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![]() Antonio Vernucci wrote: Because active SWR meters do not usually suffer from this effect, they can normally be left in without causing such problems Can anyone clearly explain what is an "active" SWR meter? I would presume that the line is decopled from the diode by means of an amplifier. Is that what they mean? 73 Tony I0JX In this neck of the woods "active" usually means the meter has peak reading circuitry that requires power to operate. In general, as far as ordinary peak reading meters, this is the most accurate type as far as trying to read voice peaks. The better ones use fast acting LED's as the meter. A "passive" meter is one that uses capacitors to give the meter a "hang time" to sort of read peaks. But it's not as accurate, and almost always reads low. "20-25% worth" for the average meter. The cross needle meter in my MFJ-989C is an example of a passive meter circuit. I call it "psuedo peak reading". :/ I also built a passive circuit into my old green cube heathkit meter. It has a switch on the back to switch the caps in or out. Naturally, the passive meters require no power to operate. MK |
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