The ERA BP34 filter is an 'one knob' audio filter for the radio ham and short wave listener.This model was produced in 1989 and was unlike many of it's competitors inasmuch as it used a switched capacitor audio filter . Whereas analogue active filters require critically matched components, in this system only the ratio of the components is critical.
It needs a 13.8 volt nominal supply (built in voltage regulator means it will accept 12v to 25v)
The BP34 has two fixed lower cut-off frequencies and variable upper cut off frequencies. This allows for ease of operation with continuously variable bandwidths available from one control knob.
The doyen of QRP the Rev George Dobbs G3RJV commended it highly in his review in Practical Wireless "I would commend it's use for any serious radio amateur or shortwave listener, it is a sophisticated device , works well and is simple to use....."
A full copy of this review is included , this also contains the details of cut off freqs, bandwiths and passband ripple.
The original manufacturers Operating instructions are also included.
The unit measures 134 x 54 x 123 mm including feet and weighs about 500gm Very compact and perfect for mobile working.
Payment modes Paypal, online bank transfer.
Postage UK and EEC £12
Other destinations please contact for quote
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