>On Monday 25 March 2002 14:25, Richard wrote:
>> >> Power out on 12 and 17m is around 400W and 30m doesn't really work at
>> >> all. The reason for the low output, compared to all of you who
>> >> answered (most of you have over 1KW out), I don't know. Are the tubes
>> >> tired or do I have too little driving power. The IC-765 only delivers
>> >> 90-100W and that, I know, is not enough to drive 2x3-500Z to full
>> >> output. The output from the amp is anywhere from 600-900W depending on
>> >> band, 10-80M.
>> >
>> >The factory designed rating for the SB-220 is 1kW INPUT (~600w
>> >output) on CW and RTTY, and 2KW PEP on SSB (~1200 watts
>> >PEP out) on SSB.
>> >
>> >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 ?
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
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