[TowerTalk] 160m L impedance???

John fraz1 at bellsouth.net
Mon Dec 8 15:26:51 EST 2008


OK gurus......

A 1/4 wave inv L.  Vertical to 66 feet, the balance horizontal.  32 radials on top of the ground.  Range in length from 35 to 68 feet; a good mix of those lengths and using 14 solid copper insulated wire.  At the feed point, the lowest SWR measures 3.2 at 1.820 MHz. But, the impedance is measuring 80 ohms +/- !  I show 7 mh and 1050 pf.  At the shack (fed by 75 feet of BuryFlex, I see the lowest SWR of 1.2 at the same freq, 1.820.  The impedance is 60 ohms.

I used both my Autek RF-1 and the MFJ-259.  They agree; probably wrongly.  I have NO BC stations within 10 miles, especially strong ones.  My soil is a sand, top soil mix; probably more sand.

Why am I seeing such a high impedance at the feed point.  The "bad" news is that the antenna works ;-).  128 in two seasons.

73 John K4NP   (this should bring on some beauts)


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