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:
- Cut a length of wire or tubing to the desired loop size.
- Form the loop into the desired shape.
- Connect the loop to the amplifier.
- 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.