On Sat, 12 Nov 2011 20:54:02 -0000 "Doug Turnbull" <[email protected]> wrote: >...some use inverted L antennas of 160 feet >plus in length and > others like myself have them closer to a quarter wave
Doug, You had a great signal here in Miami the other night, so I think your antenna works well (enough). So don't rush out to lengthen your inverted L just yet :-)... But...some believe that a longer antenna will move the current maximum higher, away from the lossy ground. As others on this reflector have pointed out, when a buried, or on the ground, radial field is insufficiently dense to shield the antenna's H field from the ground, the resulting eddy currents through the (less then perfect) ground will result in losses. The less of the field is intercepted by the ground, the lower these losses. Hence the idea of moving the current maximum -- and thus the field maximum -- up. I have done some informal testing comparing a 1/4 wave vertical with an almost 1/2 wave vertical and found that the longer antenna put out a stronger signal. So there may be something to this theory... Of course, with an inverted L you do not want to move the current maximum into the horizontal section, so the antenna should not be too long. 73, George, AA7JV _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
