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Another probably stupid question....about interference

iiiquaziii

Member
Jan 17, 2014
57
17
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Buffalo NY
So I have a laptop set up in the radio room, I plan to use with an interface box for CW get, CW Type, and SSTV. The power brick for it throws off all kinds of noise. I jump from having 0 S-units of static up to like 7 units as soon as I plug the charger brick for the laptop in. Its bad. People can hear it when I transmit too.

Is there anything I can do, besides putting a filter on the radio, or replacing the charger? Can I shield it somehow? The thought of wrapping it in tin foil, or putting it into a metal box came to mind.....I haven't experimented yet though....
 

I've tried plugging it into different outlets in the radio room, and moving it a little father from the radio, but space is at a premium in here, and it made no difference.
 
I've noticed the same thing with my HP laptop charger, it's my 'bench computer" also, I literally unplug the charger and run it on battery for when I need to interface it to a radio, the "hash n trash" was too much, and likewise people heard it in my transmit audio.

I am interested in a solution, I don't know but I think if I build a "Lead Coffin" (box) for it to rest in, maybe that will help some!
 
I am going to try wrapping the whole thing in foil, including the cord, and grounding the foil as soon as I get some more foil....lol. Probably won't do squat.
 
Well, I just did an experiment, and wrapped the whole brick tightly with 2 layers of foil....and the cords..........I then tightly rubber banded a wire around the foil with several wraps around it, and ran the wire into to my ground lugs. It helped....a LOT. It cut the problem back from like 7 or 8 S-units of static, down to like 2-3. It didn't eliminate it, but it cut out a lot. I'm now wondering if I come up with a better way to shield this thing if it will solve the problem entirely.......
 
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Maybe next try some of those snap-on ferrite beads, or coil the wires? I don't know if that would help with emissions, I think you are on the right path, maybe I can make a shield for my laptop charger; i'll have to try it out!
 
I think you've about got it covered. I'd go ahead and try the torroids anyway. GOOD! Now come over and cure my problems??
 
my kenwood ts 2000 is now making a tick tick sound. but only on the antenna. put it on the dummy load. the sound goes away.
any ideas.
thanks.
 
Disconnect the coax from the radio and see if the sound is still there. If it is, I'd guess you have voltage building up at the antenna because of weather.
 
Yo iiiquaziii: Yeah good call wrapping the charger with foil, that's a good trouble shooting call, good going. So now you know the charger is radiating EMI or RFI Interference.

Many of the Chinese made voltage regulators / Batter Chargers are cheaply designed and built for mass production and no design or assembly considerations for EMI or RFI Interference, and there is no FCC standard for interference levels for some of these units.

Beetle said to try another manufacture of battery charger, good call. Worth a try.

Jay in the Great Mojave Desert
 
found the problem. after much trouble shooting.
i decided to swap power supplies noise gone. it was a megawatt ps gone bad. lucky for me i have 3 of them.
 

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