Engineering

Reliability and Redundancy

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Reliability definition

The two words, “reliability” and “redundancy” are the key principals behind assuring that your radio station is broadcasting twenty-four hours per day.  Ideally, our radio stations would be on the air every second of every day but that is never physically possible.  However, there are many steps that can be taken and systems that can be built to reduce the amount of time off the air.

Reliability is measured by the amount of time “on the air” at your radio station.  For our radio stations, we want that number to be somewhere between 99.9% and 99.99% on the air.  That corresponds to between four and forty-four minutes of downtime on average per month.  99.9% is very good but 99.99% would be considered about the highest echelon of reliability that we can achieve.

We achieve redundancy through two different methods: having good quality equipment/systems that we can trust and building redundant backup systems to our main operations.

High quality equipment and systems is paramount to providing a high level of reliability.  To do so, we must invest in equipment that is robust and not prone to failures.  Equipment and systems that are prone to failure should be replaced with improved systems or redundant backup systems.  High quality equipment in the main air chain of the radio station should be business class quality and not consumer grade.

Redundancy is the next step to providing a high level of reliability for your radio station.  Redundancy systems at the radio station will increase your reliability by providing an alternate system to your normal operations, to compensate for a failure.  One common example is an emergency standby generator at your studio or transmitter site.  A generator system will monitor your power provided by the power company and in the event of a failure, it will start the generator.  The generator will provide an alternate source of electrical power to your location until the power company can restore service.

In addition to backup generators, there are many other systems that can be built to increase reliability through redundancy to your radio station:

a)      Backup studios in which to broadcast in the event of a major failure in your main studio

b)      Backup programming on CD or computer that can be played in the event of an automation computer failure

c)       An auxiliary broadcast antenna and/or transmitter site in the event of a major failure at your main transmitter site

d)      Backup transmitter at your main transmitter site in the event of a failure on your broadcast transmitter

e)      Alternate signal delivery methods from the studio to your transmitter site such as an Internet backup to your microwave audio delivery, satellite or telephone line

f)       Audio switchers in your studios that can bypass a console or piece of equipment in the event of a broadcast console failure

All of these systems have the same purpose — to keep you on the air.  These systems can seamlessly and automatically switch to backup systems in the event of a failure which will greatly reduce the amount of time off the air and improve your reliability.

David Hodges, Director of Engineering
Positive Alternative Radio

Where is my radio signal?

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I wanted to take this opportunity to address a few questions that our teams and listeners have concerning radio reception. It’s the age old problem that we hear all the time – “I can’t pick up the radio station.” There are a number of different reasons that this happens and I hope that I can help others to learn some of those reasons and how we can fix those issues.

Each of our radio stations has a studio where our staff operates. However, in most cases, we are broadcasting from a radio tower in a different location. The tower location, transmitter licensed power and signal direction was chosen because of engineering restrictions placed on our radio stations by the Federal Communications Commission (FCC).

Question: Why do I hear other radio stations instead of your radio station on some days?

Answer: One plausible reason is an effect called tropospheric ducting. This is a weather event often caused by cold & warm fronts in your area. These temporary events will cause radio stations from other parts of the United States to be refracted off the tropospheric layer of the atmosphere and into your community. So, instead of hearing your normal radio station, you will hear a radio station on the same frequency from a different area (even the other side of the country). The interference usually goes away within a few hours time but could re-occur in the surrounding days as well.

Fix: This cannot be fixed or alleviated. The only option is to wait for the weather event to finish.

Question: Why can’t my town have a better radio signal?

Answer: This is a quite complex question and one that we often get asked. I mentioned above that the FCC regulates the transmitter site location, power and in which direction you broadcast. This makes our radio stations part of a big puzzle alongside all the other radio stations in the country. Moving a transmitter site, increasing power or changing direction in which you broadcast is like shifting that puzzle around. Any of those changes require that we will not interfere with another radio station that is on our transmitter frequency or near our frequency. The FCC will not allow us to apply for any change that will interfere with another radio station.

Fix: If there is a community that is having troubles with signal reception, please document those issues for station management and engineering team members. Engineering studies can be conducted to determine if any changes can be made to the radio station to allow for better reception.

Question: Why does one radio signal have coverage over 10 miles while another one has 50 miles?

Answer: The FCC grants certain classifications for radio stations. These classifications determine how far the station can be heard. Full-power radio stations can have a listening radius of 25-75 miles dependent on the classification of the radio station. FM translators are licensed to individual communities and are classified to broadcast to a small area such as a 5-10 mile radius.

Fix: Engineering studies can also be conducted to determine if any changes can be made to the radio station to allow for better reception. Please document those issues with station management and engineering team members for further examination.

Question: Why can’t you apply for a new frequency & station in my area?

Answer: The FCC occasionally conducts auctions for individuals and groups to apply for new radio stations. The last auction for non-commercial, FM radio stations was in 2007. You cannot apply for a new non-commercial, FM radio station outside of that window and there are no new auctions at this

Fix: Without an FCC auction, the only real option is to acquire or move an existing radio signal into that area. Please document those issues with station management and engineering team members for

Question: Why can I hear you on my car radio but not inside my home?

Answer: There are many factors as to why this occurs but they all relate to signal reception. The more signal you have, the less static you will receive when listening to the radio station. You will have more signal outside your house or business because the radio signal weakens as it travels through walls. Also, clock radios and small handheld radios have more discrete antennas that will not receive as much signal as a large antenna on your car would. Furthermore, car manufacturers are now placing smaller antennas on cars or using antennas built into the back window of your car which don’t receive as much

Fix: There a few different options out there for radio reception inside your house or business. One option is online web streaming with your PC, mobile device or Internet radio. A desktop Internet radio will receive the radio station through your home/business Internet connection. A second option for better FM reception in your home is to purchase an FM antenna that will interface with your home radio. This will give you a better chance at receiving the station than the small antennas that are located on clock or handheld radios.

 

David Hodges, Director of Engineering

Positive Alternative Radio