I installed a RF choke and decoupling capacitors on the input and output of mine and it helped quite a bit. I also use a DC Boost Converter from Amazon.
I've got a cheapie $10 buck regulator off Amazon that generates some serious noise to my BitX, and I tried 2 different brands of mini DVM's (as a simple battery indicator) and both kicked off even more noise, but I also have an even cheaper
boost converter built into the case to get my finals up to 20V that is nearly silent - Only a slight quiet hiss can be heard.? It seems to be rather hit or miss.
