Transmisson
Forgotten modulation methods
Early in the 1930s French engineer Henri Chireix devised an ingenious method of modulation that he named most appropriately out phasing. It was based on the result of combining two out-of-phase voltages. This produces a fluctuating signal voltage that varies in amplitude as the audio signals change. This voltage, after amplification, drives a power amplifier stage with properly amplitude-modulated RF.
Tennessee Turnaround
WKNO-FM, an NPR member station in Memphis, began operations on April 1, 1972, on 91.1MHz with 40kW of effective radiated power. The station launched its HD Radio signal in the fall of 2007. Up to that point, we underwent incremental upgrades and adjustments to the original installation.
Radio broadcasting and 700MHz
The FCC is auctioning what may be the most important spectrum allocations of our time. This portion of spectrum will be available as a result of the FCC mandate for traditional analog broadcast television to migrate to the new digital HDTV system by Feb. 17, 2009, specifically the portion previously occupied by channels 60-69.
Don't become a statistic
There are many lists extant of precautions to take before working with high voltage pieces of equipment. Lethal incidents may be more often caused by completely unexpected circumstances than from pure, careless accidents.
A break from Tradition: Using IP for an STL
A station's studio to transmitter link (STL) is an integral part of its mission-critical transmission system, linking the site that generates the program material to the transmitter location itself. As such, the quality and reliability of STL equipment has always been of paramount importance. One critical aspect of an STL system has historically been lack of contention in its use.
Performance evaluation
With HD Radio, it's important to monitor and measure the time alignment and level alignment between the analog modulation and the MPS, and stations will likely want to monitor the RBDS on the analog channel along with PAD data for both the MPS and SPS. Fortunately, there are now multiple monitoring devices made specifically for HD Radio, and each of these devices gives the end user options about which parameters are to be measured, and how the device is to alert the user once a problem is detected.
NAB Trains Engineers at NAB AM Antenna Computer Modeling Seminar
The NAB AM Antenna Computer Modeling Seminar held at the NAB headquarters in Washington, DC, the week of Nov. 12, 2007 attracted 45 engineers.
RF filters
Radio-engineering work is very involved with filters of one kind or another. The science of broadcasting depends on the correct passage of various frequencies through differing pieces of equipment. Some frequencies are in the audio range and others are in the RF domain.
Wi-fi antennas
In recent years, the introduction of wireless networks allows users to work anywhere within a defined location. The technology behind wireless networks changes almost yearly, but one thing remains the same: the antenna.
LEDs Are Here to Stay
Tower lighting requirements, which are specified in part 17 of the Commission’s rules, sometimes come as a financial shock.
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