Carl
I'd be happy to have your help with this. I will be brief to avoid bandwidth:
The K1ZM 4 Sq Array (NY) - A classic 4 square array with EXTENSIVE Ground
System
1) (4) 138 foot vertical radiators - insulated bases
2) 1/4 wave (free space) spacing down the SIDES of the square - DIAGONALS are
about 192 feet
3) (4) RG 11 (Foam) 1/4 wave (electrical) phasing lines connect each radiator
to a hybrid coupler which sits in the center of the square
4) Hybrid Couper produces 0,90, & 180 degree phase angle outputs
5) Directivity is achieved by feeding LEAD radiator at -180 degree phase, the
(2) SIDE radiators are LAGGED at -90 degrees and the REAR radiator is fed at 0
phase. Phase angles and current distribution are achieved by precision
toroids and capacitance values within the hybrid coupler.
6) Array directional switching is instantaneous by electrically switching the
hybrid to MOVE the (4) phase angle outputs - in harmony - around the
radiators.
7) Radials - on ground, probably 2,500 in all directly under these radiators
AND in (8 other CLUSTERS) in the near field.
These clusters are under an 80M 4 square and other 160M antennas which are on
the same hill removed slightly to the North and South of the 160M (4) square.
Ground area covered by radials is about 1.6 acres.
8) Extensive use of Agway "hardware cloth" complements the radials. About
(15) fifty foot runs of hardware cloth 48" wide sit in the CENTER of the array
starting at the hybrid coupler and run out like the spokes of a bicycle to all
headings. The hardware cloth is connected to the hybrid coupler ground and to
all radiator ground systems and to all the other clusters.
8) Typical front/back (as measured in daylight locally 7 miles away at N2TK -
8AM with 100 watts - NORTHEAST vs SOUTHWEST shows signal reports as follows:
NE (away from N2TK S6)
SW (toward N2TK S9 +10DB = approx 28DB)
9)A 1KW dummy load safely dissipates any power "kicked" out of the hybrid due
to dissimilar/mismatched radiators
10) System is fed with Rg213 50 ohm coax - 12V switching line is #14 Romex to
remote switch in the shack
If there is any more I can provide, pse let me know. I am very pleased you
have offered to take a look at this - especially this notion of "off the back
high angle radiation." If I understand this possible scenario, it is saying
the following:
1)Propagation, at the time, was favoring high angle lobes off the BACK of my 4
square (when I beamed South)
2) Propagation, at the time, off the FRONT of the 4 square array was not
favoring the more normally useful (for this path) LOW ANGLE lobes.
I think that is what NM7M has suggested, if I understand it correctly. And
Bob may be right on - dunno at this point. It is certainly possible I
suppose.
The BASIC issue here is why did NL7Z PEAK from the South?
It was RECIPROCAL as he says I also came up 3 S units when I aimed my antenna
SOUTH.
Others around the country with directional beverages have also confirmed that
signals were arriving from the SOUTH.
The multipath ECHO I heard would seem to indicate a delay caused by TWO PATHS
though. The AMOUNT of delay noted would seem to indicate one signal travelled
FURTHER than the other I was hearing.
I will re-read Cary Oler's response again to see if it addresses this issue.
Perhaps it does.
It probably isn't worth investing TOO much more bandwidth on this one.
At the end of the day we may wind up with this simple, two word explanation:
..IT HAPPENS!
Thanks again for your help.
73 Jeff
K1ZM@aol.com
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