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Old May 19th 08, 04:06 PM posted to rec.radio.amateur.equipment
Priz Priz is offline
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First recorded activity by RadioBanter: Nov 2007
Posts: 5
Default Laptop power supply noise getting transmitted

I'm running a Dell Latitude 2.8GHZ Laptop with 256MB RAM and Windows
XP PRO. My rig is a Kenwood TS-140S.

I purchased a Buxcomm Rascal interface to connect the laptop sound
card to the rig so I could try PSK31. Since the interface has a
serial connection, I use a USB to Serial interface in order to connect
it to the PC. It's connected to the rig via 13 pin DIN connection on
the back, with audio in/out through the headphone/MIC connectors on
the laptop.

Here's the problem. When I transmit, there's alot of noise being
transmitted which I think comes from the laptop power supply. I came
to that conclusion because when I run the laptop on batteries, the
noise isn't there. In fact, if I boot down the laptop and leave it
plugged into an outlet, if I connect the serial connector from the
interface to the USB/Serial adapter connected to the laptop and push
either the Send or the PTT on the microphone, that noise is
transmitted. I can tell by the way the ALC meter is moving. It's
like the noise is being transmitted into the rig via the cable which
connects the rig to the interface. This didn't happen the first day I
used the interface, but it started happening the day after.

I'm interested in ideas of what could be causing this and possible
remedies. All help is appreciated.

Thanks.

Priz