| Przeciwwagi zakopane w ziemi z czego je wykonać? |
| Do poczytania: https://rudys.typepad.com/files/chapter-5-.pdf I cytat z Lowband Dxing: 2.1.6. Depth of buried radials C. J. Michaels, W7XC (Silent Key), calculated the depth of penetration of RF current in different types of ground. He defined the depth of penetration as the depth at which the current density is 37% of what it is at the surface. On 80 meters he calculated a depth of penetration of 1.5 meters for very good ground. For very poor ground the depth reaches 12 meters! From the point of view of I2R loss, you can bury the radials “deep” without any ill effects. However, from nearfield screening effect point of view, we need to have the radial system above the lossy material. Bob Leo, W7LR, in Ref 808 reports that burying the radials a few inches below the surface does not detract from their performance. Al Christman, K3LC (ex KB8I), confirmed this when modeling his elevated radial systems using NEC-4.1. He found a difference of only hundredths of a dB between burying radials at 5 cm or 15 cm. I would not bury them much deeper though. The sound rule here is “the closer to the surface, the better.” |