Broadcast Australia Site, Mt Mowbullan, Queensland. Photo Credit: John Giulieri
By Stephen Heazlewood, Senior RF Systems Engineer and Systems Automation Lead, Broadcast Australia
In today’s digital world, people expect high speed connectivity wherever they are. For transmission network providers this means there’s no room for non-essential shut downs for maintenance, repair or replacement of equipment. Seamless connectivity is especially important for people living in regional areas where they rely on transmission networks for access not only to radio and television broadcast services but also to emergency and government services.
With this in mind, Broadcast Australia is continually encouraging employees to think of innovative ways to deliver more benefits to our customers. I was recently recognised for doing just that. I was invited to contribute a chapter on antenna testing methodologies to the leading industry publication, National Association of Broadcasters (NAB) Engineering Handbook, which introduces the methods I’ve been developing and fine tuning throughout my career in the broadcast and telecommunications industries.
Key to this is using methods which help ensure broadcast transmission systems run as efficiently as possible, and any maintenance or testing can be done with absolute minimum impact to our end customers. This therefore helps to ensure quality and continuity of service for their audiences.
Antenna systems are critical to the delivery of our broadcasting service and it’s important that we understand the health of the system to minimise the risk of transmission failures. In the past, transmitters had to be switched off for quite significant times, generally hours, whenever the antenna needed testing. Specialists would manually carry out measurements on site, diagnose issues with the system on the spot and drive the correct response to any issue they observed. This was a significant resource limitation and required repeated interruptions of services to our customers.
Our new methodology enables us to proactively determine a multitude of issues before they arise so our customers, like ABC, SBS and commercial broadcasters, and the services they provide, aren’t disrupted.
If we look through a more technical lens, one of the key strengths of our new methodology is that it allows technicians to take system measurements in a small outage window, typically less than an hour. This allows the system to be post processed using the actual recorded data from the test equipment and assessed after the measurement has been made and the systems are back in an operational state. Post processing is performed by technicians on site and analysts who can provide deep insight without having access to the test device that took the measurement, which are typically expensive and not easily accessible.
While post processing measured data isn’t new, we’ve coupled testing methodology which combines a physical assessment process as well as an analysis and modelling platform. This not only speeds up the process and better informs our understanding of the health of the antenna system, but it allows us to objectively quantify the operational efficiency of the system.
In the past, measurements were taken by looking at the system from a frequency response plot or a Time Domain Reflectometer (TDR) plot. Both provide limited insight and the antenna system can appear out of specification, or it may require further investigation by a specialist team due to simple things like the change in test location, a test connector not done up tightly enough, or over tightened. Our new approach enables us to detect and advise the technicians when their cable or adaptors are faulty, or when setup values are incorrect. We can see the impact of these contributors and the performance of the systems without these issues.
We’ve put tools in place so that when a potential issue is observed through this process, we’re able to model solutions and see how they’ll impact the system’s performance. A good example is the addition of a tuning section or a feeder replacement after damage. We accurately predict the system’s performance after the change and assess the benefit before we attend site and implement. Being able to distribute the information to a team of specialists and technicians for investigation yields diversity in practical solutions, which then allows us to understand their benefits and select the correct course of action.
This proven approach has enabled us to better understand the health of the antenna system on a macro level and how the major components of the system are performing individually. As a result, we’ve been able to deliver a lot of positive change for our customers and their audiences.
As testing methodologies continue to develop and systems become more connected, the next step for our team here at Broadcast Australia is looking at new areas, like machine learning, coupling systems and processes and data together to search for the best for our business and our customers. Watch this space – there are exciting things to come.