Hi Pete, well we operated on the West side of the IH 35 corridor, which
means we were on the Balcones escarpment ( a north -south fault line
uplift), in an old rock quarry. Solid rock under our 20m loop, but the
quarry was open to the North, South and East. (clear look to New England,
and East Coast and SE.) Some trees to North. Shallow wall to West with loop
higher than that.
We were about 10 fee below the crest of a hill that then fell away to West
for more than Fresnel Zone until next hill (at 20m and 40m).
Our ground might have been good for shallow depth of football field,but in
our reflection zones it was terrible conductivity due to rocks.
The loops outperformed our 3 vee beams of prior years. The vee beams are
great in favored directions, but we needed to keep them low like first
year's 10 feet. Going over 15 feet high, they became DX antennas! Worked
West coast at start of Field Day and nothing in between. Our loops on 20m
were equal performers in any direction both near and far skip, but it was
approx 160 m loop used on 20m the first year, and bigger next years.
We plot the sections worked year to year and of course look at dupe sheet
totals for call areas. During day, a loop on 40m works mostly 5's but
really shines after dark. That loop was 330 feet around, 20 feet high, and
worked HI as well as most of FD sections last year. I think we were 5
sections short of full run. Never seem to find Alaska. Yukon Terr. is
pretty hard too. It was over a concrete basketball court on crest of the
hill. All loops used on SSB with battery QRP class, (5 watts).
We have 9 years at same location so have gathered a lot of knowledge on the
propagation off that hill with various antennas. Ran verticals and G5RVs
for comparisons some years.
-Stuart Rohre
K5KVH
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