[CQ-Contest] LED Lighting RFI

Thu Oct 19 16:19:30 EDT 2017

Hi Charley,

Take the time to look up the GM3SEK lecture at the RSGB  Convention - Clean Up Your Shack

https://www.youtube.com/watch?v=LSL1h6MJbaI

A very detailed presentation of the causes of the RFI you are experiencing and real world solutions 

A quick short version - 

Ensure the shack grounding is done well

Use a single feed to power the shack and filter the mains 

Use common mode chokes on all antenna's coming into the shack - sometimes needs more than one.

These days the switch modes etc are ruining the hobby - and sadly the worse places seem to be in  the exotic DX locations like Asia, Africa and South America.

This presentation is particularly good explaining your problem and how to fix it. 

73 

Trent VK4TS

-----Original Message-----
From: CQ-Contest [mailto:cq-contest-bounces at contesting.com] On Behalf Of Charles Harpole
Sent: Thursday, 19 October 2017 12:04 PM
To: Mike Ritz; Svante Nordenstrom; Tony Waltham
Cc: Contest List
Subject: Re: [CQ-Contest] LED Lighting RFI

Advice re noise sources........
 What should I look for when I have a noise starts at 6pm local and runs for about hour with FAT PICKET FENCE display at ten over, no pauses, and then breaks up into less loud and sharp and narrow picket fence on the
display of it.    Turning antenna shows strong sig from NW to
NE....definitely North.

Covers all bands.  6pm is dusk here.

Pse what kind of devices should I look for?   Is there a Web site with
noise samples?

Tnx, 73, Charly

On Wed, Oct 18, 2017 at 9:41 PM, Mike Ritz <w7vo at comcast.net> wrote:

> I just bought a 70's vintage nice quality transistor AM radio at at 
> thrift store, and have been taking it around my house to listen for noise.
> Surprisingly, the LED bulbs I have in all my lighting fixtures have 
> been quiet. My DirecTV box is VERY noisy, as is my Accurite weather 
> station. My
> 2009 vintage Samsung LED TV also emits a lot of hash, but can only be 
> heard when I put the radio right up to the television. Fortunately for 
> me, my shack is in my metal shop, (on a separate power feed), but of 
> course, my antennas are not. Now that I have this "tool" I am going to 
> take a hard look a every piece of electronic stuff I own and evaluate the noise levels.
>
> 73;
> Mike
> W7VO
>
> ----- Original Message -----
>
> From: wigi at kl0r.com
> To: "K9MA" <k9ma at sdellington.us>
> Cc: cq-contest at contesting.com
> Sent: Tuesday, October 17, 2017 9:56:16 PM
> Subject: Re: [CQ-Contest] LED Lighting RFI
>
> Thanks for the post, Scott... We have a pernicious noise problem from 
> power supplies at KL7RA... from the DirectTV boxes. We can take them 
> offline, but it would prevent ops from watching "The Young and The 
> Restless" reruns on the Soaps channel. I am curious if there are any 
> suggestions for quiet switching supplies for the random home electronics??
>
> Wigi
>
>
> -----Original Message-----
> From: CQ-Contest [mailto:cq-contest-bounces at contesting.com] On Behalf 
> Of K9MA
> Sent: Friday, October 13, 2017 11:38 AM
> To: CQ Contest <cq-contest at contesting.com>
> Subject: [CQ-Contest] LED Lighting RFI
>
> Last winter, I tracked down some bad RFI to a neighbor's LED lighting 
> system. Replacing the power supply completely eliminated the interference.
> I just bought a similar one for my own home and tested it for RFI, 
> finding none at all from 160 through 20 meters. Antennas were less 
> than 25 meters from the power supply and lights. I have plenty of 
> other noise in this urban location, so there might be noticeable RFI 
> in a quieter location, but this power supply is certainly a lot 
> quieter than many of the others in the neighborhood.
>
> I can recommend the Armacost power supplies manufactured by MOX 
> Lighting, models MD24W12VA and MD45W12VA. The 60 W version from LTF 
> Technologies was the bad one, but Armacost told me they were dropping 
> that vendor, and the MD60W12VA Armacost sells now appears to be made 
> by MOX, though I haven't tested it. By all means, stay away from 
> anything manufactured by LTF Technologies.
>
> It appears it really IS possible to build low-cost switching supplies 
> that don't generate enormous amounts of RFI.
>
> 73,
>
> Scott K9MA
>
> --
> Scott K9MA
>
> k9ma at sdellington.us
>
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--
Charly, HS0ZCW
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