Envelope-to: dave@picks.force9.co.uk Delivery-date: Sat, 21 May 2005 14:28:24 +0100 Received: from ptb-spamcore02.plus.net ([192.168.71.3]) by pih-mxcore06.plus.net with esmtp (PlusNet MXCore v1.0) id 1DZU1g-0005dw-T9 for dave@picks.force9.co.uk; Sat, 21 May 2005 14:28:24 +0100 Received: from Debian-exim by ptb-spamcore02.plus.net with spam-scanned (Exim 4.50) id 1DZU1g-0005Bg-74 for dave@picks.force9.co.uk; Sat, 21 May 2005 14:28:24 +0100 Received: from [192.168.101.77] (helo=pih-mxcore11.plus.net) by ptb-spamcore02.plus.net with esmtp (Exim 4.50) id 1DZU1g-0005Bd-3e for dave@picks.force9.co.uk; Sat, 21 May 2005 14:28:24 +0100 Received: from post.thorcom.com ([193.82.116.20]) by pih-mxcore11.plus.net with esmtp (PlusNet MXCore v1.0) id 1DZU1f-0007JV-Ps for dave@picks.force9.co.uk; Sat, 21 May 2005 14:28:23 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1DZU1I-0003hs-TH for rs_out_1@blacksheep.org; Sat, 21 May 2005 14:28:00 +0100 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1DZU1I-0003hj-ED for rsgb_lf_group@blacksheep.org; Sat, 21 May 2005 14:28:00 +0100 Received: from smtp-out1.hurontel.on.ca ([216.46.129.246]) by relay.thorcom.net with esmtp (Exim 4.43) id 1DZU1H-0001gE-PB for rsgb_lf_group@blacksheep.org; Sat, 21 May 2005 14:28:00 +0100 Received: from mail.hurontel.on.ca (mail.hurontel.on.ca [216.46.129.11]) by smtp-out1.hurontel.on.ca (8.13.1/8.13.1) with ESMTP id j4LDJePe020309 for ; Sat, 21 May 2005 09:19:40 -0400 Received: from server (dial-109.hurontel.on.ca [216.46.128.109]) by mail.hurontel.on.ca (8.12.10+Sun/8.12.10) with SMTP id j4LDQ0Gv015928 for ; Sat, 21 May 2005 09:26:03 -0400 (EDT) Message-ID: <005301c55e00$e36e6140$8c802ed8@server> From: "J. B. Weazle McCreath" To: rsgb_lf_group@blacksheep.org References: <000c01c55a6e$8d82f740$37d0fc3e@l8p8y6> <000d01c55b45$acb45e60$ac068351@w4o8m9> <002f01c55d97$09df4840$8c802ed8@server> <002101c55ddf$d9c78930$546ca450@preinstapdq0tf> Date: Sat, 21 May 2005 13:30:13 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2720.3000 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-SPF-Result: relay.thorcom.net: 216.46.129.246 is neither permitted nor denied by domain of hurontel.on.ca Subject: LF: Re: Re: Loop antenna problem Content-Type: text/html; charset=windows-1252 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Filtered: by PlusNet SpamCORE (v4.00s) Content-transfer-encoding: 8bit

Hello Niels, LF group,

Yes, it is a rather large loop! I have a few pix of it if anyone would like to

see how I've built it. Your guess of the inductance is close, I measured

it with my LCR-55 meter and it's 2150 uH. or about 2.1 mH. According

to Reg's loop program the self resonance is about 800 kHz. and the Q

is 383, but I've no way to verify the latter.

At this point I'm game to try any suggestions to see if I can improve on

the performance (or lack thereof at the moment) I think I'll try a simple

one turn unshielded pickup loop next, but I'll certainly keep your idea

of a capacitive divider in mind.

73, J.B. Weazle McCreath, VE3EAR - VE3WZL

Dr om!

Quite a big loop you have made there!

I would not recommend the use of a pickup loop at all. It is rather

difficult to predict the degree of coupling between the loop prober and

the pickup loop.

From your description I guess that your loop inductance is about 2 mH,

as for the Q of the loop I would say it lies between 20 and 50.

Why not try to scrap the heavy RG213 loop and instead use a

capacitive divider . If you try a capacitor of 10 to 22 nF in series

with your variable capacitor, you might have success.

As for the question of balancing etc. in order to avoid capacitive signal

pickup, I suggest you try to solve that problem with an isolating

transformer. But let that be a second exercise!

73

Niels/OZ8NJ+