Envelope-to: dave@picks.force9.co.uk Delivery-date: Sat, 21 May 2005 01:51:51 +0100 Received: from ptb-spamcore02.plus.net ([192.168.71.3]) by pih-mxcore09.plus.net with esmtp (PlusNet MXCore v1.0) id 1DZIDX-0000Qs-6V for dave@picks.force9.co.uk; Sat, 21 May 2005 01:51:51 +0100 Received: from Debian-exim by ptb-spamcore02.plus.net with spam-scanned (Exim 4.50) id 1DZIDQ-0002ap-Ut for dave@picks.force9.co.uk; Sat, 21 May 2005 01:51:48 +0100 Received: from [192.168.67.4] (helo=ptb-mxcore04.plus.net) by ptb-spamcore02.plus.net with esmtp (Exim 4.50) id 1DZIDQ-0002ag-Ra for dave@picks.force9.co.uk; Sat, 21 May 2005 01:51:44 +0100 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore04.plus.net with esmtp (PlusNet MXCore v1.0) id 1DZIHs-0006qd-Tl for dave@picks.force9.co.uk; Sat, 21 May 2005 01:56:21 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1DZICe-0001pf-7R for rs_out_1@blacksheep.org; Sat, 21 May 2005 01:50:56 +0100 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1DZICd-0001pW-L2 for rsgb_lf_group@blacksheep.org; Sat, 21 May 2005 01:50:55 +0100 Received: from smtp-out1.hurontel.on.ca ([216.46.129.246]) by relay.thorcom.net with esmtp (Exim 4.43) id 1DZICb-0006pM-Tl for rsgb_lf_group@blacksheep.org; Sat, 21 May 2005 01:50:55 +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 j4L0fVMl022110 for ; Fri, 20 May 2005 20:41:31 -0400 Received: from server (dial139-ripley2.hurontel.on.ca [216.46.149.139]) by mail.hurontel.on.ca (8.12.10+Sun/8.12.10) with SMTP id j4L0lpai015333 for ; Fri, 20 May 2005 20:47:52 -0400 (EDT) Message-ID: <002f01c55d97$09df4840$8c802ed8@server> From: "J. B. Weazle McCreath" To: rsgb_lf_group@blacksheep.org References: <000c01c55a6e$8d82f740$37d0fc3e@l8p8y6> <000d01c55b45$acb45e60$ac068351@w4o8m9> Date: Sat, 21 May 2005 00:52:19 +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: 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 LF Group,

I've finally finished the construction of my LF loop and I appear to have a

problem with it regarding the connection to the receiver. The loop itself

is in the form of an octagon, with an overall diameter of 10.5 feet, and it

consists of 15 turns of number 12 THHN stranded wire. The spacing of

the turns is 0.25 inch and the tuning is done with a 3 gang, 400 pF. per

section, variable capacitor with all sections connected in parallel.

Checking with a weak signal source, the tuning range is roughly 100 to

300 kHz. This agrees with Reg's program for multi-turn loop antennas.

A portable radio covering the LF band really comes to life when I bring

it close to the loop, and by turning the loop in azimuth I can peak the

signals and/or null out noise. This would indicate that it is working as

I would expect.

The problem is with the pickup loop, which is of the classical shielded

construction as described in many antenna books. Mine is made from

RG-213 coax and it's positioned roughly six inches inside of the main

loop windings, but in the same plane. The station receiver, a TS-440S,

gets better reception of LF signals when it's connected to my 40 meter

delta loop than it does with the LF loop!! I know the feedline is OK, as

I've checked it with an MFJ-259 antenna bridge and a 50 ohm load at

the antenna end.

The one suspicion I do have is that the cable clamps I've used to hold

the pickup loop to the frame are made of metal and are shaped like a

capital letter P. I'm wondering if these look like shorted turns to the

pickup loop and are attenuating the signal? Before I get out my big

stepladder and replace them, I thought I'd ask the opinions of those

of you who have gone before me. Any/all suggestions are welcome.

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