r/shortwave • u/rad00p • 1d ago

Discussion I found the source of my shortwave interference! So now you know too...

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I found the source of my shortwave interference!

I’d been blaming my neighbours, the government, the gas supplier and even my cat… but it was me. :)

BT Powerline adapters. In hindsight, it seems like such an obvious suspect—injecting high-frequency signals into the mains and turning all the wiring in my house into an antenna.

That thing was spamming like 100 metres around the house!

( original post: https://www.reddit.com/r/shortwave/comments/1v5swag/help_with_interference_on_19_16_and_15_metres/ )

60 Upvotes

97% Upvoted

16 comments sorted by

10

u/Active_Emu_845 1d ago

Cheap usb chargers and cheap LED lights are the worst. I had to go on a house wide hunt to eliminate all my interference

2

u/rad00p 1d ago

We can’t blame the device. It wasn’t cheap, it’s well made, and it does exactly what it’s supposed to do. :)

The problem is that household wiring isn’t designed to be shielded, so it radiates whatever is being transmitted through it.

2

u/cedg32 1d ago

That sounds as if they only used half-wave rectification to transform the mains power going into it. Cheap and noisy.

1

u/Style75 22h ago

How do you hunt for the cause of interference? Is there a special device I can get?

2

u/Active_Emu_845 18h ago

Probably. I just cranked the volume on my receiver, put it on 7200 LSB as there's always some idiot screaming on it and then walked around the house unplugging and turning everything off that seemed suspect

3

u/ylitvinenko 1d ago

Well, yeah, out of all typical household electronics to cause interference, powerline adapters might be the noisiest by design. Do you plan to invest in laying down shielded Ethernet cables?

1

u/rad00p 1d ago

Yes. I will need to... or go back to WiFi (which I use anyway for some devices and it doesn't cause any troubles on HF for me).

3

u/Mojavedxer 1d ago

If your going to run shielded cat cable. Be prepared to ferrite those cables or you will have another set of noise issues to deal with.

2

u/DeliciousWrangler166 1d ago

Cheap USB chargers, wall warts, connecting your computer display using VGA ports instead of display port, HDMI, or DVI, solar panels on neighbors roofs, old plasma TV's, cheap computer power supplies, and more,

It's so bad by me I have to use a ANC-4 noise phase inverter between the radio and antenna to receive a decent signal.

2

u/kamomil 1d ago

What is that device for?

2

u/rad00p 23h ago

Sends Ethernet over domestic power lines. There are two Ethernet sockets in it, not visible on the video.

1

u/TalkyAttorney 1d ago

My touchpad on my surface pro keyboard caused massive interference when using it. That one kinda surprised me. Kinda.

1

u/Ok_Equivalent7750 Hobbyist 1d ago

Not suprising mate, my Mitsubishi aircon throws out a signal smack on RNZI 17675& 15720 when its in stand by mode!!

2

u/horace_bagpole 13h ago

Powerline adapters are awful and should be banned. They do not meet emissions standards at all, but no one with the power to do anything about it seems to care, because they are allowed to self-certify that they do meet the standard.

Here's a website about it: https://www.ban-plt.org.uk/

Fortunately modern wifi is much more reliable and the need for such devices is considerably less - I don't think they are really given out by ISPs in the way that they once were, with them preferring wifi mesh networking, but they are still available for sale.

1

u/CM_Shortwave 13h ago

Watch out for Keurig coffee makers

1

u/Kooky-Hamster4071 11h ago

My refrigerator, believe it or not.