{"id":183,"date":"2013-06-04T21:24:06","date_gmt":"2013-06-05T02:24:06","guid":{"rendered":"http:\/\/swaziland2013.mcguireclan.org\/?p=183"},"modified":"2014-06-01T13:32:27","modified_gmt":"2014-06-01T18:32:27","slug":"20130604-tuesday","status":"publish","type":"post","link":"https:\/\/mcguirereport.mcguireclan.org\/?p=183","title":{"rendered":"2013\/06\/04 — Tuesday"},"content":{"rendered":"

First thing this morning, I noticed that Transmitter 2 (TX2) efficiency was back to normal, but no reason could be found!\u00a0 One of the ways of comparing the efficiency of like transmitters is to check their cooling water temperatures.\u00a0 They should be the same.\u00a0 Using a hand-held digital thermometer, I compared all three 100,000 watt transmitters.\u00a0 TX1 & TX2 readings were comparable and similar to their computer readouts, but TX3 read was about 15 degrees higher than its computer reading, which was comparable to the other two transmitters!\u00a0 When TX3 was shut off, the hand-held thermometer instantly returned to a ‘normal’ reading!!\u00a0 TX3 had been on 9500kHz.\u00a0 After it was retuned to 7315kHz, the reading was normal.\u00a0 This confirmed that the hand-held electronic thermometer is sensitive to certain RF frequencies, which can cause erroneous readings.<\/p>\n

\"The<\/a>

The copper ring shown here is the same as the ones used on the feedline<\/p><\/div>\n

We made some adjustments to the feedline to Antenna 6 to see if the RF unbalance, when it is used on TX3, can be improved.\u00a0 The 300 ohm feedline consists of two conductors.\u00a0 Each conductor is made up of six wires spaced equally by 2 inch diameter rings (like the antenna element in the photo).\u00a0 On one of the feedline spans, the two top wires of the six were sagging, so we fabricated and added another ring, with clamps, to correct the sagging.\u00a0 When this was tested, there was no obvious improvement in the RF unbalance.\u00a0 We noticed that another span had two bottom wires of the six that were sagging.\u00a0 We cut two pieces of PVC pipe to temporarily pull these two lower wires into position\u00a0 Again, there was no noticeable improvement in VSWR or RF unbalance.<\/p>\n

In the afternoon, it was decided to test TX3 on Antenna 6 on 7300kHz at full power with modulation and have observers under the antenna to pinpoint any arcing problems.\u00a0 After about 30 minutes we heard minor arcing and Graham spotted its exact location.\u00a0 This arcing was not enough to trip the transmitter off, but if left to continue, it could possibly flare up to a much bigger arc due to heating and ionization of the air at this high voltage point.\u00a0 This may be what has been happening in the evening to cause the transmitter to occasionally trip off due to RF unbalance.\u00a0 At about 2:45pm it was decided to quickly let the antenna down and investigate.\u00a0 We found that the arcing was between the corona ring and where it was attached to the element.\u00a0 The bolt was not making a very tight connection.\u00a0 The connection was taken apart and a file was used to clean up the surfaces.\u00a0 The corona ring was then bolted more tightly onto its radiating element.\u00a0 Everything was put back together and the antenna raised in record time — before 3:30pm.\u00a0 We just had time to bring up the transmitter and test the antenna before evening broadcasts began.\u00a0 I listened to the broadcast in the evening and heard no dropouts at all.\u00a0 Will have to verify this by reviewing the logs when we get back to the site on Thursday.<\/p>\n

It was a really full day!!<\/p>\n","protected":false},"excerpt":{"rendered":"

First thing this morning, I noticed that Transmitter 2 (TX2) efficiency was back to normal, but no reason could be found!\u00a0 One of the ways of comparing the efficiency of like transmitters is to check their cooling water temperatures.\u00a0 They should be the same.\u00a0 Using a hand-held digital thermometer, I compared all three 100,000 watt […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_s2mail":"yes","footnotes":""},"categories":[5],"tags":[11,12],"class_list":["post-183","post","type-post","status-publish","format-standard","hentry","category-swaziland-2013","tag-11","tag-swaziland"],"_links":{"self":[{"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/posts\/183","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=183"}],"version-history":[{"count":1,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/posts\/183\/revisions"}],"predecessor-version":[{"id":690,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=\/wp\/v2\/posts\/183\/revisions\/690"}],"wp:attachment":[{"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=183"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=183"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mcguirereport.mcguireclan.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=183"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}