Hi Hugh, two possible methods, one, put the power through the meter into a
dummy lead, and measure the voltage generated across the load with a scope
(easiest) or using an RF diode probe (but there is another calibration
problem there). (Remember peak-to-peak voltage is 2.8 * rms )
Meters of this type are probably only accurate to about 10% and that is
adequate for most amateur aerial work, as you are mainly looking for
changes....increases!!. Another way would be to put it in series with an RF
thermoammeter (if you are lucky enough to have one) The bandwidth of the
meter will depend on the ferrite used, and the number of turns.

Cheers de Alan G3NYK
-----Original Message-----
From: g6tmk <[email protected]>
To: [email protected] <[email protected]>
Date: 15 November 2002 10:45
Subject: LF: Calibrating LF Current Meters

Hi All,
I built the little antenna current meter shown in the LF Experimenters
Handbook last night (Page 81).
And it works. I measured the current from my HF rig into a dummy load at
1.8MHz, and it gave sensible results ...
But how can I calibrate it - how do I know that an indicated Amp really is
an Amp.
My DVMs, being intended for mains current measurement, don't have the
frequency response.
How have other people done it ?  Any ideas ?
73
Hugh M0WYE