ARRL

W1MG

Joined: Sat, Apr 4th 1998, 00:00 Total Topics: 0 Roles: N/A
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Latest Topics

Topic Created Posts Views Last Activity
T8 Lamps Sep 20th 2011, 14:56 4 1,917 on 23/9/11
Part 15 and Plasma Televisions Sep 14th 2011, 15:13 2 973 on 14/9/11
Common-Mode Interference from Cable System Sep 13th 2011, 15:13 2 1,082 on 13/9/11
RFI from HVAC Systems Sep 1st 2011, 19:08 2 937 on 1/9/11
RFI from Plasma TV Sep 1st 2011, 17:20 3 1,877 on 13/9/11
Alignment of Vintage Shortwave Receiver - Pilot T-511 Aug 3rd 2011, 13:43 7 1,775 on 5/2/13

Latest Posts

Topic Author Posted On
Grid Tie Pv INVERTER RFI concern K7YDL on 18/1/13
A friend has an SMA inverter and it's proven to be remarkably quiet. I forget the model number, but he has had no issues with it.
LED lamps and interferance n1naz on 30/5/12
From what I've seen so far, there can be a wide range of conducted emissions from LED bulbs, depending on model and manufacturer. I plan on testing a number of them in the near future.
30 meters QRN; 20, 40 quiet? K2ADK on 23/5/12
If the noise rolls off dramatically with frequency, one possibility might be a local RFI source. Walking around your neighborhood with a battery powered shortwave receiver might verify this possibility. Antenna resonances can also cause noise to peak at some frequencies.
Broad Band Interference AC0XU on 5/1/12
Just as an FYI, if the noise is caused by an arcing source, a bad doorbell transformer can cycle on and off. You should, however, be able to hear it in the AM broadcast band and well into the VHF spectrum, especially at close range. Be sure to use the AM mode when listening at VHF. It will also not exhibit any discernable pattern as you tune across the spectrum, such as a regular and repeating pattern of peaks and nulls.
75 Meter RFI Problems W6LJK on 28/12/11
This sounds like it might be a consumer device of some sort. Most likely it is located either in your home or a nearby residence. Typically, based on the signal levels that you report, the source will be within a couple hundred feet of your antenna.

Note: Because the noise varies with intensity as you tune across the 80 meter band, it is unlikely to be power line noise. Your power company is therefore not responsible for either finding or fixing the noise.

The first thing I would do is turn off the main breaker to your residence while listening to the noise with a battery powered radio. If the noise goes away, you can further isolate the source by hitting the individual breakers. Once you know the circuit, try removing devices on that circuit to find the culprit.

If the noise source is not in your house, it is likely in a nearby residence. Often times, the source is in an adjacent residence or on the same power transformer secondary system as the complainant. You can use this procedure on the RFI Services Web site to find the source: www.rfiservices.com/residence.htm

Additional locating information can be found in the ARRL RFI Book and the 2012 ARRL Handbook.

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