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## Re: [TenTec] Voltages on 50 ohm Dummy Load

 To: Discussion of Ten-Tec Equipment Re: [TenTec] Voltages on 50 ohm Dummy Load Robert & Linda McGraw K4TAX Discussion of Ten-Tec Equipment Thu, 09 Jun 2005 21:55:58 -0500
 ```I'm really surprised at all the folks that missed the entire point. Look at the numbers again that I stated relating to 50 ohms: 70.710 volts x 1.414 amps = ~100 watts and 273.861 volts x 5.477 amps = ~1500 watts I said the measurement technique was to use the scope to measure peak to peak voltage. Reason being, most folks do not have RF volt meters and the HB probes using various diodes are as unreliable as they come without proper calibration techniques. Thus the scope is the easiest way and most accurate to make measurements in the HF spectrum. Yes the scope does present P - P values but I have to ask, do most folks know how to convert P - P values to RMS and do they know what the scope measures in terms of voltage units? Also I'd expect that few have accurate RF amp meters available to them. 73 Bob, K4TAX ----- Original Message ----- From: "Ken Brown" To: "Discussion of Ten-Tec Equipment" Sent: Thursday, June 09, 2005 7:49 PM Subject: Re: [TenTec] Voltages on 50 ohm Dummy Load > >>I measure the peak to peak value using my scope. Then power equals E >>squared divided by R. This is good enough for "government work". >> >> > This is wrong! Using peak voltage instead of RMS voltage of the peaks > will result in a power miscalculation by a factor of two. Using Peak to > Peak voltage instead of RMS voltage of the peaks would result in a > miscalculation by a factor of 8! > > Peak voltage is 1.414 X RMS. Peak to peak voltage is 2 X Peak or 2 X > 1.414 X RMS. When you square this in the power equation your > miscalculated power would be 8 X the actual power. > > DE N6KB > > > _______________________________________________ > TenTec mailing list > TenTec@contesting.com > http://lists.contesting.com/mailman/listinfo/tentec > _______________________________________________ TenTec mailing list TenTec@contesting.com http://lists.contesting.com/mailman/listinfo/tentec ```
 Current Thread [TenTec] Voltages on 50 ohm Dummy Load, Williams, Barry Re: [TenTec] Voltages on 50 ohm Dummy Load, Geoffrey S. Mendelson Re: [TenTec] Voltages on 50 ohm Dummy Load, Martin, AA6E Re: [TenTec] Voltages on 50 ohm Dummy Load, Martin, AA6E Re: [TenTec] Voltages on 50 ohm Dummy Load, Robert & Linda McGraw K4TAX Re: [TenTec] Voltages on 50 ohm Dummy Load, Martin, AA6E Re: [TenTec] Voltages on 50 ohm Dummy Load, Duane - N9DG Re: [TenTec] Voltages on 50 ohm Dummy Load, Ken Brown Re: [TenTec] Voltages on 50 ohm Dummy Load, Robert & Linda McGraw K4TAX <= Re: [TenTec] Voltages on 50 ohm Dummy Load, Ken Brown