AOR ABF-128 SMA airband filter

Do you regularly listen to the VHF aviation band and find that strong signals outside the Airband interfere with your scanner's reception? The AOR ABF-128-SMA is a specialized reception filter for frequencies between 108 and 136 MHz. The filter is placed in the antenna signal line and helps suppress strong, unwanted signals outside this frequency range before they reach the receiver.

The result? Your AOR scanner or other compatible scanner or broadband receiver can better handle strong interfering signals that could otherwise negatively affect reception on the airband.

Thanks to its SMA connection, the compact Airband filter can be used with many scanners and broadband receivers that have a suitable SMA antenna connection. The filter can be used in combination with an external antenna or directly under the antenna of a suitable handheld scanner.

What does the AOR ABF-128-SMA Airband filter do?

A scanner often receives a much larger frequency range than just the aviation band. While this is convenient, strong signals outside the frequency range you are currently interested in can sometimes overload the receiver.

The AOR ABF-128-SMA addresses this problem by adding extra selectivity between the antenna and receiver.

The filter allows the VHF Airband frequency range between 108 and 136 MHz to pass through and significantly reduces strong signals outside this range. This means fewer unwanted signals reach the receiver's first mixer stage. According to AOR, this can lead to less interference and improved reception when strong signals would otherwise overload the receiver.

For the enthusiastic Airband listener, such a relatively small component can therefore make a noticeable difference.

Specially developed for the VHF Airband

The ABF-128-SMA is a bandpass filter for the Airband. Instead of transmitting the full reception range of your antenna unfiltered to the scanner, the filter focuses on the frequency range of 108 to 136 MHz.

According to AOR, the suppression outside the desired frequency range is typically 40 dB below 87 MHz and 40 dB above 170 MHz.

This is particularly interesting in environments where strong signals outside the aviation band are present and negatively affect the performance of a broadband receiver.

Not an amplifier, but a filter

This distinction is important: the AOR ABF-128-SMA is not an antenna amplifier.

The filter does not make weak signals stronger. The benefit lies in suppressing unwanted strong signals outside the desired frequency range. This means the receiver has to process fewer unwanted RF signals, and reception can improve in situations with strong interference.

As with any filter incorporated into the antenna signal line, there is also some attenuation of the desired signal. For the ABF-128-SMA, a loss of approximately 4 dB is specified within the passband. According to the product information, the filter has a VSWR of 2:1 within the band.

So you trade limited signal attenuation for significantly more filtering of strong signals outside the desired Airband.

Easy connection via SMA

The AOR ABF-128-SMA is equipped with SMA connectors. There is an SMA-Female connection on the top and an SMA-Male connection on the other side.

This allows the filter to be placed, for example, directly between the scanner and the antenna on a compatible handheld scanner.

Are you using an external antenna? In that case, the filter can also be incorporated into the antenna signal line, provided your installation's connections are suitable for this.

Although the filter is from AOR, according to the product information, it is not exclusively intended for an AOR scanner. The ABF-128-SMA can also be used with many scanners and broadband receivers from other brands that have a suitable SMA antenna connection.

Key features

• Special Airband filter: bandpass filter for reception between 108 and 136 MHz.
  
• Suppresses unwanted signals: typically approximately 40 dB below 87 MHz and above 170 MHz.
  
• SMA connection: SMA female on the top and SMA male on the other side.
  
• For scanners and broadband receivers: suitable for compatible receivers with SMA antenna connection, regardless of brand.
  
• Compact solution: suitable for use with an external antenna or directly under the antenna of a compatible handheld scanner.

When is an Airband filter interesting?

Not every reception location suffers equally from strong signals outside the aviation band. In a relatively quiet RF location, the need for extra filtering may therefore be limited.

However, are you listening in an environment with strong signals that can overload your scanner or broadband receiver? Then extra filtering can be particularly useful.

The AOR ABF-128-SMA does not prevent such signals from being received by your antenna, but it ensures that many unwanted signals are greatly attenuated before they reach the receiver.

This makes this AOR Airband filter an interesting addition for the serious aviation listener who wants to get more out of their existing scanner and antenna installation.

Are you bothered by strong interfering signals when listening to the VHF aviation band? Add the AOR ABF-128-SMA to your antenna signal line and give your scanner extra selectivity for the frequency range of 108 to 136 MHz.