Hello,
I was helping a friend put his ?postage stamp lot --low to the ground? 80
meter loop on 160. So, we opened the loop to cause a ½ wl 160 antenna
folded into a polygon.
Placing the MFJ-269 analyzer at the loop (open or closed) feed point shows
fairly appropriate readings at 3.600 (R 98 +J25) , but anything outside this
range down thru 1.8Megs and below, or up toward 7Megs shows continuous R
values of ZERO with a varying j value. Measurements were taken right at the
feedpoint, which is 45 degrees off center (approx).
My concern is the ZERO R value -- for even occurring, but also that it
occurs over such a very wide range of frequencies
The 269 is working appropriately with 25, 50 ohm and 100 ohm calibration
loads and was used to cut feedlines for 160 and other bands and indicated
properly during that exercise.
Possibly with the antenna being sooo close to the ground, Z?s way get out of
hand. EZNEC modeling shows low ?teens? feed R?s , but the model does not
include houses, power lines, neighbors cars, etc.
Any comments or constructive criticism from any one on this Analyzer dilemma
?
Oh, QTH is within the city of Houston, and unfortunately, we do not have a
spectrum analyzer to look at band of interest noise levels or interfering
sigs.
Thanks and regards....Rick ? W5RH
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|