RF Filter
The RF filter is critical and must be correctly tuned for the transceiver to perform properly.
C16, C17, and C19 form an impedance transformation that was used to avoid using very tiny
capacitance coupling between L4 and L6.
If C13, C14, and L4 will not tune to midpoint in the 17 meter band, adjustment should be made by
adding or subtracting turns on L4.
If C20, C18, and L6 will not tune to midpoint in the 17 meter band, adjustment should be made by
adding or subtracting turns on L6.
When adjusting C14 or C18, you should find 2 rotation positions which peak the signal. This is to
insure that you are not at an extreme end of rotation and not really at a peaking point.
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