(Continued from Part 2. This concludes the article.)
In Part 1 and Part 2, we hit a few of the “How it works” or “Why it works” stuff. Proven by experience, or our family ham antenna business would have failed immediately. So, what do you have laying around the house, farm, garage – that can be turned into a high performance antenna for just listening?
In the basement / garage, Metallic stuff, old copper pipe that burst from freezing, Telephone wire, cable TV wire, Ethernet cable (4,6,8 strand stuff), Iron pipe… will work, again not as good. Old extension cords! The longer the lengths, the better! No need to strip wire or separate multi-wire cables, but, a 16awg x 100′ extension cord, whew, that’s a lot of long wire! Even a 20′ tattered Extension cord can make a very nice 20 meter dipole antenna. a 10′ extension cord can become a CB Antenna! Don’t run out and buy one, hit the rummage sales, look around for junk that can be turned into treasure!
On the farm, or barn, aluminum electric fence wire. Stainless woven stuff does work… not as good though, a roll of barbed wire… again, will work, just not as good. Old Telephone wire that once strung between poles. There is no such thing as old-useless-pipe, a television antenna mast (the pole), that won’t work as an antenna, even a flag pole!
Are you stuck living in an apartment complex, a HOA development, or a heavily-restricted community? We can get you on-the-air with stick-on copper foil, attached to a wall, window, or glass patio door. It looks like you’ve got a burglar alarm, but it’s really an antenna… and with a variable capacitor, it’s tunable! Got a big old flag pole in the front yard, say 50′ away… how about that for an antenna!? A half dozen wraps of wire around the base, connected to coax, stealthily buried in the grass back to your soon-to-be Radio Shack! Again, with a variable capacitor, salvaged from an old radio (the tuning knob thingy, that’s a variable capacitor!), it could be an excellent antenna, covering multiple bands! Metal Rain gutters / downspouts – don’t drill holes, use a little clamp to make the connection. As a last resort, a portable, collapsible Antenna can be zip-tied to a porch railing, pull it up at night, drop it down in the early hours. The same thing can be done with a thin wire, preferably Black (hardest to see from a distance), or wire that matches the color of the apartment. Really desperate? Throw a wire over the roof of the building. Or… talk to the maintenance man (I was one, once), see if he’ll allow you to put a long wire in the attic, or a full-blown antenna!
We pulled the van into an overlook, on the Blue Ridge Parkway. Set up a couple of antennas. Our daughters (teenagers) started operating, making contacts. The Park Rangers descended upon us, like ants to a picnic, “What are you doing?” Quick thinking, “We’re using a Ham Radio contest to advertise the Blue Ridge Parkway.” as one of the girls is describing the wild turkey, deer and amazing variety of birds running around. “Oh…! That’s a great idea! Just clean up and leave it like you found it.” – and left us. Nothing like a bunch of kids having fun, doing something constructive!
We have portable antennas designed and built, just for POTA Parks-on-the-air, or SOTA Summits-on-the-air, use. Some of the best ideas come from non-hams, “Say, is there anything that could be used for…?” Conversely speaking, nobody can throw ice water on project and shut it down faster than a Broadcast Engineer! Just go ahead and experiment, that’s what the entire Radio Hobby is about, experimenting and learning – not everything has been “invented” yet.
With a string and a fishing weight, a length of coax cable can be used as an 11-meter (yes, that’s CB Radio) antenna. Strip back the outer plastic-rubber-poly coating, the black stuff, about 9 feet worth. Slide back the braided shield as far as you can, and stick a pencil/pen in between the braided wires, then gradually pull the insulated center out the hole the pen/pencil made. Now you’ve got what looks like a coax with a “T” on the end, about 9′ on each side (the braided end, once stretched, will be a little longer). This is a 1/2wl dipole antenna, untuned, but I’ll work for CB (11 meters). A little bit shorter, and it’ll do 10-meter band, longer it’d do 12 meter band.
Once it’s cut, you’ve gotta live with it. However, if the end is folded back tightly (insulated or bare wire), the Resonant Frequency can be raised, tuned, etc. On one end, make a loop, run your string, fishing line, rope through the loop, a little weight on the end of the string, thrown over a tree limb – pull it up, and get-on-the-air (receiving or transmitting). If the antenna is vertical, we call that a 1/2 wave vertical (polarized). Stretch the antenna between 2 trees, and it becomes a 1/2 wave horizontal (polarized). Vertical antennas talk to other verticals the best, and vice versa. While the radio signal does ‘rotate’ over long distances, even holding your little Handi-talkie (“Bad-fang” hand-held) so the antenna is UP & vertical, does affect how well it’ll reach repeaters & other similar radios, handheld & mobiles. Verticals *like* other verticals. To adjust or completely change your coax wire antenna, shorten or lengthen it by the loops on the ends. Once it is cut, you’re done. Shrink Tubing is great for keeping the folded wire tight to the rest of the wire!
Oh, that old hay baler / rake / sickle bar mower is just rusting away. Or that silly HOA has a stupid looking old Tractor at the entrance. Think “Potential Antenna”. Coupling is your friend, Inducing a signal, in/out of any metal object, is easy, fun and can increase your signal strength! What you’ll need is a hunk of Coax, strip the antenna end back a few inches, attach an alligator clip to each conductor (center conductor & braided shield). Now you’ll need a length of any wire, say, 5′-20′ long. Here’s the simple part, wind the loose wire around the object, anywhere on it, axel on an old truck, Flag Pole, you name it, this is the experimental part, clip the wire onto the coax leads. Hook the other end up to the Radio and if it’s a ham radio, with a tuner (hit the tune button) try the 20 / 40 meter bands first, because that’s where the most activity will be. Seriously, a club in Bristol, Tennessee fired up a bridge over a river this way! I’ve livened up a Flag Pole in downtown Roanoke during a Family Day event – we had a great time! (and the kids learned all about mutual inductance, transformers, etc). What you’ve created is a Transformer, with wire wrapped around a ‘metal core’, the signal is ‘Induced’ into the ‘metal core’ / flag pole, bridge, abandoned truck, etc. It works in reverse too, your reception also improves.
Forget the line-of-sight nonsense for the ham bands. We made dozens of contacts mobile, while in a Granite Canyon, and at the Music Center on the Blue Ridge Parkway! No need to be on the top-of-the-world to hear and talk to the world. Really interesting, in both cases, in a canyon or a bowl of surrounding hills – all of our portable antennas performed excellent, with less ‘noise’ and static interference. The main drawback to a high elevation is … you hear everything unwanted. Another interesting occurrence, while cruising mobile (contesting on 40 meters), we passed through several downpours, so strong, the rain hitting the little Subaru was too loud. We’d get out of the rain, and signals just lit up the radio from all over the place! As we rolled down the now dry road, signals faded away. Hence, bad weather might improve your reception — just when a radio is needed the most, it performs wonderfully!
Another trick for the coax and loose wire: Add a metal stake for grounding. Not those huge 8′ ground rods, but a little 2′ wire like the utility workers use, those little flags (made of cheap, stiff wire). Clip the center conductor to the metal object, the braided shield to the little wire, and stick it in the ground a few inches. A few inches. A group of hams conducted an experiment years ago, just how deep does a grounding system (Radials) need to be? 6″ performed no better than just laying a wire on the top of the ground. Really? This brings us to a very interesting antenna, few people deploy, but really has a very long range.
A Beverage Antenna takes just a little preparation ahead of time, and a whole lot of insulated wire. Hundreds of feet… mine are 880′ of wire, which are wound up on a roll / bobbin. Each end of the wire gets a 50 ohm resistor with a little bit of wire beyond that, put an alligator clip on each end. You’ll also need 2 stiff wires for grounding. This works because the radio waves travel *slower* through the ground, than through the air, and the same radio waves travel faster down a copper wire. Velocity Factor… just how fast is that wire? n. A typical 50 ohm coax varies from .52 to .84 VLF – higher the VLF, the faster the Radio Wave moves through the wires/coax.
Anytime power moves, it can be ‘tapped’ between two points. Taking advantage of the slower ground and faster wire – we ‘aim’ our Beverage antenna towards… Europe! Stick a stake/wire in the ground on each end, and hook up the Coax back side to the wire and ground stake. We’re gonna induce a very small signal into the wire because of the VLF. This signal will be weak, but really, really clear. Lots of atmospheric static, thunderstorms, etc? A Beverage Antenna is a great listening Antenna.
Speaking of Loops, there’s an interesting antenna, it transmits/receives bi-directionally, front & back, with deep NULLS on both sides. Again, the broadest exposure of wire is where the signal is strongest. Taking that loose wire, a string & fishing weight (say..2oz on a 30′ of string), sling it over a tree branch – a branch that’s got a CLEAR opening below it. Elevation does not matter, just so it’s off the ground enough to move it around. We attach the coax to the wire loop we’ve hung from the tree – a big loop, and open it up, like a Triangle or Diamond. Where the Coax attaches, on one of the sides of the antenna. A tuner might be needed, but time to get-on-the-air! If you don’t like what you hear, then physically turn the wire loop (it’s hanging off the tree), 60-90 degrees. Now the antenna is oriented in a different direction. Changing the overall shape of the Antenna will affect reception (you can transmit on these antennas!) The rule of thumb on Loop antennas, enclose as much area within the loop as possible, open it up!
So, the farmer next door has Irrigation tubing, and darn it, some of it just leaking so much, he’s ready to scrap it. Can you imagine what a 40′ x 3″ piece of super light weight Aluminum pipe can do as an antenna? I’m talking all over the world, after it was cut down to 33′ in length. Take a PVC reducing coupling / plug 4″ to 2″, about 2′ of 2″ PVC which will be used to insulate the base of the antenna from the ground. Rebar, or old fence post, pound it into the ground, till 2′ is left exposed… 4′ post is fine. Slip the Aluminum pipe over the PVC insulator, slide it all over the rebar. These irrigation pipes are so light that one person can easily handle a 33′ chunk of it. Attach the center conductor to the Aluminum pipe, the braided coax will both attach to the Rebar, and 4 or more ‘Radials’.
Radials are used to improve bad ground. Radials are the other half of a Ground Plane antenna. The length *can* be random, but, if cut just slightly longer than the vertical part, they often perform best.
You’ve got a CB, needs a ground plane antenna, big time. Do you just happen to have an old Aluminum television antenna mast, steel pipe or Copper pipe? Lo, and behold, it’s 9 1/2 ft long too! Figure out a way to insulate that pipe from the ground, stick a wooden Dowel into it, sharpen the end and shove it into the ground. Those old 10′ Ethernet cables? Yeah, there’s your Radials! Strip the outside insulation off, at the base of the pipe spread the 4 pairs of wires out, 90 degrees from each other (or all in one direction, if that’s the only direction you wish to talk). Hook the center conductor to the vertical pipe, the braided shield to the ‘Radials’ made from the Ethernet cable. If the CB has a tuner, you’re ready to go. If no tuner, then start cutting pipe until the SWR looks good. Don’t throw away the cut-offs, make a mistake and cut too much, just slit the end of either pipe and stick it back together. Use a hose clamp to lock it in place.
The last antenna that I’ll mention is a different kind of Beverage Antenna. Save those aluminum cans. Make a hole in the bottom of each one. Feed a bungie cord through the cans, pull it snug, and tie a knot on the ends to keep the cans touching each other. Do the same for the Radials, at least one radial is needed. Clip the Coax onto the cans. if hanging off a tree, it’s a Vertical, feed a rope through all the cans, suspend the whole mess, and it’s a Horizontal Dipole. Yes… it does work. That’s what makes ham Radio fun, experimenting with sometimes crazy ideas.
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