From: Rik Strobbe <[email protected]>
Subject: LF: RE: VLF - vertical probe measurements
To: "[email protected]" <[email protected]>
Date: Friday, 15 April, 2011, 14:11

Hello Chris,

 

maybe a stupid question (wouldn't be my first one): how do you alter the PA current ?

If you change the PA current by changing the PA voltage then the output power will change more or less with the square of tht PA current (P = UxI and you change both U and I), what would result in a linear behaviour between PA current and probe voltage.

 

73, Rik  ON7YD - OR7T

 

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Van: [email protected] [[email protected]] namens Chris Osborn [[email protected]]
Verzonden: vrijdag 15 april 2011 14:40
Aan: LF Group
Onderwerp: LF: VLF - vertical probe measurements

LF,   Acting on advice I have installed a whip aerial (probe) on top of a mast at the boundary of my property. This is in order to monitor my VLF transmissions and to provide a reference level for any system improvements.   I noticed that the probe's pick-up voltage is directly proportional to my PA's supply current. Assuming that the PA efficiency doesn't change drastically with current then would I be correct in assuming that the probe's voltage is directly proportional to the radiated power?   I was expecting a square law relationship . .   73 Chris G3XIZ