Topband: Vertical array

[Lee K7TJR]

w5uc>  Looking at the effect of varying the 
phase by a small amount my simple mind said: I don't know the angle 
at which local interference arrives. The only thing I can guestimate 
is the arrival angle of stateside & DX signals, therefore I can 
possibly reduce the overall amount of signal in the receiver front 
end  by increasing the high angle F/B.<

   I think we all would like to know the arrival angles of signals however it will likely be a long time before we do. Enter the often heard comment that one can never have enough antennas. What I see here on Beverages and vertical arrays is that signals within about 500 miles show 'Generally' no directivity on any of my arrays and a slight bit further out on the Beverages. My vertical arrays do not show limited directivity in their plots until about 80 degrees elevation if we can believe the computers. Beverages slightly lower with many lobes. I also do see the early morning high angle signals from JA/UA0 at this Qth. I am working on a high angle array to the West. If it is local man made noise you are talking about you might benefit from a noise canceller.
    Personal observation is that if we could educate the lids to stop transmitting right on top of the DX a lot of these interfering signals would go away. Also using the maximum attenuation you can get away with in your radio may increase its signal handling ability. Roofing filters rule! they really help on handling loud signals amongst small ones. I have added an animated graphic to my web page that shows what happens with varying the phase in steps on a 2 element array.  "http://www.k7tjr.com/rx1comparison.htm" . As per my previous comment some of the parameters are rather insensitive to a few degrees of shift. 
    Tod  K0TO recently mentioned using the DXE variable phase unit with active two verticals. I hope he continues to post his results here so we can all see. 
    Three active or passive  antennas in a triangular array make a really nice array as W4TV mentions. I have the data but it will be a bit before I can put it on the comparison page. Good RDF, F/B,  and 6 directions.
     I have steered away from loop type antennas as in my models I see wildly varying front to back with elevation angle. In my models at very low elevation angle the pattern always widens out and the RDF suffers. I have programmed loops as high as 80 feet elevation and see no improvement. If you optimize the front to back by setting the phase delay for a low angle, there is very little front to back at a high angle. This makes a variable phase network or cable length switching necessary with loops for all different conditions. This is much less prevalent in vertical arrays. Verticals show a much cleaner low angle response in my models than any others I have modeled. 
    For general DXing I suppose having a variable phase is OK but in contesting is seems to me out of the question. 

  Lee K7TJR Oregon