Ed Murlatt & Associates, Inc.
RF Services for the Broadcast Industry
DTV Transmitter PM - Benefits
Our preventive maintenance visits help keep the transmitter in peak operating condition.  We often locate and repair problems before they occur.  In addition to making certain the transmitter is operating as efficiently as possible and is providing the optimum signal performance, we have a list of common failure points we inspect while on site.  We also point out these high failure areas to station personnel so they can have a jump start on troubleshooting future problems.  For IOT transmitters, we record tracking data in an Excel workbook that maintains the operating parameters of the IOT across time.  We like to leave copy of this workbook with the station engineer's use in maintaining the transmitter.  We verify amplifier tuning and make adjustments where necessary.  A complete report is provided for future reference.

Click here for a look at the IOT data we record.

Click any of the thumbnails below to see some sample tuning and harmonic measurement plots in a new window (harmonics as measured at the IOT output NOT after the harmonic filter).  It is important to keep harmonics a minimum of 30 dB below the fundamental, as measured at the IOT output. 
Input tuning across 20 MHz Output tuning across 20 MHz Output tuning across 10 MHz Harmonics
Click the thumbnails below to see some sample ATSC performance measurements in a new window.  Measurements we made with the receiver EQ off.     
constellation no eq measure list no eq Shoulders vsb no eq
Sometimes bad things can happen to good transmitters.  We stay in contact with our colleagues and manufacturers to try to help avoid these problems.  Have a look at some of the failures we've witnessed.