[Elecraft] Vrms measurements with oscilloscope

[Don Brown]

Hi

What is really needed is a troubleshooting guide with waveshape and amplitude pictures of the readings taken with a scope or at least peak to peak readings at the same test points used for the RF probe. A scope inherently measures peak to peak or ground to peak (which is just another form of peak to peak). Trying to get meaningful readings to correlate with a RF probe is not going to work very well unless the waveshape is a pure sine wave.

Your Fluke will measure true RMS but not at RF frequencies. Most DVMs only have a bandwidth of 10-20 KHz on AC.


Don Brown
KD5NDB
   
  ----- Original Message ----- 
  From: Jean-François Ménard<mailto:k2 at cima.ca> 
  To: 'Mailingliste Elecraft'<mailto:elecraft at mailman.qth.net> 
  Sent: Wednesday, June 23, 2004 7:47 AM
  Subject: RE : [Elecraft] Vrms measurements with oscilloscope


  I have the same concern about these mesurements. I bought a Fluke 123
  yesterday that read true rms values.

  I cannot get the range of value like in the manual... If someone could
  provide us some readouts using the standard RF in the kit and also for the
  same place, the readouts in Vrms with a scope would be really appreciated.


  -----Message d'origine-----
  De : elecraft-bounces at mailman.qth.net<mailto:elecraft-bounces at mailman.qth.net>
  [mailto:elecraft-bounces at mailman.qth.net] De la part de GS
  Envoyé : 23 juin 2004 08:31
  À : Mailingliste Elecraft
  Objet : [Elecraft] Vrms measurements with oscilloscope


  Hi,

  if I signal trace with my oscilloscope and want to
  know the Vrms values at certain points in my K2...

  ... is ist correct to measure the amplitude (not peak
  to peak) of the signal and then divide by the square
  root of 2?

  Will I get values I can check against the given Vrms
  values in the manual?

  Thanks

  Gerhard







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