[RFI] update <was> 40m (and other) noise

K1TTT K1TTT at ARRL.NET
Sat Apr 11 04:16:28 PDT 2009


A laptop charger is a good suspect.  Had one that someone brought here
during a contest that made all sorts of noise.


David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
 

> -----Original Message-----
> From: Sam Morgan [mailto:ka5oai at gmail.com]
> Sent: Saturday, April 11, 2009 01:39
> To: rfi at contesting.com
> Subject: [RFI] update <was> 40m (and other) noise
> 
> neighbor came home this afternoon and the noise changed
> it disappeared from 40m,
> 
> and changed from light noise on 30m (compared to 40m)
> to very distinct noise humps on 30m
> 
> then about an hour or 2 later,
> it changed back to wiping out 40m and light noise on 30m
> 
> I had a brief talk with the neighbor,
> but it was an inopportune time, just getting out of bath, oops..
> so I'm going to have to try again another time/day
> 
> but in the brief chat, I did find out,
> no plasma tv,
> their computer is a laptop,
> he did say it's power supply had been plugged in all day,
> while the laptop was with them
> 
> I'm making a couple of wild guesses here and would like to have ya'll's
> feedback
> 
> I'm wondering if perhaps the laptops power supply was plugged in
> and unloaded all day, no battery or laptop on it to charge,
> then when they came home it was plugged in and the laptop turned on,
> so power supply was under load and the noise changed,
> then they turned it off and the change back to the original noise?
> 
> Another wild guess was if it was a cell phone charger that was unloaded
> during
> the day and then they placed the phone(s) in the power supply cradle when
> they
> got home, so under load....., then after fully charged, the change back to
> the
> original noise.
> 
> I don't have either a cell or a laptop, so I have no clue how long they
> might
> charge, or otherwise work...
> 
> I really couldn't pursue the questions when I spoke so I'll have to do it
> again
> at another time.
> 
> If it were either one of these appliances, where would I place a snapon
> toroid.
> Near the wall wart end or the appliance end.
> 
> Sorry for rambling, just trying to be prepared for my next encounter....
> 
> --
> GB & 73
> KA5OAI
> Sam Morgan
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