Greeting Everyone!!!!!!!!!!!!!
We built a L.P.F. (Low Pass Filter) design published in 1987 ARRL hand-book in chapter 2 (2-44).
The circuit performs very well in 7Mhz freqency. The ARRL Hand-book has given the test chart as below:
|
Filter No.
|
Fco
|
3 dB
|
20 dB
|
40 dB
|
Max. SWR
|
C1, C5 (pF)
|
L2, L4 (uH)
|
C3
(pF)
|
|
87
|
7.54MHz
|
8.61
|
11.5
|
17.0
|
1.327
|
470
|
1.45
|
820
|
This filter works as it is with out any changes and modifications.
Below we have show the tested circuit without any modifications from the original circuit which is also show below.
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