James, Thank you for your observations and recommendations. I respect and appreciate the wisdom. However, I think I will get up close and personal with the modeling software and see what I can learn. Maybe it is possible to substantially kill more of the high angle response, as the verticals do 'for free.'. 73, Bruce W8RA
________________________________ From: James Wolf <[email protected]> To: 'Topband Reflector' <[email protected]> Sent: Monday, February 10, 2014 5:29 PM Subject: Re: Topband: Shared Apex Loop Array The antenna geometry indicates that it should perform similar to a Waller Flag *under the same conditions*. The Waller flag though, (as Tom has alluded to) has more spacing between the loops and is usually mounted higher in the air. Height above ground is important. Raise your model up to 100 ft. Also, since the currents in the center vertical wires are out of phase, you should be able to eliminate three of those wires. Tie all the wires together at the top and at the bottom, and use just one wire from top to bottom. Jim - KR9U -----Original Message----- From: Topband [mailto:[email protected]] On Behalf Of Andy Ikin Sent: Monday, February 10, 2014 4:12 PM To: bruce whitney; Topband Reflector Subject: Re: Topband: Shared Apex Loop Array Bruce, I have considerable experience with loop arrays; whilst they are good performers in an electrically noisy environment, they suffer from poor directivity at higher angles. This can also be seen with EZNEC models by looking at the AZ Plot with an Elevation angle of say 40 degrees. The directivity and RDF is much better with a pair Phased Flags for example. Other issues, Tom has mentioned a too close element spacing which will lower the array gain. Also there is the issue of array stability i.e. a minor phase or amplitude error will completely screw up the pattern. 73 Andrew G8LUG _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband
