Hallo NG,

from my visit of the ham radio in Friedrichshaven, last weekend,
I get some c-mac crystal filters in the hope I could use them for cw.
The filter is labeled as
CMAC EP089.3910
1.44MHz-BandP, B:150Hz
768JAB
Date-Code: 9804 No.: 28654

When trying to match it with 600, 800, 1000 Ohm
by a LC-network (calculated by RF-Sim 99)
(R=600,L=18u,C=618p; R=800,L=21u,C=535p; R=1000,L=24u,C=480p)
I get a Bandwidth of about 300Hz/6dB and the 50-Ohm output
of my HP-Synthesizer goes down to 1/4th of the 10mV I supply
to the Filter and not to 5mV like expected.
Looks like the filter impedance was transformed to about 16 Ohm.
Was my assumption that the filter impedance lies between 600
and 1000 ohm wrong (looks like it was ;-).
When looking at www.cmac.com I was not to able to find any info's
on that certain filter.

Could someone of You provide me the right filter data for the proper
matching.

Many thanks in advance

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Markus Wolfgart
DL8MBY

DLR

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