Monday Morning Coffee and Technical Notes

February 24, 2025 View as Webpage

Primary Responsibilities of a Broadcast Engineer

All broadcast stations should have a “technical” person either on staff fulltime or contract to handle installation of new equipment and make necessary repairs and adjustments to maintain compliance with FCC Rules and Regulations.

Of course, the “engineer” should have the technical knowledge to ensure the station remains on the air with the highest quality audio and video as possible.

In addition to all the equipment at the studio, the Engineer should schedule regular visits to the transmitter site to review proper operation of the transmitter, tower lights, and other equipment. 

A maintenance log indicating the items observed and adjusted during these visits should be kept. This log is invaluable in keeping track of equipment service issues.

Directional AM Operation

As a quick reminder to engineers that maintain directional AM transmitter sites, the normal method of measuring the transmit power is to observe the common point current meter at the input of the phasor. 

Use the simple power formula: P = I² R, where P is the power, I is the measured antenna current and R is the impedance of the phasor which is typically 50 ohms.

The main thing to remember is FCC rules 73.51 (b) indicate that for stations with nominal powers of 5 kW, or less, the authorized antenna input power to directional antennas shall exceed the nominal power by 8 percent.

For stations with nominal powers in excess of 5 kW, the authorized antenna input power to directional antennas shall exceed the nominal power by 5.3 percent. This mpower is read at the input to the phasor equipment.

In addition, engineers should check the antenna monitor to ensure the current and phase ratios are correct. 

Part 73.62 states “Each AM station operating a directional antenna must maintain the relative amplitudes of the antenna currents, as indicated by the antenna monitor, within 5% of the values specified on the instrument of authorization.

Directional antenna relative phases must be maintained within 3 degrees of the values specified on the instrument of authorization”.!



Quite often new engineers may not be aware of these requirements. These items need to be on the check list each time you visit the transmitter site.

Most importantly, if readings are out of tolerance, don’t start turning knobs on the phasor. This can get you into trouble quickly! Incorrect readings normally are the result of a component failure.

Overview of the GSSNet Origination and Distribution System

In 2011 the Alabama State Emergency Communications Committee (SECC) in an effort to increase redundancy and reduce the number of “daisy chain” relays of EAS test and alerts, joined forces with Global Security Systems (GSSNet) to create and install a state-wide EAS satellite distribution network.



The SECC goals were to have a Common Alert Protocol (CAP) system with a secure web portal for use by the state agencies that are authorized by the Committee and approved by the Alabama Emergency Management Agency (AEMA).

The origination portal and distribution system was designed jointly by the SECC and GSSNet. The secure web portal allows the creation and origination of test and alerts either for the entire state or individual counties. The web portal is hosted by AWS and fed to the Microspace teleport in Raleigh North Carolina.

Presently the SECC has 44 downlinks installed at all the local EAS primary stations in the state, plus other selected full power FM stations. We are working on additional downlink sites which will bring our total to 50. The equipment installed at stations consist of a 1.2-meter dish and receiver manufactured by Wesport. The receiver communicates with Sage Endec via multicast protocol.

There is no cost involved for the station as all equipment and service is covered by various grants.



The system has been in operation for over 10 years and never experienced a major failure. Downlink equipment is monitored daily, and any issue or repairs are handled at no cost to the station. Our system has been approved by the FCC and is included in the Alabama State EAS Plan.

Proper Grounding Technics

I realize that there is still snow on the ground around the country, but it won’t be long till spring makes an entrance, bringing with it thunderstorms and lightning. Now is the time to review your operation grounding system.

Towers should be high (no pun intended) on the list of protection. A static dissipator system is a great technique that you should utilize to protect your valuable equipment and prevent off- air time. Key in proper installation is to have a drain cable bonding the dissipator to your station master ground. Here are some of the other things that ought to be in place:

1.   A star-ground system at the base of the tower using bentonite or chem-

rod ground.

2.   All transmission lines should be tied to the ground system at the base of

the tower, and at the entry point to the building.

3.   Surge protectors should be installed on the main power disconnect and

on each distribution panel in the building.

4.   If possible, use UPS backups with surge protection for all equipment.

5.   AM towers should have static drain chokes and properly set ball gaps.

6.   Most importantly, use a single point ground system. This means bond all

the equipment in the building together then take it out to the master

ground system. 

Planning ahead will safe a lot of time and money.

     Pro Audio –   Understanding SPL

SPL stands for Sound Pressure Level, which is a measure of the pressure of a sound wave in relation to a reference level. It’s expressed in decibels (dB) and is crucial for understanding how loud a sound is in various environments, whether it’s a concert, a home theater, or a professional studio.

Knowing SPL helps in ensuring that sound systems or recordings meet safety standards and are effective for intended purposes.

SPL is particularly important because excessive sound levels can lead to hearing damage, especially in environments where loud sounds are frequent. Conversely, too low of an SPL may result in poor sound clarity and listener engagement. Therefore, finding a good SPL level is essential for both health and quality of experience in sound-related settings.

SPL is a log scale, meaning that an increase of 10 dB actually represents a tenfold increase in acoustic power. For example, a sound measured at 0 dB is essentially the threshold of hearing for the average human ear, while a level of 120 dB can cause physical discomfort and even pain.

The SPL measurement involves using a microphone that detects sound waves, which are then translated into electrical signals. The readings are typically calibrated against a reference level of 20 micropascals, which is considered the quietest sound detectable by the human ear.

Determining the correct SPL for a particular venue is extremely important is creating a quality performance.



Read more about proper SPL here

Lot of DNA stored on that block!