Noisy Guest Revisited

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

 

While no responses are necessary or expected because the message only
conveys info without asking a question, the subject is certainly on topic
since Guest supplies very popular but noisy battery chargers.

What's your beef with that?

 

W1ZR claims that winding as many turns as possible around an Amidon
FT-240-4-3 core on the AC side and a Pi filter comprising 0.01uF caps and 8
turns (all that fit) of 14Ga Marine duplex on the DC side, buth as close as
possible to the Guest, fixed the noise in his landlocked QTH. I haven't
tried it myself yet .... I'm waiting for you (c:

73, K3DWW