Today radio thoroughbred meet difficult. The device is of the components of the phone, radio, Music Player, TV, more PC board. Each case will approach the standard antenna reception area 100 MHz signal (FM-location range). The main thing to know how to connect an external element. Found out - time to think how to make the antenna to the radio with his own hands. Variant is - intentionally resonant frequency is aimed at favorite channel to obtain the gain of the gain.
Internet video spared instead smartphone antenna adopts a piece of bare wire soldered to the socket. Divo - radio caught! No wonder. In broadcasting using vertical linear polarization, the wire is capable of arbitrary length to amplify the signal. Textbooks radio shows - can achieve results higher if multiple quarter wave size:
- Equal to the wavelength.
- Half wavelength.
- Quarter wavelength.
There are other options, some hams claim that the best reception is obtained when the length of the receiving antenna of 5/8 wavelength. Today, this shall not stop. Each of the above devices is characterized by the internal resistance, the value possibly equal to the impedance of the cable, the receiver:
- Dipole antenna - 300 ohms.
- A half-wave dipole - 73.5 ohms.
- The quarter - 37 ohms.
Note. It is ideal structures of resistance. Practically difficult to achieve the ideal. approval is required.
Consistent with what has been said allocated dozen nominal standard cables, often encounter RK - 75, RK - 50. The latter has the largest circulation among the connected equipment. It is important to use a coax, used the appropriate device type. On older TVs inputs specially signed in ohms. VHF uses cable RK - 50. Therefore, loss caused by reflection of the signal line, the lowest.
Internet bypassed circuit half-wave dipole length of 75 cm each side. The receiving device serves a range of VHF (FM), accommodating a lot of radio stations. Let's explain pretty:
- dipole length is one-half wavelength;
- each arm of a vibrator equals a quarter wavelength.
Total obtain device is configured to broadcast frequency of 100 MHz, a quarter wavelength is 75 cm. Resistance radiation design equals 73.5 ohms, so the antenna for the radio with his own hands made out of a piece of cable RK - 75:
- To form one dipole arm remove the outer insulation portion of a length of 75 cm. the braided shield is left untouched.
- After a gut-wrenching copper mesh stockings, pulling down, straightening up to 75 cm. Formed a second arm of the dipole. If the screen is difficult to pull over the insulation, take a piece of copper tube of 75 cm length, string. The braid is cut off, adding to the contents of the bin.
- The copper tube is soldered accurately to the screen, the device is ready. Coordinate with the cable does not need both impedance of 75 ohms. modern receiver may have a very different impedance. More read in the specifications listed passport.
- Installation is carried out on the mast. Above - better, but! Passive antenna for the radio, the hands made of cable piece, greatly reduces the signal strength. Discuss later how to solder band amplifier, equipped with an impermeable casing to hang near the antenna. Sensible course project topic moderate student preparedness university radio direction. Today, the issue is postponed.
Quarter wave vibrator broadcast reception
IPhone requires a resistance of 50 ohms. We'll have to make a quarter-wave oscillator to the frequency of cable RK - 50. Theoretically, it is impossible, part of the power is lost, but try:
- With cable RA - sheath 50 removed, the isolation length 37.5 cm.
- The second end equip docking connector design to fit solder contacts.
Homemade antenna for radio ready! You make antenna FM-band digital television. The length of the cut braid Insulation determined frequency channel. It does not need a predominantly matching device. For catching a vertically hanging wire broadcasting; television - horizontally. Predetermined type of linearly polarized waves.
Full-sized vibrator broadcast reception
Field, forest, look for a good piece of cable reception is important for the city. What to do. We make full wave dipole vibrator resistance 300 ohms, matching device 75 Ohms:
- Remove the cable insulation RK - 75 length of 1.5 meters, braided reserve.
- Gently contract the screen down a further 1.5 meters. The metal tube instead be unfit decision, try to use foil tape. The antenna for the radio with his own hands is needed at the time of the campaign. The main thing is that the screen was cut over 1.5 meters.
- We make a matching device that is connected after the "stocking" (middle vibrator). Cut the cable from the antenna, we undertake to work.
- U-knee should be 1.5 meter (one half wavelength), wherein a central point to bend in half and tie string. Wiring diagram is as follows:
- Stockings put on one end of the U-knee.
- In place of the beginning of the stocking cut through the insulation to the conductor. Vein simultaneously planted on the other end of the U-knee and output wire resistance of 75 ohms.
- Screens knee, output cable is grounded. But! Not our makeshift antenna.
Vibrator itself is hung on the tree trunk, facing the direction of broadcasting (the thickness of the wood introduced damping catchers choosing the wrong orientation). Suitable for grounding Barbecue skewer stuck under a tree. Receiver hang side by side. The antenna for the radio with their hands after using the wound for use next time.
Note that the wave impedance matching device is equal to the impedance of the antenna. Ideal - 300 ohms. The cable lies in store, but expensive (forest, mountains) are unlikely to find.
For a half-wave dipole split (hem in the middle) connection to the U-knee output cable, it is necessary to conduct a three-quarter-length, not at the end. In the right place matching element cuts through touching wires, connecting the output cable is held RK - 75. can make itself U-knee, using the specified grade coaxial cable.
The first design (previous subsection) appears simpler to use vibrators quarter-split is not accepted. But the knee can be made by breaking cable RK - 50 (like an antenna). Skillful hands - an integral part of the fan to save. Introduce process design gainful employment. It will go more fun.
If found ready antenna for TV
Some TV antennas are also intended for radio reception. We can assume that lucky. In this case, the amateur radio antenna with your hands made as simple as possible. You must rewire the connector to the receiver on the one you want. As a result, the reception should improve significantly.
Antenna for FM and VHF bands
These ranges overlap, but in practice it is customary to distinguish the old Soviet and new European. The first lies below 74 MHz, the second - above 88 MHz. Antenna for these bands can be made from ordinary elementary foil. The dimensions will be different. You will need a small square flat board. Let's start with the FM-range, then gradually move on VHF.
Take a plate size of 15x15 cm. Need foil 13x13 cm. Allowed solder from two or more pieces of a smaller size. Form the desired strip shape of 15 mm in thickness. And what - I'll tell:
- In taking the foil is cut in the middle of the square hole 10 cm. Frame received exactly 15 mm thick, from which the glue strips.
- In the middle of the bottom is cut out a thin piece, 3 mm wide.
- Now the figure is stuck on board for safety.
Connecting cable RK - 50 as follows:
- Solder the center conductor homemade antenna for radio at the bottom right. In the middle of the strip in front of the right edge of the cut part.
- The screen also soldered in the middle to the left by 25 mm.
Sizes vary to VHF:
- Dice Party - 18 cm.
- Side of the outer square - 15.5 cm.
- Thickness - 18 mm.
- The distance between the contacts 4 cm.
Our story is over how to make the antenna to the radio with their hands out of scrap materials. Some designs are good for the garden, on the nature, others will be useful in transport. And for handheld use a piece of wire soldered to the socket. This is also mentioned in passing. The owners of expensive televisions, bypassing the party portal VashTehnik buy an expensive equipment and forget: self-made design saves a lot of time, effort, body weight ...
We would like to remind - themed articles of low quality, are not distinguished professionalism. To configure real antennas need special equipment. Each unit will make the reception better. Newly made constructive may be cited as an antenna for the radio, made with his own hands.
Note. To configure the product visit the forums. Radio amateurs are eager to share his secrets. Prompt SWR measuring methods, hardware, a result value.