Neil Smith G4DBN

Nasty LEDs often radiate really well at 200MHz or so.  I had a batch that killed DAB radio and wiped out 2m completely.  I took all 16 back and swapped them for Philips versions which are at least 30dB quieter. Does enabling the LPF make any difference at all to the level of noise? It could be loud enough for the image of HF to be heard.  See if you can hear any change on a DAB or FM broadcast radio with the lights on.

I can hear the lights in a neighbour's house 300m away on 50MHz through to 144MHz.

Is there any structure to the noise?  Any peaks or tones?  Does the attenuator make any difference?  Any sign of the PK indicator showing?  Do you have filters with your DUO?  Any difference on different antennas?  How about on just a few feet of wire in the socket?

If it is the image issue, the LPF should fix it, but  not if the noise is getting into the radio via some other path.

Let us know how you get on.

The flickering TV doesn't sound good, must be some pickup somewhere.  What are you doing for a station earth?

Neil  G4DBN

On 12/11/2019 18:16, Thomas McQuiggan wrote:
Hi there. When I switch on the (12) LED downlighters in the lounge, I get horrible noise through the FDM DUO, but they don't effect my ICOM IC-7400 on the same antenna on the same frequency. Any ideas??

Also, a full licence friend came over and when transmitting QRO, the lights and TV flicker badly but not when he transmitted 100W on the ICOM!

Thanks de M7MCQ

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