Tag: Interference

Results of the VDSL interference survey

The EMC Committee would like to thank all 1,200 radio amateurs who took part in the VDSL RFI survey. The results have been analysed and were presented at the RSGB 2017 Convention. You can see a pdf of the PowerPoint presentation or watch the video of EMC Chair John Rogers, M0JAV presenting the findings at the […] Original Article

ARRL Reminds Amateurs to Keep Clear of Frequencies Designated for Puerto Rico-Caribbean Emergency Response

ARRL reminds Amateur Radio operators that emergency communications are taking place on and around 14.265, as well as other frequencies. Please avoid these frequencies whenever possible, to allow for emergency communications to transpire clearly and efficiently.

If you must be on the air in the vicinity of these frequencies, please allow emergency operators at least 2 or 3 KHz on each side. Thank…

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Improving Switch Mode PSUs for noise

I’ve never been into switch-mode power supplies . . .

But preumably the reason they radiate so much RF noise is because they chop the mains into a high-frequency square wave signal, that can then be transformed using a small transformer.

So I presume those that are quiet (in terms of RF hash) use inductors and capacitors to round off the edges of the square waves. (rather than just relying on RF filtering of the DC output, by which time it’s too late . . . as the hash seems to…

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UK VDSL interference survey extended

The RSGB EMC Committee has been investigating VDSL broadband interference on the HF amateur bands for three years now. To increase the amount of evidence available, the Committee set up a survey to collect current signal levels at the frequencies of VDSL band transitions. There are still lots of responses being received so the deadline […] Original Article

Not All “Intruders” on Ham Bands are Illegal — But a Lot of Them Are

The monthly newsletter of the International Amateur Radio Union Region 1 Monitoring Service (IARUMS) typically makes for some interesting reading. While the reports that come from more than two dozen contributors in Europe and Africa can be a bit visually dense, the content conveys the impression that that there are myriad intruders on the Amateur Radio bands. However, not all of them are illeg…

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