[W8MWA] RF Interference/Broadband Noise in Morgantown

[Werntz, Charles]

Thoughts on the "interference" in Morgantown - and some ideas to track it down.

Current Data:
- Over the past few weeks there have been episodes of interference occurring on the '43 repeater.
- At my house (near WVU law school) I hear intermittent broad-band interference that can be heard on a variety of VHF frequencies.  Saturday evening I heard the noise, Sunday it was gone.
- The signals do not sound to me like paging, as there are no "frame" tones.  (If you listen to a paging system, (152.0075 or 152.480 MHz) you will hear a series of tones every few seconds that tells the pagers to pay attention.) 
- When the interference is "present" is seems to be present for several hours at a time, perhaps even a day.  To my mind, this represents either a data channel that is used intermittently or some sort of equipment that is on at some times and off at other times.  Many data systems use one of several channels for their data stream, alternating every now and then to give each transmitter generally the same amount of use.  The data channel could be a cellular data system (any carrier), one of the data channels from the WV Interoperable system, the new WVU VHF trunked voice system, or some industrial or scientific process, or ???.

Thoughts:
- Due to its broadband nature, I don't think this is intentional (unless someone is testing or using a commercial jammer) 

- When you hear the interference, look for correlates. Time of day, how long does it persist, etc.  One thing I will look at is which data channel is the WVIRP trunked system using in Morgantown (Primary or Alternate).  Other folks may think of other things to check.  This will be harder if it is one malfunctioning transmitter of two on the same frequency, for something like a paging system.

- When there is interference on the repeater, switch over and note if you can hear it on the repeater input - How loud is it?  Do you note it in some areas and not others?

If we can figure out which transmitter has the issue than we can hopefully get it fixed.

I welcome any data or information or thoughts anyone wished to share.

Carl, WA3ZZU