From: Jon Clarke Date: 19 May 2000 12:30:47 Subject: [IGEXMail-0765] NPLB and NPLC interruption MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="---- =_NextPart_000_01BFC185.7AC364A0" Reply-To: IGEX Mail Sender: IGEXMail-owner@ensg.ign.fr Precedence: list ****************************************************************************** IGEXMail 19-May-2000 12:30:47 Message No 0765 ****************************************************************************** Author: Jon Clarke Subject: NPLB and NPLC interruption ------ =_NextPart_000_01BFC185.7AC364A0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Dear Colleagues,=20 during a lightning storm yesterday (about 16:00 UT, 18 May 2000) the = 1pps reference for our Ashtech NPLB and R100 NPLC jumped (to our = frustration...).=20 It's not clear to us why this should have happened, as all our 1pps and = 5MHz distribution equipment is now on uninterruptible power supplies, = ruling out a power interruption. There were no lightning strikes nearer = than several kilometres away, ruling out direct interference. There is a = 200m cable taking a 5MHz between our two buildings, and it lies next to = other cables. There may have been interference due to this, perhaps a = large transient on a nearby cable due to a strike on electrical = equipment elsewhere. To reduce any effects, we have now put an RF = transformer on the 5MHz supply cable to avoid any ground current flow = into our distribution equipment.=20 Today (11:00 UT, 19 May 2000) we have reset the reference and equipment. = Regards,=20 Jon=20 ------------------------------------------------------------------------ Mr Jon Clarke Time and Frequency Section, jon.clarke@npl.co.uk Centre for Electromagnetic and Time Metrology, tel: +44 (0) 20 8943 6548 National Physical Laboratory, fax: +44 (0) 20 8943 6529 Queens Road, Teddington, TW11 0LW, U.K. ------------------------------------------------------------------------ ------ =_NextPart_000_01BFC185.7AC364A0 Content-Type: application/ms-tnef; name="xsmtp-tmp-1.tnef" Content-Transfer-Encoding: base64 eJ8+IhYKAQaQCAAEAAAAAAABAAEAAQeQBgAIAAAA5AQAAAAAAADoAAEIgAcAGAAAAElQTS5NaWNy b3NvZnQgTWFpbC5Ob3RlADEIAQSQBgC0AgAAAwAAAAwAAAADAAAwBAAAAAsADw4AAAAAAgH/DwEA AAAcAAAAAAAAANl0fUIochHPqC0AQDMkuqcCBgEAiQEAAB4AAjABAAAABQAAAFNNVFAAAAAAHgAD MAEAAAAcAAAAR0VUVEBDTE9DS0RFVi5VU05PLk5BVlkuTUlMAAMAFQwBAAAAAwD+DwYAAAAeAAEw AQAAAAoAAABHRVRUX2xpc3QAAAACAQswAQAAACEAAABTTVRQOkdFVFRAQ0xPQ0tERVYuVVNOTy5O QVZZLk1JTAAAAAADAAA5AAAAAAsAQDoBAAAAAgH2DwEAAAAEAAAAAAAABAwAAAADAAAwBQAAAAsA Dw4AAAAAAgH/DwEAAAAcAAAAAAAAANl0fUIochHPqC0AQDMkuqcCBgEAkwAAAB4AAjABAAAABQAA AFNNVFAAAAAAHgADMAEAAAAVAAAAaWdleG1haWxAZW5zZy5pZ24uZnIAAAAAAwAVDAEAAAADAP4P BgAAAB4AATABAAAACQAAAElnZXhNYWlsAAAAAAIBCzABAAAAGgAAAFNNVFA6SUdFWE1BSUxARU5T Ry5JR04uRlIAAAADAAA5AAAAAAsAQDoBAAAAAgH2DwEAAAAEAAAAAAAABQwAAAADAAAwBgAAAAsA Dw4AAAAAAgH/DwEAAAAcAAAAAAAAANl0fUIochHPqC0AQDMkuqcCBgEANQAAAB4AAjABAAAABQAA AFNNVFAAAAAAHgADMAEAAAAOAAAAcGJ3QG5wbC5jby51awAAAAMAFQwCAAAAAwD+DwYAAAAeAAEw AQAAABEAAABXaGliYmVybGV5X1BldGVyAAAAAAIBCzABAAAAEwAAAFNNVFA6UEJXQE5QTC5DTy5V SwAAAwAAOQAAAAALAEA6AQAAAAIB9g8BAAAABAAAAAAAAAboYAEEgAEAGwAAAE5QTEIgYW5kIE5Q TEMgaW50ZXJydXB0aW9uAB8JAQWAAwAOAAAA0AcFABMACwAdABQABQAwAQEggAMADgAAANAHBQAT AAsAHQAUAAUAMAEBCYABACEAAAAxMTNEODg5QjY5MkRENDExOUNFMDAwQzA0Rjk1QUFENwAsBwED kAYAkAAAAAoAAAALACMAAAAAAAMAJgAAAAAACwApAAAAAABAADkAoG7yF33BvwEeAB4MAQAAAAUA AABTTVRQAAAAAB4AHwwBAAAAFQAAAGpvbi5jbGFya2VAbnBsLmNvLnVrAAAAAEAABzCA8HwXfcG/ AUAACDCgbvIXfcG/AR4APQABAAAAAQAAAAAAAAADAA00/TcAAG0Z ------ =_NextPart_000_01BFC185.7AC364A0--