Where is my radio signal?

Radio-Tower

Dear Christian Radio,

It is 2:00 in the morning and your radio station is off – what do you do?  No, you don’t call the Ghostbusters.  Who you call or what you do is really dependent on your individual situation at your radio stations.  Do you have a faithful contract engineer, a full-time engineer, a staff engineer on duty, or are you like many Christian radio stations across the country that don’t have quick and ready access to a technical staff member?  If that is the case, you as the employee or general manager may be asked to bring the station back on the air yourself.

We will discuss some good procedures for troubleshooting your off-air emergency.  Where do you even begin to start?  First, as with all things, safety to you and others is the most paramount principle when working around electronics, electrical systems and transmitter sites.  You must obey all safety regulations from local, state & federal municipalities.

Secondly, in engineering it is good to understand the different steps in your air chain to understand how your radio station content is delivered to your listeners.  Understanding the air chain will help you to quickly diagnose problems.  You can work backwards from your listener’s perspective or forward from the beginning of the studio to find the problem.  Let’s go through different problems from different perspectives…

Scenario A — diagnosed backward method from the listener’s perspective:  The radio station is off the air and there is “dead air”.  That means that you have perfect silence when you listen on your radio.  If this is happening, you can work backwards and assume that the transmitter is on because if it wasn’t, your listeners would be hearing static or another radio station instead of yours.  Now, you can start working backwards through your air chain to find the problem.  Next, you should determine if you have audio being delivered to the transmitter site by way of microwave STL, telephone T1, DSL, spread spectrum system, or by cable wiring for a co-located studio and transmitter site.  You find that your T1 delivery method has a failure and you contact the local phone provider to solve the issue.  If you didn’t find the problem there, you would work your way back through equipment at the studio including EAS, consoles and your automation system (if applicable) to find where the failure is occurring.

Scenario B – diagnosing forward method:  The radio station is off the air and there is “dead air”.  You know from the previous example that perfect silence means that the transmitter is on and operating but without any audio.  You start from the front of your air chain with the console and automation system. Bingo!  The first thing you see when you look at the automation is an operating system failure.  You have found your failure and do not need to diagnose any further.  However, if you didn’t find the problem there you would continue through the air chain in the direction that the audio is traversing.  You would then check the EAS equipment, audio delivery method to the transmitter site, & any other systems in your air chain.

Scenario C – diagnosing backwards method:  The radio station is off the air and your listeners are hearing another radio station from 40 miles away on the same frequency on which you broadcast.  This is considered a “static” off air emergency and not a “dead air” situation.  This indicates to you that the transmitter is off and that any number of systems before the transmitter could also be off.  The first step to take is to visit your transmitter site or check your transmitter remote control (if applicable).  You need to determine if you have power at the transmitter site or if you are without power (and without backup power generation systems).  If you don’t have power or an operational backup power generation system, your transmitter and station are off the air because of that reason.  If you do have power, your transmitter could be off the air because of a failure to that system.  In this case, your power was off because of a large tree across the power lines at your transmitter site.  You call the electrical company and wait for them to restore electrical service to your location.  In the event of a transmitter failure, please consult with a technical advisor such as a contract engineer, staff engineer or the transmitter manufacturer to determine your best course of action.  Again, the transmitter system can be the most dangerous and should only be operated by trained individuals who are familiar with safety measures.

These are a few situations that can commonly occur with your radio station.  With experience, you can start to skip steps when you know what your common points of failure are in the air chain.  If you follow these strategies, you can start to diagnose your off-air emergencies in a safe and efficient manner.

Dear Christian Radio, here are some key ideas for you to remember:

  1. Safety comes first.
  2. Work either forward or backwards through the air chain to diagnose.
  3. Determine if you have a ‘static’ or ‘dead air’ off-air situation

David Hodges, Director of Engineering
Positive Alternative Radio

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