Make-it-yourself devices archive page 8
weather radio antenna:

My home is about 25 miles away from the nearest National Oceanic and Atmospheric Administration Weather Radio All Hazards program transmitter. The station broadcasts weather reports and forecasts and emergency messages about any hazardous situations. My weather radio receives their broadcasts loud and clear most of the time. But when it's raining sometimes the signal fades away because the rain absorbs some of the signal. I had been using the radio's built in telescoping rod antenna. It seemed to me, it would be prudent to have more reliable reception of those signals. So to get a stronger signal and better reception, I made a high gain antenna and put it in my attic.

I got online, found a design for an antenna, looked around the premises for the materials, thought of how to implement fabrication, built the design diagramed below, installed the antenna in my attic, and now have more reliable reception. I don't use the radio much. I usually get weather forecasts online were they are accessable quicker than listening to a repeating loop of messages on the radio until the forecast is given. But the radio is there if needed in an emergency. It has battery backup if the power grid goes down.

To make the antenna I drilled 1/8 inch diameter holes in a 1 1/2 inch by 1 1/2 inch by 5 foot piece of wood. A single straight piece of wire goes through each of those holes. See the diagrams below. I used wire from clotheshangers. One hole is drilled for each of four of the five wire elements. The fifth element (shown in red) actually is made of two pieces of wire. That two-piece element is called the driven element and is where the antenna signal is developed. It's probably easiest to drill two holes for that fifth element (more about that later). I made my antenna with just one hole, drove a 3/8 inch long piece of cylindrical plastic into the hole, inserted one wire into either end of the hole, pushed in 3/8 inch long pieces of wire as shims to wedge the long wires securely in place. The plastic spacer keeps the two long wires separated. The second diagram below shows the connection of the RG59 coax that carries the signal to the weather radio. I sand papered a 1/4 inch or so wide area of wire next to the wooden boom, then soldered the braided copper coax shield to one driven element and soldered the coax center conductor to the other driven element piece.

I hung the antenna using string tied to nails driven into roof rafters in my attic. The antenna is almost directly above the wall on which the radio is mounted. About 5 feet of coax carries the signal from the antenna to the radio.

If I make another such antenna, I would use two holes for the driven element. The two holes could be, say 1/4 inch on either side of the design position of the driven element. I suppose being off by 1/4 inch would have no significant effect on the antenna's performance. Using a single hole allows each wire to be inserted for something under half as far into the wood boom. So the shim method probably isn't as secure as how I secured the other elements. To secure them I ran a doubled length of rubber band through the hole, stretch the rubber band tight to reduce its thickness, inserted the wire and released the tension on the rubberband. To get the rubber band through the hole, a loop of thin, stiff plastic cord can be pushed through the hole, the rubber band inserted in the loop, and the loop pulled back out of the hole, pulling the rubber band with it.

I used a five element antenna (this design is called a Yagi antenna). A yagi can be made with two or more elements. The more elements, the stronger the signal and the greater the antenna's ability to pick up the signal toward which it is aimed and reject interferring signals from other directions. It seems that a 3 element yagi is perhaps a good compromise between performance and ease of construction. You can go online and get specifications for the length of the elements and their spacing. The Weather Radio All Hazards broadcast are all very close to 162MHz in frequency. Here are some web sites you can use to get the specs. (7 element yagi) (3 element yagi) (1/4 wave vertical with 4 horizontal ground plane elements) (3 element yagi)

If you live closer than 20 miles of a transmitter, you won't need such an antenna (unless you also want to pick up a more distant station). I'm guessing that if you live farther than about 40 miles you probably won't get acceptable reception even with the antenna. The distances are somewhat affected by whether you are at a high elevation up above any obstructions to the signal or down in a valley shadowed by hills and such. If you want to try this, try to get a radio with a jack for an external antenna. I have a radio with a built in jack in my car. It might also be possible to modify a radio that has no built in jack but does have a telescoping rod antenna. That's what I did for the weather radio I use in my home. I mounted a jack for the RG59 cable on an angle bracket that I bolted to the outside of the radio. I opened the radio case, unsoldered the lead going to the rod antenna, and soldered the lead to the center connector of the RG59 connector. There's a picture somewhere here of that radio.

One note about weather radios. The two radios I have are older radios without a feature called SAME. The SAME technology allows you to program the radio so that the radio will turn itself on if a warning or emergency message is being broadcast for the area in which you live. My older radios switch on if a message is being broadcast for any area within the transmitter's range. If I leave my radios on during thunderstorm season, they switch on so often that it becomes a nuisance. So I usually leave the radios turned off. I suppose with SAME technology there would not be such a problem.

The narrow lines are wire, the wide section is the wooden boom that holds the wire. The red line is the wire from which the signal is taken by a cable that runs to the radio. The connection of that cable is shown in the second diagram. The distances in inches from left to to right, measured from the first element, are 0, 12 1/4, 17 5/8, 27 1/2, and 41 9/16. The lengths of the elements are 1) 40 7/8, 2) 37 5/8, 3) 37 5/8, 4) 36 11/16, and 5) 36.
The RG59 cable's braided copper jacket is bundled, wrapped around one clotheshanger wire, and soldered. The cable's center conductor is soldered to the other driven element wire.

Pants waist tightener:

Most of the time when I buy a pants, they do not fit quite right. Either the inseam is too long or the waist too big. If the inseam is too long I most always just fold up the cuff. If the waist is too big, I have used several methods to take up the extra material.

The easiest is to fold the materail at the waist band, lay the folded area on a block of wood, then use a nail and hammer to punch two holes, one above the other by about 1/2 inch or so. The distant from the fold to the holes should be however much needs removed to make the fit right. I make the fold in the waist band above the pocket. That is where the waist band does not press against the body and so will cause the least irritation. If a lot of slack has to be taken up, do a fold above both pockets.

Then run a piece of shoestring or heavy chord through the holes, pull it tight, and make a square knot.

Here's a picture of the fold I made in one pair of pants and the piece of shoestring. I wrapped the cut end of the shoe string with thread to keep it from fraying and dabbed on a drop or so of waterproof glue to keep it from coming apart. A dab of glue on the shoestring knot will help make sure that knot never works itself loose.

Another design is shown below. Make clips out of clotheshanger wire by bending with pliers. The clips can be about an inch across. First make a U-shaped clip. Punch the holes in the waist band. Insert the clip through the holes. Finish bending the clip. Cut a piece of bicycle inner tube to slip onto the clips to pull them together tightening the waist band. Or you can use a thick rubber band that is sometimes used to hold broccoli stems together. My guess is the inner tube band will last longer.

This design takes longer to make but if you are careful to get the tension on the band just right, it makes for a comfortable fit that has a little give especially for when you bend or sit.

This is what the clips look like when finished.

This is a diagram of the finished tightener.

Electrified garden fence: Keeps out vegetable eating varmints:

Groundhogs, rabbits, and deer were eating the vegetable plants in my garden. I tried shooting the groundhogs and rabbits. That takes too much watching and waiting and it is not safe for neighbors whose property and houses are well within range of stay bullets. I tried filling in the holes of groundhog but instead of moving elsewhere they just kept on digging new holes.

Finally I got out an electric fence power unit that years ago was used to electrify a fence around a cattle pasture, plugged it in and tested it by shorting the hot output to the ground terminal post with the metal shank of shrew driver, being careful to hold on to the screwdrive by its plastic handle. As the screwdriver shank was pulled away, I could hear and see an electrical arc, over a sixteenth of an inch long stretching between the hot terminal and the srewdriver. After sitting for almost 30 years it still worked.

FI strung copper covered single strand telephone wire around the garden, twice. A wooden post was set at each corner of the garden. One run of wire was held about 2 feet off the ground, the other run was 5 or so inches off the ground. The upper strand was about at he height of a deer's nose. The lower strand about nose high for groundhogs and rabbits. The power unit was mounted on a pantry wall in the house. A plastic tube from a ball point pen body insulated the telephone wire where it run through a hole drilled through an exterior wall. Some used electric fence insulated, held the wire in place on a pole about twelve feet from the house. The rest of the fence insulators were put on the nearest corner post to secure the wire there. At the other 3 corner post, I improvised insulation by slitting black plastic 1/2 inch diameter polyethylene water pipe lenghthwise and forcing the slit tube onto the wire where it was otherwise contact each of the three corner posts. The lower wire sagged way too much to just leave it hang without touching the ground and shorting out. So used empty plastic detergent and bleach bottles to hold the lower strand off the ground. I tried a half-dozen or so ways to attach that lower wire to the plastic jugs. The easiest way was to cut through the upper end of the loop the formed the contrainer handle. The wire could then be push inside the handle loop.

I've used the fence for about 5 years now and it has done a very good job of protecting the garden. A couple of times a rabbit has gotten in, probably by just jumping over the lower wire. Once a groundhog got it but could not get back out. I found him in the garden hiding under squash leafs, apparently dazed by having being shocked by the fence. Without the fence, I likely would have either given up having a garden or tried to keep a dog to keep animals away. But that would mean the dog would have to be free roaming and that would inevitably cause problems with neighbors.

The fence power unit was made for large animals, cattle and horses. It is powerful enough to not short out easily when a few blades of grass grow up to touch it, usually the grass will be burned off by the high voltage current. A lower power unit would likely short out much more often. But the more powerful unit can be deadly to small animals such as racoons, oppossums, squirrel, and cats and small dogs.

Homemade parabolic weather radio antenna:

NOAA Weather Radio is part of the EBS (Emergency Broadcast System) that annouces information about any emergency situations that may occur. You can purchase a radio to pick up the broadcast for under $50 at Radio Shack, Amazon, and other retailers. Broadcast stations are located in all major cities, most stations have a range of up to about 40 miles. Some stations are lower power and have much shorter range. Other factors affect range such as whether your location is in a valley or on a high elevation.

If you have trouble receiving a station because of weak signal levels, an external, you may be able to improve reception by using an add-on antenna rather than the built-in atenna of the radio. Various options are available (see You can also build your own antenna. The highest gain (producing the strongest signal) antenna is the parabolic. It's the most difficult and time-consuming to build but may be required if you live over 25 miles from a transmitter.

I made a parabolic antenna in my attic and it receives broadcasts from a station 52 miles away. The reception has a little background noise but otherwise clear and easily heard. What I did was to locate my address on a map and the location of the transmitter, then draw north/south and east/west lines from the transmitter and my location, then measure the lenghth of those lines to the point they intersect. Then draw the diagram below. That diagram fits my situation. Horizontal lines are east/west and vertical lines are north/south. As shown north is straight up. The transmitter is in the direction the parabola is aimed, to the northwest. You should be able to adaption the diagram to your situation.

The ration y/x will be equal to the ratio of the east/west distance between your home and the transmitter divided by the north/south distance between your home and the transmitter. That makes sense to me because angle A is equal to angle B, each being an angle of two proportional triangles. One of those two is the triangle two sides of which form angle A and the third side is the vertical north/south line. The second proportional triangle is the triangle with two sides forming angle B and the third side is a horizontal east/west line. The two angle can be known to be equal because two sides of one are both rotated 90 degrees to produce the other angle. The two triangle are proportional because each contain a 90 degrees angle an one other angle that is equal. From high school geometry, that makes the third angle also equal and since all angle are equal the triangles are proportional. Since they are proportional the aforementioned ratio is equal for both triangles.

Now you can lay out the antenna template in your attic. First visualize where the focus of the parabola can be located in your attic. Use a compass to visualize a north/south line running from the center of the red line (the focus of the parabola). Then visualize were an east/west line will run to the end of the parabola. I did such visualizes keeping in mind that the antenna should be as large as would fit in my attic, that produced a parabola about 12 feet across. You can increase the accuracy of the antenna's aim by adjusting the compass bearing taking into account the difference between magnetic north and true north as used by map makers. I doubt this makes much difference, but if you want to do so use Mark the point where the east/west and north/south lines intersect. Check measurements and confirm the the two distances have the correct ratio. Check to be sure there is enough height in the attic at the focal point to place a 36 inch vertical wire that will serve as the driven element of the antenna. If all is well stretch a strong cord along the red line anchored securely at each end with a nail.

Drive a nail into a ceiling joist or attic floor board at the focal point. Tie one end of another string to that nail. Run the string out at a 90 degree angle to the red line, the string extending to the parabola and looping back to its beginning at the nail. Tie that string to the string which runs along the red line, making some sort of connection that can be slid easily along the red-line cord. With the loop of string pulled taut and running 90 degrees to the red line, mark the end of the loop. That mark will be the center of the parabola. Move the end of the loop along the parabola about 16 inches keeping the loop taut and moving the sliding string connection along the red line so the string with the sliding connection maintains 90 degrees to the red line, use a carpenter's square to judge the 90 degree angle. Repeat the proceduce until the entire parabola is marked out every 16 inches.

Place wire of heavy chord uprights at each mark to be used as supports for wire mesh. I used clotheshanger wire for the uprights and chicken fence wire for the mesh. A screw or nail can be placed in roof rafters to hold the upper end of the uprights and the lower end can be stapled to floor joists or use whatever method is most appropriate for your situation. The spacing of the uprights can be adjusted so the uprights can be attached where most convenient.

Then run the chicken wire use twist ties, string, or some other method to attach the mesh to the uprights.

Then make the driven element. There are various methds that can be used. What I did was to place a 3/4 inch by 3/4 inch wood stick running vertically at the focal point. Then two pieces of 18-inch long copper wire were stapled to the upright, the two end of the copper wire place about 1/2-inch apart. A tv balum transformer's spade terminal ends were soldered to the copper wire ends. Then coax cable was run to the weather radio and connected to the radio with a coax to RCA adapter.

You should be able to find the electronic parts at Radio Shack, at many department stores, or at some hardware stores. The chicken wire can usually be found at hardware stores.

Drought ameliorization big ditch - Roof runoff and deep soil:

On my property there is a storage building 112 feet long. A lot of water pours off its roof during summer rains. A few years ago I dug a trench along the south wall of that building, made the trench 32 feet long that first year and adding another 16 feet the next years. The trench was dug 30 inches deep, 30 inches wide and about 30 inches away from the building. The soil there was hard clay with a lot of shale mixed in, for the top foot of soil. Deeper down was another 4 to 6 inches of mostly broken up shale, and below that solid shale. Before digging and backfilling the trench with topsoil, it was not a good place to grow any type of vegetable. I filled the trench with alternating layers of topsoil and organic material.

It has been a very good place to grow potatoes for the last few years, although last year the yeild was lower, partly because of dry weather but I suspect also disease and pathogens are beginning to take their toll on potatoes grown too many times in consecutive years in the same place. So this year I think I'll try some parsnips, some collards, and maybe some rutabaga in that 48 foot long area of deep topsoil. Hopefully nature will cooperate and provide frequent enough rains this summer so the building's runoff keeps them well watered, at least most of the growing season, as has been the case most of the last 4 years or so.

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