Hi Pete,
Unfortunately you've installed your BOG so that the power line is in the near field of your antenna. Antennas fully develop their directive patterns in the far field, not in the near field. Large antennas develop their directivity far from the antenna, small antennas develop their directivity much closer to the antenna. Very large arrays such as phased 1000 foot Beverages and 350 foot diameter 8 circle arrays develop their directivity 1000 feet or more from the antenna. Small antennas such as "magnetic" loops, K9AY and VE3DO loops develop their directivity less than 100 feet from the antenna. In your situation the best choice is a small antenna such as a VE3DO loop as far from the power line as possible. A small magnetic loop is capable of completely nulling a single RFI source but it has much lower sensitivity that a VE3DO loop. Talk to PVRC member N3HEE about his results with a small magnetic loop in his challenging RFI environment on a small lot. 73 Frank W3LPL ----- Original Message ----- From: "N4ZR" <[email protected]> To: "topband reflector" <[email protected]> Sent: Friday, February 8, 2019 4:31:29 PM Subject: Topband: BOG near noisy powerline on 160 Recently I put down a 220' BOG, using the KD9SV hardware, including the preamp. Because of my yard's layout, the forward end of the BOG fell within about 20 feet of what the power company has identified (but not fixed yet), a noisy line with a number of broken insulators. I came in to listen to the antenna, and was surprised to note that my noise (mostly from the powerline, by ear) is worse on the BOG than on my jury-rigged sloper transmit antenna. It is much (maybe 20 dB) worse in the direction toward the power line than in the opposite. While I take this as encouraging evidence that the BOG has some directivity, I don't think I'm even hearing any atmospheric noise that may be present, because of the power line. So now I'm wondering, is the BOG in this position worth keeping, even assuming that I can eventually get the power company to fix the line. Or should I look at another type of receiving antenna, such as a K9AY loop or SAL, which can be placed much farther from the power line? -- 73, Pete N4ZR Check out the Reverse Beacon Network at <http://reversebeacon.net>, now spotting RTTY activity worldwide. For spots, please use your favorite "retail" DX cluster. _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
