Return-Path: Received: (qmail 28263 invoked from network); 21 Nov 2001 14:40:44 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 21 Nov 2001 14:40:44 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 11236 invoked from network); 21 Nov 2001 14:40:50 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 21 Nov 2001 14:40:50 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 166YRQ-0001sC-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 21 Nov 2001 14:33:32 +0000 Received: from imo-r04.mx.aol.com ([152.163.225.100]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 166YRP-0001s7-00 for rsgb_lf_group@blacksheep.org; Wed, 21 Nov 2001 14:33:31 +0000 Received: from G0MRF@aol.com by imo-r04.mx.aol.com (mail_out_v31_r1.9.) id l.12d.7e7fade (25711) for ; Wed, 21 Nov 2001 09:32:43 -0500 (EST) From: G0MRF@aol.com Message-ID: <12d.7e7fade.292d150b@aol.com> Date: Wed, 21 Nov 2001 09:32:43 EST Subject: Re: LF: Measuring Q To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 X-Mailer: AOL 6.0 for Windows UK sub 10505 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Content-transfer-encoding: 8bit In a message dated 11/21/01 8:35:15 AM GMT Standard Time, g3ldo@ukonline.co.uk writes:


I connected the coil under test with a parallel air-spaced capacitor to the
signal generator via a variable capacitor. I coupled the coil to the level
meter with with just a clip on the insulation of the coil. I reduced the
coupling to the signal generator with the variable capacitor to minimum
while maintaining a good signal on the level meter.


Hello Peter.

I tried something similar about a year ago and found that any direct connection to the coil under test affected the results. Seems from your description you have some connections which may be influencing the results.

As a start I would suggest you try link coupling the signal in from the generator.

The 'sample' output is the other problem.
My solution was to use a capacitive divider......An airspaced variable in series with a large mica capacitor. The junction has a low impedance. Even so I used a 1M resistor then coupled that to a high Z oscilloscope.  The results were OK to a Q of 350 but after that it became unreliable.

Let us know if you resolve the problems.

GL es 73

David  G0MRF