Writing in the December and February issues of QST, W1ZR describes using a
Guest charger as part of the "UPS" for his ham shack. He found that a choke
wound around an Amadon FT-240-4-3 core close to the Guest on the AC side
plus a "brute force" "Pi" filter composed of 0.01uF capacitors (RS272-131)
and 8 turns of 14Ga marine duplex cable on a Amadon FT-240-61 core beat the
noise down to 60dB. UMMV

73, K3DWW