> Adding a bunch to the confusion :
> Why antenna or baloon constructors say ;
> Max power ( as an example )
> ssb/1500 w
> cw/750 w
> rtty/500 w
>
[Steve Katz] Well, I don't know about Belgium, but here in the
States, we rate baloons in pounds per square inch, or cubic feet, or
something like that. I never saw one rated in Watts! <hi hi>
Seriously, this is based on heating effect only. If the limiting
factor in a component is voltage breakdown, then "mode" would have nothing
to do with it. But if it's heating, then obviously, RTTY, with 100% duty
cycle, will create more heat in any dissipative component than CW, with ~50%
duty cycle, or SSB, with even lower duty cycle than that. Heating is
usually from IR loss in materials. If the component were lossless, it would
have an unlimited power rating...
-WB2WIK/6
> Just rember something ( 1950 ) like first derivation and the second
> derivation of a sine........
> Why two-tone is used when measuring .....?
>
> Jos on4kj
>
> ----- Original Message -----
> From: "Bill Fuqua" <wlfuqu00@uky.edu>
> To: <amps@contesting.com>
> Sent: Thursday, November 07, 2002 8:41 PM
> Subject: [Amps] RMS-PEP & 2x8877
>
>
> > When this came back the columns were messed up. I hope this is better.
> >
> > OK enough...
> > RMS has one meaning, definition or procedure if you want to call it
> that.
> > R take square root
> > of
> > M the average (mean)
> > of
> > S the square of a number of data points
> > It may look complicated as an equation or an integral expression
> (calculus)
> > but it is SIMPLE!!!!
> > For example...
> >
> > Take one cycle of a 1 volt peak sine wave and divide into at least 8
> > equally spaced points starting at zero degrees.
> > Calculate instantaneous voltage, voltage squared and power into 50 ohms
> > load at each point.
> > Do not use 360 degrees because it is the same point as 0 degrees. You
> may
> > do this for any number
> > of full cycles and you may want to do this on a spread sheet for each
> > degree (ie 360 points) or what ever.
> > Phase Voltage Voltage Squared Power into 50
> ohms
> > Degrees
> Watts
> > 0 0 0
> > 0
> > 45 .7071 .5
> > .01
> > 90 1 1
> > .02
> > 135 .7071 .5
> > .01
> > 180 0 0
> > 0
> > 225 -.7071 .5
> > .01
> > 270 -1 1
> > .02
> > 335 -.7071
> > . 5 .01
> > totals 0 4
> > .08
> >
> > average of
> > totals 0 .5 .01
> >
> > Square Root of average of
> > the voltage squared .7071
> >
> > The RMS value of the signal is .7071 times the peak (1 Volt)= .7071
> volts
> > GEE look at above bold and underlined.
> > What is the power of this signal into a 50 ohm load?
> > .7071 volts squared divided by 50 ohms= .01 watts Look again above at
> the
> > average power bold.
> > It is all very consistent with calculations using RMS voltage or Current
> > and resistance and power.
> > Now what happens when we take RMS of the Power??
> >
> > Phase Voltage Voltage Squared Power into 50
> > ohms Power Squared
> > Watts
> > 0 0 0
> 0
> > 0
> > 45 .7071 .5 .01
> > .0001
> > 90 1 1
> .02
> > .0004
> > 135 .7071 .5 .01
> > .0001
> > 180 0 0
> 0
> > 0
> > 225 -.7071 .5 .01
> > .0001
> > 270 -1 1
> .02
> > .0004
> > 335 -.7071 .5 .01
> > .0001
> > totals 0 4
> .08
> > .001
> >
> > average of
> > totals 0 .5
> .01
> > .00015
> >
> > Square Root
> > of
> > average 0 .7071
> > 0.01225 RMS power
> ?????
> > OK above is your RMS power for what ever good it is....
> > And it does not relate to any of the other numbers you may use such as
> > voltage, current. resistance or power. But does give you 22.5% bigger
> > number in this example.
> > 73
> > Bill wa4lav
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
> >
>
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
|