[TowerTalk] 80m 4 square - revisted

Thomas Collins fantasz at outlook.com
Mon Jan 20 17:38:10 EST 2020


Gentlemen,

My plan still is to to install a 80m wire 4 square with 4 FCP's per K2AV's article:   https://k2av.com/Olinger_NCJ_article_on_FCP.pdf    On the the bottom of page 5, Guy mentions using an FCP on 80m.

In the article, Guy uses an isolation transformer, and also mentions using one on 80 with 5 less turns (15T for 80, 20T for 160).

I have modeled the array, and it does show decent gain and F/B.   I'll be using a Comtek box for switching, and purchased phasing cables from DXE, which are the ones with the ferrite beads on the end.

With a Zoom 230 and a OSL calibration kit, my plan is to install one element with the FCP, measure the impedance at the feedpoint, and if necessary, build a matching network to get from the measured impedance to 35 ohms +j0.  Then repeat for the other three elements.

Question:   Is the choking impedance of the phasing cables with the beads sufficient for an FCP elevated radial system, or do I need the total elimination provided by the isolation transformer (as noted in Guy's article)?

Thanks!

Tom, N2SR



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