Don wrote:
>There is no such thing a an "rf power" meter, at least when we are >talking about an instrument that most amateurs could afford. The so->called "wattmeters" are really rf voltmeters calibrated to the read the >level of power delivered when the measured voltage is imposed across a >known resistance. Most rf wattmeters are calibrated to work into a 50 or >72-ohm load. At any other load impedance, the reading is erroneous. While a true wattmeter is an absorption type of instrument, the wattmeters like the Bird and many other thru line meters measure voltage and current to determine power on the line. They will accurately measure at impedances other than 50 ohms too. You just subtract the amount of reflected power indicated from the forward power indicated for true forward power. It also doesn't matter if the load is reactive either as these type wattmeters will read true within their capability. 73 Gary K4FMX ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
