In the market there are a variety of antennas for television. The most popular according to my criteria are: UDA-YAGIS, Dipole, Dipole with reflectors, Patch and Logarithmic antennas. Depending on the conditions, the distance from the transmitting antennas and the frequency that you want to tune the users usually choose between some of the above. The aesthetic and bulky appearance of the antennas also tend to influence purchasing decisions and manufacturers know this. That is why more and more are appreciated, for example, yagi antennas full of guiding elements, although not separated at the optimum distance and large reflectors in some cases unnecessary. Luckily the antennas of TV reception cannot damage the TV (unless they conduct some electric shock with which you would be condemned). Since the TV do not transmit, but receive signals, there is no risk of damaging the device due to excess standing waves and overheating of the amplifier stages. In this INSTRUCTABLE I will show how to make a UHF antenna for the TV band. It is not cumbersome, but it has given me very good results.
Step 1: Materials You Need
• Solid copper wire 1m long and 2mm to 4mm in diameter
• Wooden base and lid (I explain how to do it)
• Coaxial cable 75 ohm RG-59, RG6 or compatible, 1m long or greater according to your needs
• F connector for the selected coaxial cable
Step 2: Antenna Design
The proposed antenna has been designed using the 4nec2 program. The results obtained with the simulator and in practice show that it has very good performance in the UHF band (frequencies 473Mhz-701Mhz) and with the best results in the 617Mhz. I attach the * .nec file for those interested in their analysis.
Step 3: Construction of the Antenna
Bend the wire. The final result of having folded the 1m wire is shown in the image. For this, it is suggested to start from the center and complete the folds until completing the required form. The center of the wire can be obtained by balance (the density of the wire must be the same, I suppose).
Build a coil of approximately 10 turns on a piece of wire of the same diameter as the antenna. Leave one of its ends elongated, then we will see why. It will not be used as an inductor, only to join the last ends of the wire after making the bends so the number of turns can vary if you wish.
Slide the final ends of the antenna inside the built coil and solder the whole
Step 4: Construction of the Base
You can design any type of base that supports the antenna and facilitate the connections with the coaxial cable as long as it is a dielectric material (plastics, woods, ceramics etc ...) The images show how I design mine.I enclose a file in sketchup from where you could extract details of your measurement.
Step 5: Assembly of the Parts
• Place the antenna on the wooden base
• Cut the length of coaxial cable you want and place the connector F on one of its ends
• Prepare the other end of the coaxial cable to attach it to the copper antenna as shown in the image
• Attach the outer mesh of the coaxial cable to the remainder of the junction coil (remember?) And the center conductor of the coaxial cable to the other center of the copper wire antenna.
• Make tin solders when necessary.
• Fill the entire cavity with some epoxy glue and replace the cap. Maybe you should hold it in some way until everything is dry.
Note: It is extremely necessary to verify that the joints previously made do not join together.
Step 6: Possible Improvements and Implementation.
The wooden base that has been shown in the photos has not been varnished, it has only been primed with a sealer. Perhaps it would result in a more beautiful antenna if it was properly sanded and varnished.
Copper tends to darken over time, try to coat it with varnish as well and protect it.
In some cases, you should connect it outdoors because the signal is very weak inside for which it would be convenient to design some base in another material for this purpose.
It only remains to connect it to your TV and scan for channels to enjoy digital terrestrial television.
Step 7: Final Notes
I have already made several and plan to give them to my relatives. Get wet and do your own too. Remember to contribute your ideas and improvements to the rest of the community.
All materials and tools used in this project can be purchased through Ebay. If you click on the following link and make a purchase you will be contributing to get a small commission. Thank you and keep up with my next projects.
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