#243: Mini-review & test of a variable audio bandpass filter from SOTABeams

Here is a short review and test of the Laserbeam-VARI, a variable audio bandpass filter module from SOTABEAMS. This compact module is a powerful and flexible audio bandpass filter that is designed to be used primarily with amateur (ham) radio receivers to help eliminate signals & noise that are adjacent to the signals that you are trying to listen to. The filter is first evaluated on the test bench, then brought up to the radio shack and put inline with the receiver's audio path to see how effective the filter can be. Bottom-line: the filter is extremely easy to use, and very effective in helping you to pass only the portion of the audio spectrum that you select. The filter is designed to operation from about 100Hz to about 3.5kHz - so it is NOT designed for high-fidelity audio applications. It is intended to aid in the reception of communications grade audio signal, including voice and other modes like CW and digital modes. More info can be found at the following links:

Product Page:

http://www.sotabeams.co.uk/variable-bandwidth-filter-modules-ssb-cw/

Application Sheet:

http://www.sotabeams.co.uk/content/LASERBEAM-VARI.pdf

Other SOTABEAM products on their main page:

http://www.sotabeams.co.uk/

Here is the app I used on the iPad to view the audio spectrum:

http://www.oxfordwaveresearch.com/products/spectrumviewapp/