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eHam Forums => CW => Topic started by: KB2EE on November 04, 2012, 09:41:37 AM



Title: Filters made by Piezo Technology
Post by: KB2EE on November 04, 2012, 09:41:37 AM
Hi,
I have couple of crystal filters made by Piezo Technology Inc. and I would like to use them in homebrew receivers, but I don't know this filter's termination impedances.  I'm pretty sure this filter was used in a commercial/military receiver, maybe a RACAL unit, maybe some other receiver.  The receiver's schematic would reveal the impedances, so if you know what receiver used a Piezo Technology Inc. Model 1815, center freq 1750 kHz, bandwidth 500 Hz filter, let me know.  The filter is also stamped with what looks like the receiver manufacturer's in-house part number:  1920-0603.  Happy holidays to everyone, tnx, 73.....Larry  KB2EE


Title: RE: Filters made by Piezo Technology
Post by: PA0BLAH on November 04, 2012, 12:35:23 PM
put the filter with a series resistor between a 50 ohm signal generator and a load resistor. look at the pass band ripple. take carbon trimpots for the resistors, change them till passband is Okay. Measure the trimpots any you know what you ask. Above that you know the pass band loss.