Monday Morning Coffee and Technical Notes

August 25, 2025 View as Webpage

Review of the ABIP Training Seminar

The ABA Engineering Academy conducted a two-day ABIP training seminar last week where 15 engineers from 5 different states learned all the details of items inspected during an Alternative Broadcast Inspection (ABIP). We were also excited to have two field inspectors from the Atlanta FCC office as our special guests.

ABIP inspectors John George and Larry Wilkins reviewed how the different items on the checklist are inspected.  On the second day we took the group to two different transmitter sites and conducted a mock inspection. Thanks to Tom Scott, Summit Media and John Bradfield, Sinclair for allowing us to conduct these inspections at their sites.



Both days were recorded and the video will be on the ABA Engineering Academy YouTube site in a few days.

ABA Engineering Academy Classes

A quick reminder that the next Radio Engineering Class is scheduled for the week of September 22^nd – 26^th. Classes are held at the ABA Training Center, 2180 Parkway Lake Drive in Hoover (Birmingham) AL. Class outlines, hotel information, and online registration are available at the Engineering Academy website.

A limited number of seats remain available; registration is still open.

The Television Class will be held November 3^rd – 7^th. 



Remember these classes are offered to anyone around the country and at no cost, as a service to the engineering community by the Alabama Broadcaster Association’s Engineering Services.

Reviewing the Rules – Remote Control

Let’s take a moment to review the FCC rules concerning the requirement to ensure that someone has continuous monitor and control of the station transmitter. Over the years how this is accomplished has undergone changes, internet, cell phones, etc., has opened various ways to monitor and control the transmitter.

However, the bottom line still remains, that a responsible person must be able to monitor the proper operation of the transmitter and should it begin to operate in a non-conformant mode have the ability to terminate transmission.

Section 73.1350 spells out the requirements in detail.

“The transmitter control personnel must have the capability to turn the transmitter off at all times. If the personnel are at a remote location, the control system must provide this capability continuously or must include an alternate method of acquiring control that can satisfy the requirement of paragraph (e) of this section that operation be terminated within three minutes.”



Paragraph (e) indicates, “if a broadcast station is operating in a manner that poses a threat to life or property or that is likely to significantly disrupt the operation of other stations, immediate corrective action is required. Examples of conditions that require immediate corrective action include the emission of spurious signals that cause harmful interference, any mode of operation not specified by the station license for the pertinent time of day, or operation substantially at variance from the authorized radiation pattern”.

Operating Power Measurements

Over the last couple of weeks, we have reviewed the procedures used to check and maintain the correct power level for non-directional AM stations and directional AM transmitter sites.

This week less look at monitoring transmitter output power for FM stations. FCC 73.267 indicates the operating power of each FM station is to be determined by either the direct or indirect method.

Section (b) of 73.267 explains that the direct method of power determination for an FM station uses the indications of a calibrated transmission line meter (responsive to relative voltage, current, or power) located at the RF output terminals of the transmitter. This meter must be calibrated whenever there is any indication that the calibration is inaccurate or whenever any component of the metering circuit is repaired or replaced.



The operating power measured by the indirect method is applying an appropriate factor to the input power to the last radio-frequency power amplifier stage of the transmitter, using the following formula:

Transmitter Output Power = Ep × Ip × F

Ep = DC input voltage of final radio stage (or supply voltage for solid state units).

Ip = Total DC input current of final radio stage (or total supply current for solid state units).

F = Efficiency factor as supplied by the equipment manufacturer.

If you are operating in IBOC (HD) using low level combining, the total will be the analog plus the injection level of the digital carriers. The percentage of the analog carrier created by the digital carrier can be calculated by the formula:

-20 dbc/10 = -2, then 10 raise to -2 = 1 percentage of analog

-14 dbc/10 = -1.4, then 10 raise to -1.4 = 3.98 percentage of analog

-10 dbc/10 = -1, then 10 raise to -1 = 10 percentage of analog

Normally the FCC doesn’t issue a new license with the updated TPO which includes IBOC.

Pro Audio –  Equalization

As tempting as it is to reach for the EQ knobs when mixing audio, take time to listen intently to the audio first. Listen and identify any sounds that should not be there, it may be hum, buzz, distortion, rumble, or other sounds. Of course some of the removal may require some EQ shelves to address low frequency rumble, that can’t be removed at the source.

Once all the offending sounds have been removed then concentrate on level and panning of the sources. Pay attention to what is the key source of the song, which of course can vary from song to song.

Then you can use EQ to balance sources that sit in the same frequency range. For instance, an electrical guitar has a lot of energy around 3kHz – 5 kHz, In the same song there may be a vocal which sits in the same frequency range. Using EQ you can make the two sit together correctly. The best approach however is to control competing frequencies in the arrangement of the music. A good guitar player knows to pull back during the vocal.

I can’t stress enough how important “proper arrangement” is for a successful mix. If the arrangement is bad there is just so much one can do at the console.

Not a good way to start a Monday!