-----Original Message-----
From: Richard <2@mail.vcnet.com>
To: Steve Thompson <g8gsq@qsl.net>; Amps <amps@contesting.com>
To: <amps@contesting.com>
Date: 26 March 2002 05:35
Subject: Re: [Amps] SB-220 WARC bands
>> >Good meters, like the Bird 43, have +-5% of full scale anywhere on
>> >the scale tolerance if they are within factory specs. Other meters
>> >are generally worse for tolerance. So a 2500w slug in a properly
>> >calibrated Bird 43 at 1000 watts true power could read between 875
>> >and 1175 watts. People often pretend Bird meters are 0%
>> >tolerance, but that is dreaming.
>>
>> ? Or wishful thinking. Furthermore, the accuracy of any RF wattmeter is
>> dependant on the measured resistance of the termination. If a wattmeter
>> is calibrated for 50? and the termination is 87?, the wattmeter will
>> provide a reading that has no basis in reality.
>If the feedline and meter have the same Zo and the sampling system has
>sufficient directivity, the meter will show the forward and reflected power
>accurately, even if the termination is not Zo. The difference between
>forward and reflected power is either heating the feeder or radiated.
>
? Steve -- Does it say this in the Bird® 43 manual ?
Sorry, but I've no idea.
Steve
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