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W2IK's "VHF QUICK-STIC"
EMERGENCY FIELD ANTENNA Part II
Design by Bob Hejl - W2IK
all rights reserved
Contents may NOT be copied or used in any form or part thereof without written permission
This is an emergency deployable VHF and UHF antenna that is stored in a pvc sewer tube (which also acts as it's lower base) is under 48 inches yet expands to a whopping 16 feet. It is UPS and USPS shippable. It is so effective that I have 4 stored for emergency deployments or loans. THIS IS PART TWO. Click here to go to the first page: "VHF QUICK-STIC" Masting and Base Construction plans.
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BUILDING THE ANTENNA
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Take the 1/4x20 hex nut and sand all sides (top and bottom and each hex side) so the sheen is taken off just a bit. Now take the 44 inch insulated 14 ga THHN wire and strip away 1/8 inch and solder this carefully to one of the faces (top or bottom) of the nut as shown to the right. Make sure the wire doesn't impede any of the threads or the outer side.
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Snake the 44 inches of wire through a 38 inch length of the 1/2 CPVC tubing. Roughen up the inner portion of the tubing near where the nut will sit. Epoxy the nut so it's pressed into the tubing but flush with the end of the tubing as shown. Do not get any epoxy on the nut threads.
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Let the epoxy set. With the wire dressed out of the other side of the tube, stuff several small pieces of foam rubber into the tubing while holding the wire. Make sure that several pieces, at different depths are inserted. The last piece of foam rubber should be about 8 inches into the tubing. No piece should be shallower than that as you will be trimming from the top during the antenna tuning process. The excess wire should not be trimmed at this time. Put this piece aside.
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Take the 17 inch length of twin lead and at one end strip off 1/8 inch exposing each wire. Bend the wires together and solder. Refer to picture on the right
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Measuring exactly 1 1/2 inches from this connection, remove 1/16 inch of insulation from each wire in the twinlead by melting to expose the wires. At this point, solder one end of the coax with the center conductor going to one wire and the shield going to the other as shown below. Make sure the coax shield doesn't touch the side where the center wire is soldered.
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Mark at the other end (top) of the twinlead which wire from it is soldered to the center of the coax. Dress the coax down the 1 1/2 inches to the shorted end and carefully tape this as shown. DO NOT twist the coax or twinlead. At the other end of the twin lead, cut off one inch of the ONE wire that is connected to the coax braid side leaving the center web insulation and the other wire intact. Expose 1/2 inch of the wire you've marked that is attached to the center of the coax cable by removing the insulation around it. Put this assembly aside.
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NOTE: DUE TO THE FLASH TO TAKE THE PHOTOS, THE CPVC APPEARS WHITE. IT IS NOT. THIS IS CPVC AND IS CREAM COLORED.
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1.Take the 1 1/2 inch brass 1/4x20 screw and slip a 1/4 inch washer over it. Making sure that the screw seats exactly in the center, solder the washer in place as shown.
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2. After the solder has cooled, take the short piece of 22 ga wire, remove 1/4 inch of insulation off one end and solder it to the brass screw head leaving the wire in the screw head slot as shown below
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3. So, now you have a screw with a soldered washer and a wire soldered to the top. Now cut a cardboard circle slightly wider than the inner diameter of the 3/4 inch CPVC tubing and cut a center hole so the cardboard washer fits snugly on the screw as shown.
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Screw this assembly on to the nut/top CPVC section that you've made earlier. Refer to the photo to the right. This will flatten out the cardboard washer.
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Cut off a 2 inch length of the 3/4 CPVC from the length you have yet to use and sand the ends to remove any burrs. Also sand the inner 1/2 inch of one end. Slide the smaller CPVC with the screw assembly into this small piece by inserting the 1/2 inch CPVC length in FIRST starting on the side of the short CPVC you've sanded on the inside until a depth 1/2 inch beyond the screw head is reached. (refer to photo)
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Insert a shim of cardstock around to fill the small gap between the smaller CPVC and the sleeve as shown in BLACK on the photo. This keeps the entire assembly straight after the epoxy has set so you'll be able to easily unscrew the top (thinner section) from the lower section.
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With the assembly held in place as shown, mix and pour epoxy into the sleeve (covering the screw head assembly). Refer to the photo. The cardboard washer keeps the epoxy from oozing to the other side.
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After the epoxy has completely set, remove the shim card and carefully unscrew the assembly. The cardboard washer can remain in the assembly.You are now left with what's pictured to the right.You'll need this assembly later.
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From your unused stock of 3/4 inch CPVC, measure and cut a section exactly 21 inches long. On one end, cement the coupler to the tubing as seen above.
DOUBLE CHECK YOUR WORK AND THEN GO TO PART III
BY CLICKING BELOW:
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