Monday Morning Coffee and Technical Notes

February 17, 2025 View as Webpage

ABA Engineering Webinar

Here is a special invitation to join us tomorrow February 18^th for our monthly Engineering Webinar. This month will have a most interesting “round table” discussion of “How we got to where we are today”.

John George, Bob Mayben and Larry Wilkins will talk about things we used to use at our radio and television stations that are no longer a part of the system. I know there will be some humorous stories about things we use to do as well.



Register Online here and join us at 10:00AM central time.

As a reminder, all our monthly webinars along with other videos are available on the ABA Engineering Academy YouTube channel

The Broadcast Engineer

There are three important traits that broadcast engineers need to develop to become efficient in their career.

First…They need to have a solid understanding of basic electronics. Although technology has progressed over the years, basic electronics is still working behind the scenes. Things like ohms law, frequency and wavelength, components like resisters/capacitors/inductors are all important.

Second…Engineers need to understand the devices used in their facilities. What they do, why are they used and how do they improve the program for the listeners and viewers. Sometimes you may find that there is a piece equipment that is not adding anything to the presentation or efficiency of operation and as such can be removed. In our business “less is more”.



Third…Engineers should create a desire to become a “lifelong learner”. With technology changing at such a tremendous rate, it is imperative that engineers keep up. The ABA with its continuing education series of monthly webinars and seminars is a great asset in this area. 

ABA Engineering Academy

The ABA Engineering Academy will offer our Radio Engineering Class the week of February 24 – 28, 2025. The Television Class will be held the week of April 28 – May 2, 2025. We will offer a second round of classes later in the year.

The class will cover basic electronics, analog and digital audio, history of radio broadcasting, AM and FM transmitters/antennas, EAS and FCC rules. We also offer the opportunity for students to take the SBE Certification exam on Friday.

Classes will be held at the ABA Training Center 2180 Parkway Lake Drive Hoover, AL (Birmingham). Classes are offered at no cost for beginners or seasoned engineers from across the country.



Daily class outlines and registration is available at the ABA Engineering Academy website.

CALM Update

The FCC released a draft of a Notice of Proposed Rulemaking proposing a review of the rules adopted to implement the Commercial Advertisement Loudness Mitigation Act of 2010 (CALM Act), which was intended to protect viewers from excessively loud TV commercials. 



This draft will be considered at the FCC’s next regular monthly open meeting on February 27. If the NPRM is adopted, based on thousands of viewer complaints received about the continuing loudness of TV commercials, the FCC will be seeking comment on whether the FCC should update or change its CALM Act regulations – including whether to extend the rules to cover commercials on streaming.

 Understanding OFDM

As ATSC Continues to make its way into our television operations, it is important that engineers absorb as much information about this “next generation of television transmission. One of the main items to understand is OFDM “Orthogonal Frequency Division Multiplex.

The word orthogonal indicates that there is a precise mathematical relationship between the frequencies of the carriers in the system. In a normal frequency-division multiplex system, many carriers are spaced apart in such a way that the signals can be received using conventional filters and demodulators. In such receivers, guard bands are introduced between the different carriers and in the frequency domain, which results in a lowering of spectrum efficiency. 

It is possible, however, to arrange the carriers in an OFDM signal so that the sidebands of the individual carriers overlap, and the signals are still received without adjacent carrier interference. To do this, the carriers must be mathematically orthogonal.



In OFDM, the subcarrier frequencies are chosen so that the subcarriers are orthogonal to each other, meaning that crosstalk between the subchannels is eliminated and intercarrier guard bands are not required. This greatly simplifies the design of both the transmitter and the receiver. In conventional FDM, a separate filter for each subchannel is required.

The basic idea of OFDM is to split high-speed data to low speed

parallel channels. Longer symbol duration is the way to combat with multipath fading.

   Pro Audio –  Dealing with Latency

One of the easiest ways to improve latency is to adjust the buffer size and sample rate within your DAW. These two things directly affect how the latency is set and how fast samples are being recorded. If you like math, here’s an equation that will give you a general idea of latency in a typical ASIO configuration.

Just divide the buffer size by the number of samples per second (sample rate). For example, if you have your buffer size set to 256 and your sample rate at 48 kHz, divide those two and you’ll get 5.3 ms. If you change the settings to 512 and 48 kHz, however, it’ll average out to 10.6 ms.

A lower buffer size will create less audible delay but will make your computer work harder.

A higher buffer size will create more audible delay but will free up resources for your computer to use on other processing tasks.



A good rule to remember when it comes to buffer size is low for tracking, high for mixing. You want a lower buffer size when tracking to ensure minimal delay. But when you’re mixing, you want to raise the buffer size so the computer can process a wider scope of tasks (such as processing a lot of plug-ins).

"Good Advise"