> At this weekend's Rochester (NH) hamfair, I found what appears to be a
> spanking new four-pole Ten-Tec IF ladder filter. Can anyone on the thread
> please help me identify it?
>
> The glass-epoxy board measures 1-inch x 2-3/8-inches in size. It has four
> pins, one at each corner, and four crystals, three of which are not engraved
> or stamped with any numbers. One crystal is stamped "8310" on top in black
> ink. The two outermost crystals (at the ends of the filter) have blue paint
> dots in their sides. The innermost crystals have red paint spots.
>
> The board is etched to accommodate eight crystals, but only has four (the
> pads are jumpered). The existing rocks have their cases soldered together.
> There is a number 684? etched onto the bottom of the board, but the last
> digit is filled with solder and isn't readable (if it is a digit)!
>
> Each input pin is shunted by a 51 pF capacitor to ground. The value of the
> caps between the 1st and second xtals, and between the 3rd and 4th is 100 pF
> (also to ground). The value of the cap in the "middle" of the ladder is 130
> pF.
>
> Does anyone know what the termination impedance is? What the BW is? Where it
> was originally used (In a Corsair or an Argonaut 509 perhaps)? What the IF
> frequency is?
>
> Thanks! Vy 73, AI2Q, Alex
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