Having a strong high angle lobe can be a benefit when seperate receiving antennas are used. It keeps locals further away and is a favorite trick of contesters on all bands. With yagis just feed a small portion to a low antenna pointing backwards from the direction being worked.
Ive repeatedly mentioned on here that there are many times where a high angle works best for 160M DX and throwing it away may not be a good idea. It might also be geographically dependent. OTOH modeling has shown that the 1/4 wave Inverted L I had installed for 600M at 160' vertical and 300' sloping to 60' could be improved by 1dB going to a 2 wire tophat. It hasnt been detemined if the missing high angle will be detrimental. Carl KM1H ----- Original Message ----- From: "Jim Brown" <[email protected]> To: <[email protected]> Sent: Tuesday, September 06, 2011 12:47 PM Subject: Re: Topband: Newbie Antenna Question (long) > On 9/5/2011 8:03 PM, Jim Bennett wrote: >> The ARRL Antenna Book, and ON4UN's Low Band DX'ing book, I accept the >> fact that a vertical antenna is the best bet (for transmitting, anyway) >> 160 meters, AND that the Inverted L is basically a vertical antenna. If >> that is the case, does this mean that it radiates just like any other >> vertical, primarily omnidirectional? If it is omnidirectional, does it >> matter in which direction the horizontal portion of an Inverted L is >> aimed? > > The vertical wire is omni and radiates at a low angle, the horizontal > wire serves to resonate it and radiates at a high angle (for local > contacts). A Tee top to the vertical (rather than the L) provides the > same top-loading to resonate the wire, but the radiation from the top > section cancels itself out so that only the bottom section is working. > Thus, a Tee is a better low-angle antenna. > > The K6MM vertical is a compromise for when you can't string something > into a tree. The wire in the tree is likely to work a lot better. With > either, do the best you can with radials and have fun. > > It's worth trying to make that vertical as tall as practical, given your > limitations. Taller means a higher radiation resistance, which means > less loss in your radial system. > > 73, Jim K9YC > > _______________________________________________ > UR RST IS ... ... ..9 QSB QSB - hw? BK > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1392 / Virus Database: 1520/3881 - Release Date: 09/06/11 > _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
