In a message dated 1/10/05 9:12:45 PM, [EMAIL PROTECTED] writes:
> Kinda Sorta. Depends on the quality of the transmitter. If he > reduces the carrier output power of the Ranger, then the audio > output power will rise, because there won't be as much final > current flowing through the secondary of the modulation > transformer. Depending on the impedance match of the final to > the modulator through the mod transformer, determins how much > more audio will be gained (or lost) when power is reduced from > the exciter. > Hmmm.. Goes without saying that however the carrier level was reduced the audio level should be concomitantly lowered to prevent over modulation. Easy to do, just reduce the mic gain control. > That, and the natural asymetricalness of the > operators voice. Lowering the output power, more audio, a 3:1 SR > (Symmetry Ratio), the 25w of carrier could contain as much as > 200w PEP. In order for the linear to 'cleanly' reproduce the > audio, it's going to need more than what the plates of a pair of > 3-500Z's can deliver (*note: I said "Cleanly") > > Two hundred watts PEP on a 25 watt carrier comes out to 400% modulation. Would take some extreme speech processing to achieve this in the positive direction while limiting modulation to 100% negative at the same time. Far beyond the asymmetry of "normal" human speech. So, a pair of 3-500Zs running GG and giving, say, 10db gain, with 35 watts of drive would give 350 watts of carrier out and modulating at 100% with a reasonably asymmetric audio signal would give 1400 W. PEP. I have been using a 3-1000Z linear in this way for years with excellent results. Speaking of the human voice, there undoubtedly exist some levels of asymmetry depending on the speaker. I suspect, however that much of the asymmetry observed and reported is actually the product of nonlinearities in speech amplifier circuitry, particularly in the early, low-level stages. Dennis D. W7QHO Glendale, CA
