Hello, I just bought an external power supply for an old radio I'm using. The only problem is that it is generating a huge amount of noise on the AM and SW Radio bands I want to use it for... It seems to have some beads around the output but I don't know if it's ferrite or just a simple filter. The noise starts low when I plug the power in it and keeps disturbing all radio frequencies on the bands I listen to. Any ideas to get rid of this noise? Or building a DIY PSU for 24V 6A output using spare parts from old pc's etc? I think I just wasted my money once again on this piece of crap as it blocks all I want it to use it for..

 

Could be conducted line problem.

Start with a couple of turns on output and input side of brick. Same for
radio on line side.

https://www.mouser.com/ProductDetai...MIh6mAy9yC2wIVkMVkCh3CnABsEAQYBSABEgJeSvD_BwE


Regards, Dana.

 

As it's switch mode that is only to be expected. You need a linear supply - big, heavy (relatively) mains transformer, rectifier, smoothing and possibly a regulator. You can still buy linear supplies but they are becoming rarer and they are more expensive than their switch mode cousins.

 

I concur with @AlbertHall: you need to either buy or make a linear supply. I don't care how well they're filtered, switching supplies (like those in PCs) produce lots and lots of EMI (as well as high-frequency ripple) and don't play well with sensitive stuff like radio receivers or low-level analog circuitry.

 

I concur with @AlbertHall: you need to either buy or make a linear supply. I don't care how well they're filtered, switching supplies (like those in PCs) produce lots and lots of EMI (as well as high-frequency ripple) and don't play well with sensitive stuff like radio receivers or low-level analog circuitry.

This opinion depends on the supply. I have a number of high quality switching power supplies the serve me well in the ham shack. The Elecraft K-3 and KX-3 are arguably the most sensitive HF receivers on the planet. Excessive conducted and radiated noise may have been true once upon a time, but is no longer necessarily the case.

This one for example
http://www.duracomm.com/product/eh-30/

 

You could try danadak's suggestion, but it's likely that it will take more filtering (possibly internal) than that to suppress the noise sufficiently for your use.
Notice that it's designed for "notebook computers and digital electronic devices" which are generally insensitive to such noise.

Does the noise vary with the distance of the supply from the radio?