The Noise

 

Introduction

Pictures

Who: JH3VFI Masanori Yamane, JO3TND Taro Adachi, JH6NSS Syunichi  Ishimatsu, JP1QGO Hiroyuki Daihara, JL1GJE Kensuke Sawada, JH1BSJ
      "Jin" Hitoshi Shibayama, JA1NVF Katsumi Yoshinuma, AD6ZY Paul Gill
What: find the source of THE NOISE
Where: Yokosuka Research Park, Yokosuka, Japan
When: 2004-02-28
Why: we're just like the Grinch, WE HATE NOISE!
How: use portable radios to find the noise "hot spots", use a spectrum analyzer to show what frequencies the noise affects
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"Pachi" toroidal cores around coax and a closeup of an open core. Called "pachi" because of the sound made when closing them, they are much easier to use than non-opening cores.

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JL1GJE Sawada-san runs the radio while JH3VFI Yamane-san inspects a toroidal core. Note the blue Ethernet cable, which serves as a ground which is hopefully cleaner than the ground we'd been using previously (many thanks to YRP for helping us find the cleaner ground). The new ground comes up from the floor under the couch. (The thin wires in the Ethernet cable don't exactly fit the definition of "physically large for low conductivity", but it's much better than nothing.)

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JH1BSJ Shibayama-san and JA1NVF Yoshinuma-san use a portable radio to find noise "hot spots" up on the roof by the antenna.

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JP1QGO Daihara-san uses a portable radio to find noise "hot spots"

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JL1GJE Sawada-san in the jury-rigged "dark room" needed to view the output of the spectrum analyzer --- without the dark room the sun overwhelmed the display.

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JA1NVF Yoshinuma-san grounds a jury-rigged shield while JH6NSS Ishimatsu-san holds an antenna connected to the spectrum analyzer. Perhaps motor noise is getting into the power line?

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View of the noise (and various cell phone frequencies) on the spectrum analyzer --- the amateur radio HF bands are pretty well buried in noise.

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Putting toroidal cores on the coax lines.