Topband: K9AY end-fire

[Bogdan Chorążyk]

Hi 

Pete N4ZR wrote :

>For this topband season I set up a pair of K9AY loops, each pointed >toward Europe, spaced >130 feet end-fire and phased 180 degrees. I >chose the phasing because of ease of execution >and to avoid >misphasing as a result of impedance mismatches, which I knew I would >have.

  Your fears concerning possible Phase Changes from mutual coupling between two loops are un-justified. The normal diifficulties experienced with Phasing Resonant Elements does not exist in case of non-resonant K9AY loops.
  If you prepare, tune properly and check Phasing Box on your table, assuring you have got demanded Phase Shift and identical currents at respective Output outlets, be sure, that on the field, after coonecting with apropriate non-resonant K9AY loops, the final result will be guaranted.
  According to our experience during that ending Top-Band DX season we have used at our Club Station SP3KEY 4 Square K9AY Array connected to one Receiver and End-Fire K9AY set-ups (located between 21 and 28 meters apart) were connected to another Receiver. The Phasing was 135 degrees Phase Shift.
  We were fully satisfied with operation of these Receiving set-ups.
  The Phase Shift Networks we use offered 135 degrees Phase Shift in case of 160 meter band and - respectively - 50 degrees on 75 / 80 meters band, which has resulted in quite good directivity on 75 / 80 meters band too.



    >The resulting array was quite effective by my lights, certainly >better than a single K9AY >loop, with a considerably narrower >forward lobe and deepish nulls off the sides, at the >cost of a >somewhat reduced F/B ratio.

  >I am considering next year putting up a third support and >arranging switching so that I can >use end-fire pairs of K9AY loops >in 4 directions - 45 degrees, 135 degrees, 225 degrees and >315 >degrees. The models show an RDF roughly like a 1.5 wavelength >beverage, but I think >I\'m skeptical enough to wait and see (and >wonder about my modeling).


  I hope that you will be able to put your plans in practise. 
  After Contest No. 6 on Top-Band during this Winter DX season there is no any doubt about efficiency of our Receive systems. I wish you to achieve the same success.

73, Bogdan SP3RBR

----------------------------------------------------
"3 x Malle" - płyty z filmami Louise Malle'a i konkurs 
z cennymi nagrodami. Z nowym numerem "Kochankowie" na DVD.
http://klik.wp.pl/?adr=http%3A%2F%2Fadv.reklama.wp.pl%2Fas%2Fzwierciadlo2.html&sid=696