>
>>In tuning high power amps, a CW signal will drive the watt meter to a
>>given level while reading the PO on the average watts scale of the meter
>>(Autek WM-1).
>
>Peak and average power for a CW signal is identical.
>
? ... only if the anode-supply is regulated. For a garden-variety
amplfier with an unregulated anode-supply, an oscilloscope indicates more
RF peak volts at the beginning of a dash than it does at the end. On my
SB-220, the difference is more than 5%, and so is the HV sag.
>>Then switch the watt meter to "peak", and modulating with a SSB note,
>>the peak level is not much higher. The amp has 3, 3CX800A's, and should
>>carry max PO. Is it?
>>
>
>A lot depends here. First of all how good is your peak reading meter?
>How fast is it? SSB voice peaks are pretty short. My Daiwa has a peak
>hold function and using that, my peak power is the same as on CW. Also,
>how strong are you modulating? Is your mic gain set correctly?
>
>>Also, I have noticed some watt meters advertising TRUE peak power
>>readings, like the new Amertron AWM-30. Is there a difference between
>>peak power and True peak power?
>
>Sounds like MFJ-style advertising.
? amen, Jon. .
>
>> Am I reading the real SSB power, and is
>>there a needle delay on the upswing of the plate meter and the peak
>>power meters?
>
>Sure there's a needle delay. That's why you really can't see peak power
>on a normal meter. The movement is too slow to catch the peak. I think
>a peak meter will typically have some sort of detector and dampening
>circuit in it that will allow detection of the peak and will remember it
>after the peak is passed.
>
>Bottom line is if you are modulating correctly, your SSB peak and CW peak
>powers should be the same.
? true enough, Jon.
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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