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Anatoli, RL1L
ex. (RA0C, EY9AF, RA6XPL, RA6PS, RA6PGY)
Credit Line:
Forum at www.cqham.ru
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A
Low Pass Filter is recommended to use in a Field Day operation
when several amateur radios that work at 145 and 430- MHz are
placed close to each other. In this case the third harmonic of
the 145- MHz radio (when it transmits) may cause interferences
for 430- MHz radio.
Schematic of a simple Low Pass Filter for
145- MHz Band is shown in Figure 1. The
filter made on a piece of two sided PCB. Capacitors of the filter
are created on the board by the foil. Figure
2 shows design of the filter. Figure 3 shows view of the
filter. Figure 4 shows
layout of the capacitors.
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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.
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