Revised 14 june 2003 1 user manual / assembly instructions cal-av labs, inc. 2d-40a dual-driven element 40 meter antenna description: the 2d-40a is a rotatable horizontal array of two full-size, closely spaced driven elements. Each element is about 70 feet long. The rear element is longer than the f...
Revised 14 june 2003 2 2ea. Coupling sleeves, boom, 3.25” diameter by 17.75” long. 1 kit coupling sleeve hardware. 1 assy. Phasing line, dual rg-213/u, approximately 18.5’ long. 1 lot rivets, closed end, three sizes in individual bags, incl. Extras. 1 kit element hardware 1 kit copper straps and har...
Revised 14 june 2003 3 assembly elements this antenna has been sub-assembled at the factory and then disassembled for shipment. However, it is a good idea to check the measurements on the elements during assembly. The important measurements are those of the exposed lengths, that is, from the outer e...
Revised 14 june 2003 4 note: tape is best removed by unwinding. This will result in a minimum of tape residue on antenna elements. Tape residue on elements can be removed with mineral spirits or wd-40. Joining pieces: except for the feed point, which is joined to the fiberglass, assemble joints as f...
Revised 14 june 2003 5 note: the feed-point and the next 2 joints out are fastened with 1/4"-20 stainless bolts. Be sure that the gray, slotted plastic insulator sleeves that go on the element to either side of the feed point are installed before joining the element halves. Note: rivet holes are sem...
Revised 14 june 2003 6 boom assembly identify the 5-foot boom center piece, and place it on a table or bench for convenience. The center piece is the only 3” diameter tubing that is swaged at both ends. Place the boom center piece on the table with the handwritten instructions and legends facing up....
Revised 14 june 2003 7 attaching the boom to element mounting plates it is now necessary to provide adequate support of nearly the entire length of the boom, because you will be adding significant and uneven weight to the boom in the next steps. This can be accomplished with a long table or 3 sawhor...
Revised 14 june 2003 8 6. With one element mounting plate held level, using a small bullet level, check level on the other plate. 7. Twist one plate with respect to the other by grasping them and turning in opposite directions about the long axis of the boom. Now trial-tighten the twelve quarter-inc...
Revised 14 june 2003 9 note: if the antenna is to be painted, now is the time to paint the boom. However, if you do paint the boom at this time be sure to take steps to mask the hairpin assemblies and connecting straps so that they do not get painted. See appendix f, “painting instructions”..
Revised 14 june 2003 10 final assembly attaching and connecting the elements this procedure takes a space of 25 by 75 feet. This can be a driveway, rooftop, etc. Placing the boom on a couple of sturdy tables or sawhorses will make this assembly much easier. If absolutely necessary, it can also be do...
Revised 14 june 2003 11 note: the phasing line must be installed so that there is a 180 degree phase reversal in the connections to the elements. The ends of the phasing line have been color coded to facilitate making this connection correctly. 3. Identify the terminated twisted pair of the phasing ...
Revised 14 june 2003 12 note: use an adequate number of people, patience, common sense, and great care. These will get your new antenna into the sky without damage to it or to you! If you are not experienced with installation of larger antennas, we strongly recommend that you get some very experienc...
Revised 14 june 2003 a-1 appendix a specifications for 2d-40a description: the 2d-40a is a 2-driven-element array for the 40-meter amateur band. It features full size elements, an internal phasing line, and an innovative integral balun feed system. This beam has gain comparable to a 2-element yagi, ...
Revised 14 june 2003 b-1 appendix b patterns and graphs the following patterns are based on nec-2 modeling. They do not represent measured patterns. However, both forward gain and relative response front to rear (f/r ratio) have been verified (for relatively clean sites) by antenna range field stren...
Revised 14 june 2003 b-2 figure 2-b 2d-40a elevation plot (antenna mounted 70 feet above earth) figure 3-b 2d-40a azimuth plot (antenna mounted 70 feet above earth).
Revised 14 june 2003 b-3 the following vswr vs frequency plot was generated by the nec-2 model. Actual measurements of real antennas in the field have typically reproduced the general shape of this curve. But the measured curves have shown a somewhat wider bandwidth between the 2:1 vswr points. This...
Revised 14 june 2003 c-1 appendix c mechanical drawings 42 59 15 15 18 19 27 50.5 66 in 52 in 44.5 in 409 in (changes with tuning) (maximum boom center to element tip) (changes with tuning) individual tubing dimensions are "exposed" lengths not including portion telescoped into next larger sized tub...
Revised 14 june 2003 d-1 appendix d parts list 1 assy. Boom, consisting of: 1 assy. Mounting plate, boom-to-mast, consisting of: 1 ea. Mounting plate, mast, dwg. No. 020218-001-0001 4 assy. Clamp, 2", stainless, assy/n mc9200ssa 1 ea. Mounting plate, boom, dwg. No. 020215-001-0001 4 assy. Clamp, 3",...
Revised 14 june 2003 d-2 1 ea. Upper bushing piece, acrylic, dwg. No. 020221-001-0001 4 ea. Screw, 10-24 x 1", phillips pan head 8 ea. Washer, flat, stainless, an-960c10 4 ea. Nut, elastic stop, 10-24, stainless 1 ea. Block, insulating, acrylic, dwg. No. 020221-003-0001 2 ea. Screw, 10-24 x 1" stain...
Revised 14 june 2003 d-3 1 ea. Washer, flat, an-960c416 1 ea. Nut, elastic stop, 1/4"-20, stainless 2 ea. Clamp, hose, all stainless, 71/95 mm, upg p/n 4150 2 kit, strap, connecting, hairpin to element, consisting of: 2 ea. Strap, connecting, 0.625" wide, 8.5" long, dwg. No. 020219-003-0001 8 ea. Wa...
Revised 14 june 2003 d-4 6 ea. Washer, flat, an-960c-416, stainless 2 ea. Washer, lock, split-ring, 1/4", stainless 2 ea. Nut, 1/4-20, stainless 2 ea. Tube assy., 2.50" dia. 71.875" overall, all exposed, with 41" internal doubler, dwg. No. 020506-002-0001 2 ea. Tube, 2.25" dia., 0.125 wall, 58.75" o...
Revised 14 june 2003 e-1 appendix e operational notes feed system description for the n7cl array the n7cl version of the two element driven array has been described incorrectly as being essentially an hb9cv antenna. While the n7cl driven array antenna is definitely in the same class of antenna as th...
Revised 14 june 2003 e-2 6. The design of the feed system rigidly enforces precise electrostatic balance for the array. Balance is maintained with regard both to the feedline connection and to the connection to the tower. This makes the antenna much quieter on receive and eliminates the need for a s...
Revised 14 june 2003 e-3 tune-up instructions for the cal-av labs, inc. Model 2d-40a antenna this manual contains tabular data on the tuning and matching stub shorting strap positions and element lengths for an antenna mounted at the minimum recommended height of 1/2 wavelength above local earth and...
Revised 14 june 2003 e-4 antenna settings for 2d-40a mounted at 70 feet (one half wavelength) frequency (mhz) delta (inches) tip length (inches) 6.962 0 50.5 7.030 -5 45.5 7.099 -10 40.5 7.170 -15 35.5 7.241 -20 30.5 7.313 -25 25.5 figure 2-e tip lengths vs frequency (70 feet) if the antenna is to b...
Revised 14 june 2003 e-5 however, if you wish to achieve perfection at some particular frequency, here is the procedure to completely optimize the antenna for operation on a particular frequency: 1. If the minimum swr is low enough to make you happy, proceed to step 6 below. If not, then adjust the ...
Revised 14 june 2003 e-6 antenna settings for 2d-40a mounted at 140 feet (one full wavelength) frequency (mhz) delta (inches) tip length (inches) 6.948 0 50.5 7.015 -5 45.5 7.084 -10 40.5 7.154 -15 35.5 7.224 -20 30.5 7.296 -25 25.5 fig 3-e tip lengths vs frequency (140 feet) if the antenna is to be...
Revised 14 june 2003 f-1 appendix f painting instructions general: should you paint your antenna? We think so, but it's your decision. Here are the facts: operational effects: nil; a thin dielectric coating (paint) between the metal and the air does cause changes, but they would be very difficult to...
Revised 14 june 2003 f-2 has some very nice attributes. Among them are that it can easily be removed with acetone, even after it is dry, and that it is very easy to touch up, while wet, after it's dry, or days later. It will oxidize a bit after years in the sun; even then, it can be cleaned with an ...
