{"id":4699,"date":"2012-03-16T14:22:56","date_gmt":"2012-03-16T18:22:56","guid":{"rendered":"http:\/\/www.engineeringradio.us\/blog\/?p=4699"},"modified":"2023-04-29T11:07:21","modified_gmt":"2023-04-29T15:07:21","slug":"lightning-season-2","status":"publish","type":"post","link":"https:\/\/www.engineeringradio.us\/blog\/2012\/03\/lightning-season-2\/","title":{"rendered":"Lightning season"},"content":{"rendered":"\n

Here in the northeast, there are seasonal variations in the types of weather phenomena encountered.\u00a0 Blizzards in the winter, severe thunderstorms, and the occasional tornado in the summer, at least that is the way it normally happens.\u00a0 This year, we have already had two thunderstorms and a stretch of unusually warm weather.\u00a0 My highly advanced personal weather prognostication technique consists of looking at trends, and the trend thus far this year is warmer with more storms.<\/p>\n\n\n\n

\"Weather<\/a>
Weather Radar, thunderstorm line<\/figcaption><\/figure>\n\n\n\n

When the weather RADAR looks like this, it is too late.<\/p>\n\n\n\n

To that end, it is time to go around and check all of the grounding and lightning suppression methods at various transmitter sites and studios.\u00a0 I would rather spend a few minutes extra now than get called out in the middle of the night for an off-air emergency related to a lightning strike.<\/p>\n\n\n\n

Proper grounding of all equipment, RF cables, and electrical service entrances is the minimum standard for transmitter sites.\u00a0 Proper grounding means a common point grounding system connected to one<\/em> ground potential.<\/p>\n\n\n\n

To that end, all coaxial cables that enter the building need to have their outer shields bonded to the site grounding system at the base of the tower and the entrance of the building.\u00a0 With an FM station where the antenna is mounted at the top of a tall tower, the coaxial cable outer jacket acts as an insulator along the length of the tower.\u00a0 A lightning strike on the tower will induce a very high potential on the outer conductor of an ungrounded transmission line.\u00a0 After entering the building, the lightning surge will find the next path to ground, which will likely be a coax switch or the transmitter cabinet.\u00a0 Neither of those two outcomes is desired.<\/p>\n\n\n\n

Thus, it was time to ground the transmission lines at WRKI, the FM transmitter we moved last January.<\/p>\n\n\n\n

\"3<\/a>
3 inch coaxial cable grounding kit<\/figcaption><\/figure>\n\n\n\n

Fortunately, Andrew, Cablewave, Dielectric, and others make grounding kits for various size coaxial cables. They are very easy to apply and make a solid connection between the outer conductor and the site ground.<\/p>\n\n\n\n

\"3<\/a>
3 inch coaxial cable grounding kit<\/figcaption><\/figure>\n\n\n\n

The kit contains a copper band bonded to a ground wire, stainless steel clamp, waterproofing, tape, and a pair of bolts.<\/p>\n\n\n\n

\"3<\/a>
3 inch coaxial cable properly grounded<\/figcaption><\/figure>\n\n\n\n

The concept of transmitter site grounding is pretty simple and inexpensive to implement.\u00a0 Thus, it is surprising to me how many transmitter sites, especially older sites, do not have adequate grounding.\u00a0 That is an accident waiting to happen.<\/p>\n\n\n\n

For more on transmitter site grounding, check Nautel’s publication (.pdf) “Recommendations for Transmitter Site Preparation<\/a>.”<\/p>\n","protected":false},"excerpt":{"rendered":"

Here in the northeast, there are seasonal variations in the types of weather phenomena encountered.\u00a0 Blizzards in the winter, severe thunderstorms, and the occasional tornado in the summer, at least that is the way it normally happens.\u00a0 This year, we have already had two thunderstorms and a stretch of unusually warm weather.\u00a0 My highly advanced … Continue reading Lightning season<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21,4],"tags":[218,5],"class_list":["post-4699","post","type-post","status-publish","format-standard","hentry","category-tales-of-disaster","category-tech-stuff","tag-grounding","tag-lightning"],"_links":{"self":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/4699","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/comments?post=4699"}],"version-history":[{"count":8,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/4699\/revisions"}],"predecessor-version":[{"id":11632,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/4699\/revisions\/11632"}],"wp:attachment":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/media?parent=4699"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/categories?post=4699"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/tags?post=4699"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}