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Grounding is an Issue/Hardware Observations/Interference Generated Wind Readings

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  • Kevin
    I recently rebuilt the PC serving up WUHU data via WS-2315. I have the PC floating ground wise (I removed the grounding pin on the AC cord) I did this to solve
    Message 1 of 1 , Aug 12, 2009
      I recently rebuilt the PC serving up WUHU data via WS-2315. I have the PC floating ground wise (I removed the grounding pin on the AC cord) I did this to solve a ground loop issue between my home theater receiver and PC. The PC is effectively grounded to the home theater gear not the AC line. After I reconnected everything minus the coaxial digital connection to the home theater, I had arbitrary (high) wind readings. As soon as I connected the home theater system coax the problem disappeared. Thus in addition to shielding of the cable from sensors, or twisting of the phone cord, or installing ferrite chokes to eliminate this problem grounding also seems to be an issue. I had the same results using straight RS232 connection and also using a Belkin RS232 to USB adapter. I would have thought the adapter would have lifted the grounding problem but no. As far as I know the weather instruments are not grounded anywhere so I'm not sure why this is an issue. I now have 70 feet of flat phone cord twisted with ferrite chokes on both ends between the wind sensor and the temp hum unit, 30 feet from the rain sensor and 100 feet of round unshielded cable from the temp/hum unit to the station. Its working interference free. I made a new cable to go from the station to the PC as the cheap one supplied had a bad connection. It's just round four wire unshielded phone wire with male RJ11 one end and 9 pin D male on the other. I also replaced the wind sensor with a cupped variety and finally have good wind readings at low speeds. The supplied turbine sensor never worked right. The impeller just doesn't have enough leverage over the friction of the shaft to work at low speeds. I read NASA tested spray cooking oil as the best lubricant so after a year and a half when the turbine gunked up I sprayed some of that on and it brought it back to original but it still did not perform low speed. I can highly recommend the TX20 cupped sensor. Overall the system has been working great for several years. See www.kevinspage.com
      Thanks!
      ~Kevin.
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