Antenna Handbook

Receiver for Fiber-Optic IR Extender



There are various types of remote-control extenders. Many of them use an electrical or electromagnetic link to carry the signal from one room to the next. Here we use a fibre-optic cable. The advantage of this is that the thin fibre-optic cable is easier to hide than a 75-Q coaxial cable, for example. An optical link also does not generate any additional radiation or broadcast interference signals to the surroundings. We use Toslink modules for connecting the receiver to the transmitter. This is not the cheapest solution, but it does keep everything compact. You can use a few metres of inexpensive plastic fibreoptic cable, instead of standard optical cable for interconnecting digital audio equipment. The circuit has been tested using ten metres of inexpensive plastic fibre-optic cable between the receiver and the transmitter (which is described elsewhere in this issue).

The circuit is simplicity itself. A standard IR receiver/demodulator (IC1, an SFH506) directly drives the Toslink transmitter IC2. We have used the RC5 frequency of 36 kHz, but other standards and frequencies could also be used. Both ICs are well decoupled, in order to keep the interference to the receiver as low as possible. Since the Toslink transmitter draws a fairly large current (around 20 mA), a small mains adapter should be used as the power source. There is a small printed circuit board layout for this circuit, which includes a standard 5-V supply with reverse polarity protection (D2). LED Dl is the power-on indicator. The supply voltage may lie between 9 and 30 V. In the absence of an IR signal, the output of IC1 is always High, and the LED in IC2 is always on. This makes it easy for the transmitter unit to detect whether the receiver unit is switched on. The PCB shown here is unfortunately not available readymade through the Publishers' Readers Services.


source : https://archive.org/details/ElektorCircuitCollections20002014/page/n13/mode/2up?view=theater


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Transmitter for Fibre-Optic IR Extender


This circuit restores the original modulation of the signal received from the remote-control unit, which was demodulated by the receiver unit at the other end of the extender (see 'Receiver for fibre-optic IR extender').

If no signal is received, the Toslink transmitter in the receiver is active, so a High level is present at the output of the Toslink receiver in this circuit. Buffer IC2a then indicates via LED Dl that the receiver unit is active. The received data are re-modulated using counter IC3, which is a 74HCT4040 since the Toslink module has a TTL output. In the idle state, IC3 is held continuously reset by IC1. The oscillator built around IC2c runs free. When the output of the Toslink receiver goes Low, the counter is allowed to count and a carrier frequency is generated. This frequency is determined by the oscillator frequency and the selected division factor. Here, as with the receiver, we assume the use of RC5 coding, so a combination has been chosen that yields exactly 36 kHz. The oscillator frequency is divided by 2 9 on pin 12 of the counter, and 18.432 MHz 2 9 = 36 kHz. The circuit board layout has a double row of contacts to allow various division factors to be selected, in order to make the circuit universal. You can thus select a suitable combination for other standards, possibly along with using a different crystal frequency. The selected output is connected to four inverters wired in parallel, which together deliver the drive current for the IR LEDs D3 and D4 (around 50 mA). A signal from the counter is also indicate that data are being transmitted, via LED D2. This has essentially the opposite function of LED Dl, which goes out when D2 is blinking. In the oscillator, capacitor C3 is used instead of the usual resistor to compensate for the delay in IC2c. As a rule, this capacitor is needed above 6 MHz. It should have the same value as C load of the crystal, or in other words 0.5C1 (where CI = C2). At lower frequencies, a lkQ to 2kQ2 resistor can be used in place of C3.


A yellow LED is used for the power-on indicator D5. The current through this LED is somewhat higher than that of the other LEDs. If you use a red high-efficiency LED instead, R5 can be increased to around 3kQ3.


The circuit draws approximately 41 mA in the idle state when the receiver is on. If the receiver is switched off, the transmitter emits light continuously, and the current consumption rises to around 67 mA.


The PCB shown here is unfortunately not available readymade through the Publishers' Readers Services.

source : https://archive.org/details/ElektorCircuitCollections20002014/page/n1/mode/2up?view=theater


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active loop antenna

 An active loop antenna is a type of loop antenna that uses a built-in amplifier to boost the signal strength. This makes it more sensitive than a passive loop antenna, but it also introduces some additional noise. Active loop antennas are typically smaller than passive loop antennas, which makes them more portable and easier to install.

Here is a illustration of a typical active loop antenna:

The antenna consists of a loop of wire or tubing, which is connected to an amplifier. The amplifier boosts the signal strength and reduces noise. The antenna is typically mounted on a tripod or other support.

Here are some images of active loop antennas:

Design Considerations

When designing an active loop antenna, there are a few key factors to consider:

  • Loop size: The size of the loop determines the frequency range of the antenna. A larger loop will have a lower resonant frequency, while a smaller loop will have a higher resonant frequency.
  • Loop shape: The shape of the loop can also affect the antenna's performance. A circular loop is the most common shape, but other shapes, such as square or triangular loops, can also be used.
  • Amplifier: The amplifier is the most important component of an active loop antenna. It should be chosen carefully to ensure that it has the appropriate gain and bandwidth.

Construction

Once you have considered the design factors, you can begin constructing your active loop antenna. The following steps provide a general overview of the construction process:

  1. Cut a length of wire or tubing to the desired loop size.
  2. Form the loop into the desired shape.
  3. Connect the loop to the amplifier.
  4. Mount the antenna on a tripod or other support.

Tuning

Once the antenna is constructed, it is important to tune it to the desired frequency range. This can be done by adjusting the length of the loop or by using a variable capacitor.

Use

Once the antenna is tuned, it can be used to receive radio signals. To do this, simply connect the antenna to a receiver. The receiver will amplify and demodulate the signal, so that it can be heard or seen.

Active loop antennas are a versatile and effective type of antenna. They can be used for a variety of applications, such as receiving shortwave and mediumwave radio signals, radio direction finding, and amateur radio.

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Conclusion

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Illustration Images

Overall, Proton VPN is a great choice for anyone who wants a secure and reliable VPN service. It offers a variety of features to protect your privacy online, and it is available for a variety of platforms.

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What is an Antenna ?

 An antenna is a device that transmits and receives electromagnetic waves. Electromagnetic waves are a form of energy that travels through space at the speed of light. They include radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays.

Antennas are used in a wide variety of applications, including:

  • Radio and television broadcasting
  • Cellular and mobile communications
  • Satellite communications
  • Radar
  • GPS
  • Wi-Fi
  • Bluetooth
  • RFID
  • Wireless security systems
  • Microwave ovens

Antennas come in many different shapes and sizes, depending on their application. Some common types of antennas include:

  • Dipole antennas: These are the simplest type of antenna, consisting of a straight wire or rod. Dipole antennas are omnidirectional, meaning they radiate and receive signals in all directions.
  • Yagi antennas: These antennas are made up of a dipole antenna plus one or more reflectors and directors. Yagi antennas are directional, meaning they radiate and receive signals in a specific direction.
  • Dish antennas: These antennas are parabolic in shape and are used to focus signals in a narrow beam. Dish antennas are often used for satellite communications and radar.
  • Omnidirectional antennas: These antennas radiate and receive signals in all directions. They are often used for indoor applications, such as Wi-Fi and Bluetooth.

Antennas work by converting electrical signals into electromagnetic waves and vice versa. When an electrical current is applied to an antenna, it creates an electromagnetic field. This field travels through space in the form of radio waves. When an electromagnetic wave hits an antenna, it induces an electrical current in the antenna. This current can then be amplified and processed by a receiver.

The design of an antenna determines its frequency range, directivity, and gain. The frequency range is the range of frequencies that the antenna can transmit and receive efficiently. The directivity is the direction in which the antenna radiates and receives signals. The gain is the measure of how well the antenna amplifies signals.

Antennas are an essential part of many modern technologies. They allow us to communicate with each other, access information, and navigate the world around us.

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How to Troubleshooting Antenna TV Reception ?

 To troubleshoot antenna TV reception, you can follow these steps:

  1. Check your connections. Make sure that the coaxial cable is securely connected to both the antenna and the TV. You may also want to try using a different coaxial cable, just in case the current one is damaged.
    Checking the connections of an antenna TVTerbuka di jendela baruwww.lifewire.com
  2. Check your antenna's placement. Make sure that the antenna is in a high location, away from obstructions such as trees, buildings, and power lines. If possible, try to point the antenna directly at the TV broadcast towers. You can use an online TV antenna locator to find out where your local broadcast towers are located.
    Checking the placement of an antenna TVTerbuka di jendela baruwww.antennasdirect.com
  3. Use an antenna amplifier. If you live in a weak signal area, using an antenna amplifier can help to boost the signal.
  4. Scan for channels. Once you have made sure that your connections are secure and your antenna is in a good location, scan for channels on your TV. This will help to identify any channels that are available in your area.
    Scanning for channels on a TVTerbuka di jendela baruwww.samsung.com
  5. Try a different antenna. If you are still having trouble getting good reception, you may want to try using a different antenna. There are many different types of antennas available, so you may need to experiment a bit to find one that works best for your location.

Here are some additional tips:

  • If you are using an amplified antenna, make sure that the amplifier is turned on and properly grounded.
  • If you are still having trouble getting good reception, try using a coaxial cable extender to connect the antenna to your TV.
  • If you are using a split-and-tap connector to split the signal from your antenna to multiple TVs, make sure that the connector is rated for the number of TVs that you are connecting.
  • If your antenna is outdoors, make sure that it is properly protected from the elements.

If you have tried all of the above and are still having trouble getting good reception, you may want to contact a professional antenna installer for assistance.

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The Best Transmitter Locator Antenna App

 


The best transmitter locator antenna app is the one that works best for your specific needs and location. However, here are a few of the most popular and highly-rated options:

  • Antenna Point (Android and iOS): This app uses your phone's GPS and compass to identify nearby TV transmitter towers. It also provides information about the distance to each tower, the azimuth, and the elevation.
  • TV Signal Finder (Android and iOS): This app is similar to Antenna Point, but it also provides additional information, such as the channel numbers and frequencies of the transmitters.
  • TV Fool (web): This website provides a detailed map of TV transmitter towers in the United States. It also allows you to enter your specific location to generate a custom report that shows the channels that you are likely to receive.

To use a transmitter locator antenna app, simply open the app and allow it to access your phone's GPS and compass. The app will then display a map of nearby TV transmitter towers. You can then zoom in and out of the map, and tap on the towers to get more information about them.

Once you have found a tower that you want to point your antenna towards, you can use the app's compass to align your antenna in the correct direction.

Here are some tips for using a transmitter locator antenna app:

  • Make sure that you have a good GPS signal. This will help the app to accurately locate your position.
  • Calibrate your phone's compass. This will help the app to provide accurate compass readings.
  • Use the app to find a tower that is in the line of sight of your antenna. If there are any obstacles between your antenna and the tower, this will reduce the signal strength.
  • Use the app to align your antenna in the correct direction. The app should provide you with an azimuth reading, which is the angle that you need to point your antenna in.
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