ANTENTOP- 01- 2018 # 022

Two Simple Low Pass Filters for 145- MHz Band

However, ever recently in our crazy tech epoch it is not everyone has a Spectrum Analyzer in own home or access to such device at some place. Without a Spectrum Analyzer it is possible to tune the Low Pass Filter for 145- MHz Band to minimum SWR but hard to adjust the internal rejection filters. In this case it is possible to do a compromise variant of such filter-without internal rejection filters.

Schematic of a simple Low Pass Filter for 145- MHz Band without internal rejection filters is shown in Figure 8.

The filter made on a piece of two sided PCB. Capacitors of the filter are created on the board. Figure 9 shows design of the filter. Figure 10 shows view of the filter. Figure 11 shows layout of the capacitors. The capacitors made on a PCB that has thickness in 1.5- mm. However different PCBs depend on the stuff and the thickness may have another capacity per square centimeter. It is very useful to find the capacity per square centimeter and re-calculate (if it should be done) the sizes of the capacitors before the capacitors would be made.

Figure 8 Schematic of a simple Low Pass Filter for 145- MHz Band (without internal rejection filters)

Figure 9 Design of the simple Low Pass Filter for 145- MHz Band (without internal rejection filters)

Figure 10 View of the simple Low Pass Filter for 145- MHz Band (without internal rejection filters)

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