[PPRAANet] RE: PPARES: RFI and Davis Wx stations

Wed, 23 Apr 2003 09:56:54 -0600

Ben,

OEM Electronics should have a good supply of shielded multi-wire cable. Be sure to connect the shield to (ideally) the shielded enclosure of the weather instrument. If the enclosure is not shielded, then it should be connected to the printed circuit board ground. The other end of the shielded cable should likewise be connected to the control box enclosure or PCB ground. Make sure the shield connections are physically short.

While you have the cable disconnected from the control box (assuming that's where the noise source is) do you still get the noise in your receiver? That would be a good test to see whether it's coming directly from the control box or whether it's the cable that's radiating.

One of the clamp-on ferrite cores may also help at the control box end of the shielded cable. Make sure it's clamped as close to the enclosure as possible.

Not being familiar with the Davis instrument, is it stickered for FCC Class B emissions? If it is, and assuming it meets the emission limits, you may just have to physically separate the unit from your receiver.

73, Ken (WA6TTY)

-------------------------------------------------------------
Ken Wyatt
DVU Hardware Test Center Manager
EPSG Product Regulations Representative
Agilent Technologies
Colorado Springs, CO
(719) 590-2852
[email protected]

-----Original Message-----
From: Benedict B. Cruise [mailto:[email protected]]
Sent: Wednesday, April 23, 2003 9:43 AM
To: ARES reflector; PPRAA reflector
Cc: [email protected]
Subject: PPARES: RFI and Davis Wx stations

Thanks to all that responded to my original e-mail asking for help on this
problem. I still have not solved the problem but I am working on it.  The
Radio Shack toroid coil choke, suggested by Davis,  did not do much good.

    Word to the wise,  Davis is not much interested in this problem in their
stations!

    Kit, KA0WUC suggested shielded cable from the junction box to the
monitor.  I am looking for the cable now.

73's  Ben, N0LNW

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