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VHF Air Band
RF Filter


Replaced by

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Discontinued RF Filters  

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The AOR ABF125 is a receive bandpass filter especially designed for serious VHF airband listeners. This filter improves the strong signal handling characteristics of scanners and wideband receivers for VHF commercial Airband listening. The ABF125 is suitable for connection to most scanners and wideband receivers on the market, regardless of brand. The addition of this filter to the antenna's signal path provides additional selectivity which enables the receiver's circuitry to better cope with strong interfering signals that can leak into the 108-136 MHz VHF air band.

The ABF125 provides additional selectivity to any receiver's front end by reducing a multitude of unwanted strong signals from reaching and saturating the receiver's first mixer stage. This results is less interference and improved reception. The ABF125 offers excellent out-of-band attenuation typically of 25 dB from 0.3 to 75 MHz and 20 dB from 190 to 400 MHz. This makes the ABF125 suitable for connection to both external antennas and for connection directly under the whip aerial of a hand-held receiver. A BNC socket (female) is fitted to the top of the ABF125 and a BNC plug (male) to the other making connection to an aerial easy and straight forward.

The ABF125 is not an amplifier so will not boost signals, however the additional selectivity offered can significantly improve reception in many situations by removing unwanted strong signals which may overload the receiver and reduce it's effectiveness. When any connection is fitted to the aerial signal path some reduction of signal is resulted (attenuation) however the ABF125 in band attenuation level is very small due to the excellent in band V.S.W.R. of 2:1 resulting in a loss of only about 4 dB.

Note:  Remember to remove the ABF125 from the antenna input when monitoring signals other than VHF Airband or signal strength will be dramatically reduced.

Bandpass Coverage 108 to 136 MHz
Impedance 50 ohm
Attenuation In Band 4 dB
Attenuation 0.3 ~ 75 MHz 25 dB min.
Attenuation 190 ~ 400 MHz 20 dB min.
Size 2.9 inches (74 mm.)

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