For friends and beer or … how to make an antenna for all over the air TV
Photo 1. This is the general view of the antenna that should be obtained, without any additional embellishments. Many TV viewers (not talking about cable) have faced the problem of “catching” one or another program, but not and all from the same position and with the same antenna.
So how does the whole story begin.
In the beginning it was beer…
It started like all good things – word for word at the table!
I have a friend who is called Anton, LZ3AI, or when he goes to work – something else. So he took a scheme from some wise men, realized a similar antenna (but not particularly suitable for the current television broadcast) and offered it to a neighbor who follows all the series about Ronaldo, Rivaldo and the suffering Maria.
He offered her this antenna, because they cut the cable of the grandmother and the characters from the series were left without empathy.
However, when the grandmother saw the antenna, she said that she would not put such rolled cans of canned tomatoes on the terrace, even though they “caught” everything. I set about recalculating the antenna and the corresponding attempts to achieve what you will read next.
If you tap on the photos (but not with a hammer, but with the mouse), they will enlarge so that you can view them calmly. Then you close the newly appeared window to continue with the fascinating reading.
I don’t want people to be left with the belief that this antenna was born “just like that” and exactly this size of the shoulders was established only by calculations. It was a six-month long trial process on already empty beer cans that gave an answer to the question of how long they should be – exactly 9 cm, not 13, 12, 10 or 8 cm. Anyone who wishes can continue the process and establish other lengths , but the goal is still to receive all broadcast TV in very good quality.
Limitations
So that colleagues on the “wire” are not left with the doubt that I have established the propagation of radio waves and the ways of their reception, I am obliged to introduce the following restrictive postulates:</p >
1. Nothing new under the sun after 1888-1900, in terms of research material. See Hertz, Popov, Marconi. Well, yes, they did not deal with microwaves…
2. I have “laid down” the ideologies and realizations of wiser people than me, who worked and are working within a radius of 3 kilometers from the wheel on the boulevard that leads to Plovdiv and Burgas (why is it the Tsarigradskoe highway and not the California highway? With a sufficiently good reinforcement it can be used there too, yes! Some heroes even try it as an option from time to time. Well, they make sacrifices… but these are the risks of life inclusion.
3. What you will read further about the antenna and its realization can be said and written by 1/8 of the Bulgarian population (In my wife’s opinion!).
For enthusiasts who don’t want to rotate room antennas and change arm lengths or unfurl masts like sailboats with corresponding massive “real” antennas, try Turkish “satellites” ” etc. gravity irons, I offer the following recipe (as well as an opportunity to shine in front of the fairies, whatever that means!). We start with a preparatory part and procurement of materials for the antenna.
So, sit down with a friend or neighbor for a “brief production meeting” and drink a beer from an aluminum can. We need two boxes. If the person standing opposite also needs an antenna, just repeat the operation. The appetizer – according to the season. So far we are only talking about preparatory operations, so beer can be overdone. Leave the work for tomorrow!
The philosophy of the antenna is as follows: dipole 2 x λ/4 volume vibrator with approximate resonance frequency f res. 620-630 MHz, the band of which is wide enough and covers frequencies from 500 to 750 MHz. The bulk vibrator has better gain than the thin wire, but it’s still multiple vibrators. Those who have touched such material know or must have experienced the strong frequency dependence of directional antennas of relatively thin material (λ/d element. >300 and up). So this will basically be a decimeter antenna. And for the metro Channel 1 (for the different broadcast areas 210-220 MHz) – answer below!
Antenna behavior in different regions of the country:
1. In the Ovcha Kupel area (Sofia) the following programs are watched from the Kopitoto tower with very good to excellent quality of perception – Channel 1, BTV, Nova, 7 dni, GTV, CTN and Euro News, which, however, is not broadcast 24 hours hours. Pernicans can benefit from exactly the same scheme.
2. If you are “dead end” and only the roof can see the Hoof – experience has shown that with a 35-meter (hey, that’s from the first to the roof of the ninth floor) 75Ω coaxial line and a TV “FUNAI” 14″, year of manufacture 1995 (as my son), did a great job with the reception. The attempt was made in the Mladost region.
3. From the Ovcha kupel region with a TV tuned to the broadcasting frequencies from Mount Botev (the distance is about 140 km) the following was received – BTV with excellent quality, and Ani Salic from Mityo Krika can easily be distinguished on the first program. Just kidding, of course, the quality is only slightly worse, and if you wear dark glasses, you might not notice a difference at all!
4. From the area of the village of Gorni Dabnik (83 km from Botev peak) on the frequencies broadcast from the top, the first and second programs are excellent. On top of that, the antenna caught Nova TV (up to that point it was not received at all), which broadcasts with 10 W from the town of Dolni Dabnik, about 10 km from the village and the route is relatively closed. On top of that, the natural curvature of the Earth at 10 km is 2 meters overhang. Someone will say – come on, how much is two meters?! And her from two meters away… …admire a chick, right?! Two meters is two meters.
Table 1. Elevations between two points on the surface of the globe to help people only by craft (to make and operate the antenna not relevant).
| Distance [ km ] | Height of chord [ m ] |
| 10 | 2 |
| 20 | 7,8 |
| 30 | 17.6 |
| 40 | 31 |
| 50 | 49.7 |
| 60 | 70 |
| 70 | 96 |
| 80 | 125 |
| 90 | 159 |
| 100 | 196 |
| 110 | 237 |
| 120 | 282.5 |
| 130 | 331 |
| 140 | 384 |
| 150 | 442 |
| 160 | 502 |
| 170 | 569 |
| 180 | 635 |
| 190 | 708 |
| 200 | 784.5 |
| 250 | 1226 |
| 300 | 1765.5 |
| 350 | 2403 |
| 400 | 3139 |
| 500 | 4903 |
| 600 | 7061 |
In conclusion of this part, it can be said that what is proposed can replace the big rotten antennas. With relative or good visibility of the transmitter, the 2λ elevation above the ground (3 meters at least) can be neglected and the antenna stuck in a pot in the room. Otherwise, it can be carried out as an external one, but it must be wrapped with one or two plastic bags, tightened around the stick under the arms of the antenna and cut off the excess part of the bag. Then it takes the form of a small compact package and acquires a completely alien appearance. The purpose of the operation is to protect the coaxial line from running and not to see snowfall even in the middle of summer.
The beer has already been tested
Beer is the test, right? Then let’s go step by step to implementation. Now you can pour yourself a brandy, because peace of mind is necessary!
Necessary materials
Materials needed for crafting at the time of sitting:
- 2 pcs. already empty beer cans;
- 2 pcs. screws 15 mm hex with corresponding nuts and 4 pcs. washers for them;
- a chamois stick with a section of 15/15 or 20/20 mm or a combination of the dimensions, the length is up to you;
- a device or an invented way to drill the bottoms of the boxes with Ø 6-6.5 mm and the stick with Ø 5-5.5 mm;
- device for cutting the thin film of the boxes;
- a short sharp inflexible blade for digging the feeder a little into the stick – as you wish.
Crafting
1. The empty boxes are sized at a height of 90 mm from the base on which they stand (or sit). The easiest way to do this is to cut a strip of paper of this width to wrap around the box and outline. Base – again the table. The cutting can be done with a thin sharp knife or even better with your wife’s fabric scissors (it’s nice that she can’t see it). The cut should be made about 0.5-1 cm above this 9 cm, so that you can use pliers or tweezers to bend the part to size and get a double edge (see the photo). You may not do this procedure and cut directly to 90mm, but the chance of cutting yourself badly between your fingers is high (element of tripping and personal experience!).
2. You drill the bottom of the already cut box with Ø 6-6.5 mm (preferably with a tendency towards the center) and insert the screw with a folded washer from the inside. On the thread protruding from the bottom, you put a washer and a nut, meanwhile supporting the screw from below with the screwdriver. You tighten brutally, because then this screw will also cut the hole in the stick.
3. You drill the stick (not lengthwise!) with Ø 5-5.5mm in such a place where you decided to screw the already made arms of the antenna. You take one shoulder and cut the punched hole on both sides. If you drilled with Ø 5.5 mm it will be looser, but the material of the feeder compacts it. No worries!
4. If you dig a little in the stick as a bed for the feeder, for the line and braid, fasten the feeder to the stick with tape or another tape – the situation becomes even better.
5. Insert some of the stripped braid and wire (about 3-4mm) into the cut holes on the stick and screw the antenna arms.
6. If you want, you can also use double-folded household foil (from your wife’s) to close the large openings of the boxes by attaching it with tape or something else sticky. The antenna works a little better. If you wish, you can cover the finished arms with cabinet foil that imitates wood.
The visual effect is striking.
If your wife boils you while cutting with her scissors, the effect is downright amazing!
7. The antenna can be attached to whatever stakes you want or simply put in place of the old one. If you didn’t have enough beer from the cans and you continued with two-liter bottles, you can use such a bottle for a stand – you remove the cap and stick the stick with the antenna in its place (of course, the bottle is no longer full of beer, but of water – it weighs on the spot).
Exploitation
So what are you waiting for, try it now!
Concluding remarks of the author
Coca-Cola and Fanta cans have the same diameter, but it is not recommended to make them from such material. Don’t be fooled! Until now, I have never seen a wedding, baptism or graduation party done with non-alcoholic. If you’re not allowed beer, however, due to some visible curvature of the silhouette or other medical prohibitions, try a can of Fanta or another lemonade. The effect is certainly not the same.
Men know why!
