I'm going to start this off by saying I'm very new to this and I don't really know a lot so any detailed information would be much appreciated.
I have just started using an SDR (a cheap RTL model) with my MacBook Pro laptop. The laptop itself is a 2012 and the power supply is a bit older, I bought neither new. I've discovered that while the computer is on battery power I get very little or no interference on 1-30 MHz bands. I will also note, I'm using a Ham It Up upconverter to get access to the HF bands.
When I plug the computer into its power adapter I get a ton of interference, so much so it makes it difficult to actually receive even local AM stations. When the computer is on battery, no such interference. I do have a travel-charger which is a lower wattage for the computer, and when I connect it there is an uptake in interference but it is manageable.
My question is, what can I do to the power supply to reduce its interference? I'm not sure if the interference is coming in to the system via the line or if the interference is coming in to the radio via the air. I'm not even sure if that makes sense, but I hope it does.
Again, any help would be appreciated. I don't have / want to sink a ton of money into this as a project, for right now I can take the easy way out and unplug the laptop from the wall outlet and play around for a 2-4 hours before plugging it back in again.
Thanks in advance.