thank you, Tom - great info!
> From: [email protected] > To: [email protected]; [email protected]; [email protected] > Date: Mon, 5 Nov 2012 12:37:34 -0500 > Subject: Re: Topband: Further discussions on EWEs > > > Tom, et al: is there data that nail down the horizontal wire to vertical > > wire ratio? I see in that write up by wa1on mention of 2.25:1 h to v > > but...is that some rule that can't be violated or.../ > > > > For instance, assuming a vertical section height of 10' I could run a > > longer horizontal section but don't know if that gains me anything. > > I can't imagine why there would be some set rule or guideline, except with > many qualifications. I'm sure there is some general range of lengths vs. > height for various configurations. The ideal shape would be rectangular with > source and load centered in the shorter vertical wires, which is the > equivalent of a base-fed EWE over perfect ground. > > The horizontal part or component of the antenna works best when it behaves > most like a transmission line with a velocity factor of unity (ideally > faster than light). The longer it is and the wider it is spaced, and the > poorer the earth below the antenna, the more the system responds to unwanted > signals in the horizontal mode. > > The vertical component of the antenna wires acts like two verticals, and is > the desired signal response. > > You can see the obvious conflicts. If the vertical section is taller, > horizontal spacing is wider and that response increases. If the length along > earth is longer, the verticals are separated more and this increases > sensitivity of the verticals (until they are 1/4 wave apart) but it also > makes undesired horizontal sensitivity increase. > > There are a half dozen things that can make one thing better while making > other things worse. Everything, including characteristics of the earth and > things around the antenna, would interact. > > If you really wanted to optimize an antenna like this, you would have to > make it two short verticals that are phased. After all, that is all the > antenna actually is. > > 73 Tom > > _______________________________________________ > Topband reflector - [email protected] _______________________________________________ Topband reflector - [email protected]
