interconnecting transmission line. Generally, a combiner can be categorized as branched (star point) or balanced (constant-impedance). These types may use band-reject (notch) or band-pass filters.
It's a cool Monday morning; the first in October, in fact. After opening your office, and after downing the requisite two cups of coffee, you turn on your computer and open them: The dreaded capital budget spreadsheets.
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.
In an ever-evolving effort to smooth the transition from analog to digital technology, the Federal Communications Commission is proposing to revise its rules to allow broadcast auxiliary services (BAS) to convert to digital technology along with broadcast stations.
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,
Discussions with FM engineers unearthed concerns about radio's future when considered with reference to streaming, DAB/IBOC, RBDS, satellite radio, and
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
Incrementally or all at once, the transition is coming. How digital is your facility?
Like mushrooms after a heavy rain, unwanted reradiators sometimes appear almost overnight in the near field of AM antennas.
At some point in an engineer's career, questions such as How does our signal compare to so-and-so? or, Have we increased multipath along the highway lately?
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