NVARC Ugly Filters Update #1

Last night after hours of frustration trying to get the 40m filter to work properly I decided that running capacitors in series to achieve the required value may be causing me problems.

The best I could get from the filter was an insertion loss of about 4 or 5 dB. This was robbing me of more than half my power.

So first up I removed the 1000 pF, 820 pF and 150 pF that made up a 112 pF capacitor and replaced it with a single 100 pF that I had measured at 107 pF.

Straight away I had less insertion loss. Still not great but at least I was now moving in the right direction.

So next I removed the 1500 pF, 470 pF and 220 pF that made up 136 pF and replaced it with a 100 pF with three 100 pF in series paralleled across it. Again a signal improvement.

The last change was to remove 1000 pf, 1200 pF, and two 470 pF capacitors and substitute a 100 pf with a 100 pF and a 150 pF in series paralleled across it.

Now the insertion loss is about 1dB. A much better position.



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