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K2US |
Bob Ehramjian Phone: 843 833 1940 E-mail: k2us@hotmail.com |
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512 Springfield Road, Pawleys Island, Georgetown County, SC 29585 |
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US Tower HDX-589-MDPL |
The rotator is a prop-pitch from a WWII B24 Bomber. |
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ANTENNA DESIGNED BY |
W6ZA Wayne Lowrance and K2US Bob Ehramjian using Nec-Wires 2. Constructed by: K2US Bob during August 1996 at his QTH inPawleys Island, SC. This is a DUAL BAND 20/15 Meter QUAD. |
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This BIG QUAD probably is the OLDEST 20 Meter BIG QUAD in the WORLD. It has been up continuously since September 1996. If you have a long boom 20 Meter QUAD of more than 4 elements and it is has been in longer continuous use than my QUAD please e-mail me. I have stated this during my contacts for the last five years and haven't heard otherwise. |
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ANTENNA |
6 Element Quad on 20 Meter Element spacing 12-12-12-12-12 BOOM Length 60 feet. |
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ANTENNA PERFORMANCE QUANTITIES using EZNEC +5.0 at a height of 100 feet above average ground. |
6 Element Quad on 15 Meter Element spacing 10-12-12-12-10 BOOM Length 56 feet. |
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FREQUENCY |
20 Meters 14207 kHz |
15 Meters 21300 kHz |
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FORWARD GAIN (dBd) |
16.78 * |
17.81 * |
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* At the elevation angle |
9 degrees |
6 degrees |
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POWER GAIN over DIPOLE |
40 |
60 |
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FRONT to BACK |
62.74 (71 MAX) |
36.97 (50 MAX) |
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FEED POINT IMPEDANCE (ohms) |
49.9 + J 0 |
50.1 - J 0.9 |
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COPPER WIRE SIZE (solid copper) |
AWG #12 |
AWG #12 |
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ANTENNA WIRE LOSSES (dB) |
0.38 |
0.37 |
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ANTENNA EFFICIENCY (percent) |
91.6 |
91.8 |
ADDITIONAL INFORMATION
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This antenna is installed at a location beside a very large pond and within one mile of the Atlantic Ocean. The actual antenna FORWARD GAINS of both ANTENNAS would be HIGHER than the listed values because the ACTUAL GROUND has a much higher conductivity than AVERAGE GROUND.
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Both driven elements are fed separately using 50 ohm coax with 9 FERRITE beads around the coax at the feed point as a choke balun.
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All QUAD loops are complete there are NO TUNING STUBS.
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The ALUMINUM BOOM is 3 inches in diameter and is GUYED with 3 sets of phillystrand GUYS, over the top and at 120 degrees and
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at 240 degrees.
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The fiberglass spreaders are extremely strong with a wall thickness of one-tenth inch. The spreader OD is at max 1 inch and therefore the antenna array has low wind loading for its size.
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Wire attached to the spreaders using NYLON WEBBING and stainless hose clamps. Method developed by Bob Ehramjian K2US
Bob Ehramjian and two of his four grandchildren, his grandsons, Jack and Sam. Both GRANDSON's
live in GEORGIA.
Aerial photo of the K2US antenna on the 8th green of the Founders Club Colf Course in Pawleys Island South Carolina.
Picture taken from K1DD Dan DROST'S (K1DD) CHIPMUNK RAF TRAINER in 2012 by K2US.
I would like to acknowledge my friend of 50 years Woody K2UU who is known as the LI/NY Tower Guru. He has literally helped hundreds of Hams with their installations including many of the big contest stations including: N2AA/ K2GL, W2A KN3O, W2AX, K2LE, W2HCW, W2VP, K2ON N2NB/NJ7N K2BQ etc. K2UU Woody is shown in a March 2012 photo here with me. He repaired my tower, a US TOWER HDX-589-MDPL, over the years and did a tremendous job for me for which I am very thankful.
The BOOM is GUYED over the TOP and at 120 degrees and 240 degrees with PHILLISTRAND GUYS
PICTURE TAKEN AT PAWLEYS ISLAND, SC FROM DAN DROST'S (K1DD) RAF CHIPMUNK TRAINER BY BOB K2US IN 2012.The tip of the left wing of his plane can be seen with the left trailing edge pointing at Bob's QUAD in the distance. In the foreground is OCEAN HIGHWAY (Route 17) less than 1 mile from the ATLANTIC OCEAN toward the bottom of the picture. The EIGTH FAIRWAY runs at right angles with OCEAN HIGHWAY with the QUAD of K2US near the green of that hole. The small house just to the right of the QUAD is his wife's SOLAR HEATED GREENHOUSE. At the very top of the picture the beautiful WACCAMAW RIVER can be seen. The river is running from the left top edge of the picture to the right top edge.
January 2013, Bruce BRAINARD (N4JHY) helped Bob repair his quad. New relay box, new driven element feeders, and a new set of wires,15 and 20 meters for the reflector element damaged by a riding lawnmower when the antenna was tilted down on the ground. Seven of the 9 ferrite cores at the feedpoint of the15 METER QUAD can be seen in this picture.
