I missed this question on the first pass. When the amplifier is tuned for
maximum power out, the Q has virtually nothing to do with peak tank circuit
voltages. It has everything to do with circulating currents and that will
increase losses if the Q is too high.
Peak voltages are related to the power generated and plate load impedance.
RMS voltage = square root of power times impedance when the tank is loaded
and resonant. Peak voltage is 1.414 times rms voltage.
73,
Gerald K5GW
In a message dated 1/29/2011 7:36:18 A.M. Central Standard Time,
ka4inm@tampabay.rr.com writes:
Hi Steve Cook:
> The question I watching for an answer to was:
> I the Q changes (because the tank L is set to a non optimal inductance
> value) what happens to the voltages across the plate tune and antenna
> loading capacitors.
> The original question, as I read it, did not address open antenna
> connections or the like.
> So for me, if I want to operate on 10MHz with my Kenwood TL-922 amp
> which does not have a setting for 10MHz -- do I need to operate at
> reduced voltage to keep the tank voltages from soaring?
> Did I get the question wrong?
> I still don't know what the answer is.
> What happens to the tank voltages when the Q goes up or down due to the
> setting of the tank inductance???
A well asked question. I didn't recall the original question.
First we are allowed only 200 Watts, so 3dB over a 100 Watt transceiver
will not be noticeable. If
the "tank" is not resonant the efficiency will be extremely low, if the
transformer ratio is
incorrect (the two capacitors form a auto-transformer) because of the
incorrect inductance the
loading will be too high or too low, depending. The "plate tune"
capacitor can easily arc at the
capacitor, it is unlikely that the "loading capacitor" would arc as the
load will remain across it.
BTW: Wikipedia says "CW only" and the ARRL says "RTTY and data" ??? and
it is only good for
contacts within USA, so I see no use for using it without some special
interest.
--
Ron KA4INM - If you have any criticism for me constructive or otherwise
keep it to yourself, at my age I just don't care anymore.
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