Ed Murlatt & Associates, Inc.
RF Services for the Broadcast Industry
Benefits of Scheduled Maintenance Visits
Proper preventive maintenance can reduce the potential for downtime, and improve transmitter efficiency and signal performance.  Years ago stations signed off every night for transmitter maintenance, and their engineers were inside the transmitters on a nightly basis, gaining knowledge and hands-on experience that cannot be replaced by a manual.  We service dozens of transmitters every year, providing an experience base that cannot be duplicated on the station side with today's 24-7 on-air schedule.  We compare notes with our colleagues, as well as various manufacturers adding to our knowledge base.  Over the years, the lists of things we check on all makes of transmitters has grown exponentially. 

We share tips and discuss what we are doing with station personnel during the course of our schedule maintenance visits.  Since even the best preventive maintenance programs cannot provide 100% reliability, the information we share helps prepare station staff for their opportunities to excel.  Links below will take you to a few pages on this site that show more reasons to sign up for scheduled maintenance.  While the overwhelming cost savings lies with avoiding costly catastrophies and lost air time, stations participating in our scheduled PM enjoy a slightly discounted service rate, and since the PM visits are scheduled, travel expenses for the preventive trips are shared with other participating stations, adding to the instant cost savings. 

Maintaining your RF system with periodic inspections is extremely important.  Usually, by the time a transmitter reports a problem with VSWR, considerable damage to the RF system has already occurred.  Moreover, it has become very popular amongst transmitter manufacturers to provide a foldback "feature" to keep the transmitter on the air at a lower power.  This often produces results "The Colonel" would have called extra crispy.  Periodic sweeps can help reduce the potential for catastrophe.  Here is more on RF system periodic maintenance.

If your transmitter has IOT amplifiers, the tuning will drift with time.  Keeping the IOT tuning optimized improves efficiency, and can improve shoulder response and SNR.  Often, we can reduce operating current slightly which results in lower power bills.  Improvements to SNR result in improved reception. 

Here's more on DTV transmitter PM

Here's more on maintaining cooling systems 

Even if you chose not to participate in our preventive maintenance program, we strongly recommend having assistance with IOT or IOT cavity replacement.  IOTs are too expensive to risk, and once every five or more years is not sufficient experience.  We also recommend having assistance with IOT grid out-gassing, or at a minimum during the first out-gas.  IOTs have been damaged due to improper out-gas techniques.