[Lowfer] Measuring TX loop current

[we0h at yahoo.com]

Build one of those toroid current probes. 200 turns? Or something like that. John Andrew's has a description on his website I believe.
Mike
WE0H/8
------Original Message------
From: Bill Ashlock
Sender: lowfer-bounces at mailman.qth.net
To: lowfer at mailman.qth.net
ReplyTo: Discussion of the Lowfer \(US, European, &UK\) and MedFer bands
Subject: [Lowfer] Measuring TX loop current
Sent: Sep 21, 2009 7:24 PM


Rick,

 

The following two lines were copied from Lyles clamp-on current probe article: "An ideal ammeter should introduce zero impedance into the circuit it is measuring. This sensor adds a series impedance of less than half an ohm to the circuit under test at 200 kHz". Lyle's probe was designed to be used for measuring vertical antennas where typically half an ohm of series impedance is normally insignificant. Since your loop has an Rac of approx 1 ohm this probe, with the number of turns and resistive load given, would read the loop current approx 30% low. If you would like I can come up with a better choice for these values when measuring your loop.

 

Bill
 
 		 	   		  
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