I'm working on tracking down some 2m repeater interference, and I have identified that the offending signal is a spur transmission on a commercial pager service (that lands right on our repeater input frequency).

How would I identify regulations that the commercial transmitter should be observing, to verify that their equipment is operating properly, or what are the regulations for a commercial transmitter? (For the purposes of this question, I'm located in the USA)

To measure the spur signal, I plan on using a spectrum analyzer to measure the relative magnitude from the fundamental frequency to the spur. I will use an antenna to observe the signal from off-site. Are there potential issues with this method?

I'm interested in this approach out of curiosity on whether this is a viable option, not because it is currently necessary.

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    $\begingroup$ You might start by finding the station in the ULS and contacting the licensee directly, before filing a complaint with the FCC. It could be that they aren't breaking any regulations, but if they are friendly they might help anyway. If they aren't friendly, then you can feel better about making trouble for them with the FCC. $\endgroup$ – Phil Frost - W8II Apr 20 '14 at 12:53
  • $\begingroup$ @PhilFrost We're working on that, and I suspect that a neighborly action from the offending site will be what fixes things. I am doubtful that they are out of compliance, but I would like to be certain (and know for the future). $\endgroup$ – W5VO Apr 20 '14 at 16:10
  • $\begingroup$ @PhilFrost Ultimately, we did contact the license holder and the offending station was very responsive to the issue and were able to fix their transmitter. $\endgroup$ – W5VO May 2 '14 at 0:20

Your method of measuring the spur signal is perfectly acceptable, and perhaps the best method for this scenario.

Search the FCC database for the transmitter owner that you suspect is on the frequency that's causing the problem. Contact them given the information within the database. In my experience, groups are responsive to requests to clear up any superfluous signals.

If they respond malignantly to your request, it's time to contact the FCC.

Keep in mind that the spur could be a mixing problem with more than one signal involved. For example, 152 MHz and 159 MHz could result in a 145 MHz spurious signal.


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