Topband: HIZ 8 Circel Diameter.....

[Lee STRAHAN]

  Hello Frank and All,
      First you must tell us what you are expecting to make better with a Hi-Z array. Do you want Better front to back? Do you want Front to side? Do you want better signal to noise ratio? You want narrower beam width?  Not ALL things get better at once with size.
    To my knowledge, with this phasing scheme  Just changing the spacing on your current 8A array will do more harm than good to the overall performance. The front to back will remain about the same. The front to side lobe will get severely worse to where the side lobes are only down about 8 dB. The RDF or signal to noise improvement of the 8A is the highest commercially available anywhere. It only changes 0.2 dB better theoretically going to 300 feet diameter. There is NO conventional wisdom that I am aware of that tells us the array should be better with a larger footprint. This array has ALL elements active all the time. Raising the foot print to 300 feet and going to 4 elements active per direction will only improve the front to side rejection but suffer from a 0.5 dB or so less signal to noise improvement. I could change the phasing on the 200 foot diameter array and lower the side lobes easily. I choose to stay with the higher RDF. 
   Theoretically it is possible to model 8 elements like this and get over 16 dB of RDF ( I have the Eznec model) or signal to noise improvement. Unfortunately theoretics and reality  don't match. The current array from Hi-Z (8A) requires all of the transformers and components plus the cable lengths and element placement to be quite accurate (around 1% for each sub part) to even do the 13.5 dB of RDF. It is at this time likely NOT within a Ham budget to actually build an array accurate enough to even attempt getting more RDF or signal improvement out of 8 Elements with 8 directions. I even tried 12 elements in 12 directions all active.
     There are installations using two arrays phased together to get approximately 3 dB  higher RDF. Even this is tricky but it is being done. At this time phasing two or more arrays has the best chance. First we know the smaller arrays work but can be affected by other antennas and power lines etc. A higher RDF array gets affected by the same things only worse. So phasing two arrays that are not affected as bad have a better chance of working in the environment than a single SUPER RDF array.
          Now,  If it seems your 8A only array just simply does not have enough gain or the noise level from it remains extremely low because of your low noise area contact me directly as we have a pilot program going on right now that reduces the Noise figure of this array by nearly 9 dB. Its not really simple but it works. This does NOT change the lobes or front to back or anything about the patterns only  the VERY  VERY weak signal performance.
  I get questions all the time about; can I make it better if I make it bigger. NO: if changing size would have been better I would have provided  it a long time ago. I have 100's of acres here to try things like that. I even looked at a 4-square of 8 element arrays. The beam gets so narrow you have deep gaps between the main lobe. 
   Ahhh so many antennas so little time.  Thanks for the question Frank, I hope this has been helpful.

73,   Lee K7TJR  Hi-Z Antennas.

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of dl8yhrfrank--- via Topband
Sent: Saturday, March 03, 2018 11:30 AM
To: topband at contesting.com
Subject: Topband: HIZ 8 Circel Diameter.....

Hi everyone...
Did annyone has experience in using more wide spacing the 8 circel rx arrya?
Im running the hiz 8a lv2 160-2 arrya in a 200 foot spacing in the fields on a litel hilltop away from man made noise and have lots off space their so i think about to get it up to 300 foot spacing to optimize it for 160 Annyone tryed it ore can model it maybe if that will give more performace on 160?
Anny comments vy welcome
Best wishes
Frank
DL8YHR

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