Return-Path: Received: from mtain-mc07.r1000.mx.aol.com (mtain-mc07.r1000.mx.aol.com [172.29.96.79]) by air-di03.mail.aol.com (v127_r1.1) with ESMTP id MAILINDI033-eac04b9babb220e; Sat, 13 Mar 2010 10:13:54 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mc07.r1000.mx.aol.com (Internet Inbound) with ESMTP id 01DC1380000B3; Sat, 13 Mar 2010 10:13:47 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NqT0P-0004NN-Ic for rs_out_1@blacksheep.org; Sat, 13 Mar 2010 15:11:57 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NqT0P-0004NE-2l for rsgb_lf_group@blacksheep.org; Sat, 13 Mar 2010 15:11:57 +0000 Received: from mail-bw0-f215.google.com ([209.85.218.215]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NqT0M-0002Uh-Vj for rsgb_lf_group@blacksheep.org; Sat, 13 Mar 2010 15:11:57 +0000 Received: by bwz7 with SMTP id 7so1858427bwz.4 for ; Sat, 13 Mar 2010 07:11:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=ZBadhPP07kZX5IW8NmbGmY3aEOr5HdyMAnL0wybHGXg=; b=MmjF31FvE2BZvOlR2SFM34PZkFJOp9XRwvVFY/DXY4V71GgohNMSsBrFePXQLdEga6 o/hYs4j1rgZHZDu0GC2HOKbgJat9TUlNQ1tqldV4uXONF7C85Zyz4swC/UDf1qvAVCVT Ior3vwj3c0A4jhvzXkoaXNtUOEsFdtjgKCqyY= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=N95+Ov33dFqkKEfsTuGY6AIVgxjhCsNE9W5dMT75GQlr3xjQqloTtToW3UKgnujl51 h5Z8kYV+guETu9TvGVaQD3Cp+Bjq6h2SjgkYOmfoImY47XHQAZ7aJ6yYbFGI6kBasxQw Mot5MZx5D5zc+kscb/zB0yk5+EdQlu2OrxlqA= MIME-Version: 1.0 Received: by 10.204.33.135 with SMTP id h7mr792828bkd.186.1268493107491; Sat, 13 Mar 2010 07:11:47 -0800 (PST) In-Reply-To: <788098.62465.qm@web28103.mail.ukl.yahoo.com> References: <788098.62465.qm@web28103.mail.ukl.yahoo.com> Date: Sat, 13 Mar 2010 15:11:47 +0000 Message-ID: <9afca2641003130711k54c46755lf540477d2520a049@mail.gmail.com> From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.1 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,HTML_TAG_EXIST_TBODY=0.126 Subject: Re: LF: Re: Induction DX? Content-Type: multipart/alternative; boundary=00032555642e1274f90481b011f4 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30,HTML_MESSAGE, HTML_TAG_EXISTS_TBODY autolearn=no version=2.63 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-aol-global-disposition: G X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d305.2 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d604f4b9babab6d8c X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --00032555642e1274f90481b011f4 Content-Type: text/plain; charset=ISO-8859-1 Agreed, an interesting site with useful audio clips. What power and loop size did you use in your 0.5-1kms range induction comms tests Peter? 73s Roger G3XBM On 13 March 2010 12:01, M0FMT wrote: > Hi Jacek and group > > That is a very good site and the sound clips help identify stations like > the Alpha nav aids. > That is a really dedicated guy, I liked the auto signals I never thought > they would radiate so well. I have had a similar experience to his with very > low power at a range of about 1/2 to 1 km range at 7.8kc/s but at 1.8kc/s it > shows there is promise on these VLF frequences. > > Thanks for the URL Jacek. That site should be an inspiration to all of us > experimental ops! > > 73 es GL petefmt > > --- On *Sat, 13/3/10, Jacek Lipkowski * wrote: > > > From: Jacek Lipkowski > Subject: Re: LF: Re: Induction DX? > > To: rsgb_lf_group@blacksheep.org > Date: Saturday, 13 March, 2010, 9:14 > > > On Thu, 11 Mar 2010, James Moritz wrote: > > > It is interesting to try to work out what might be possible by > induction... > [...] > > have a look at > http://www.home.pon.net/785/equipment/transmitting/VLF_transmit_2.htm > > this experiment used two triangular loops of 15m high and 90m circumfrence > in a natural area (without conductors etc). > > the author was able to copy a 0.5W cw signal at the distance of 3.3km! > > this is much more, than what is expected from free-space calculations > mentioned in this thread. this is probably the effect of the ground > (currents induced in the ground excite some much bigger ground loops that > make up a "secondary" antenna of bigger size). > > another explamantion would be that the field induced at the transmitter > site got into the 2m receiver that the author was using, but i hope that is > not the case :) > > VY 73 > > Jacek / SQ5BPF > > > > -- http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/G3XBM G3XBM GQRP 1678 ISWL G11088 --00032555642e1274f90481b011f4 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Agreed, an interesting site with useful audio clips.

What power and= loop size did you use in your 0.5-1kms range induction comms tests Peter?=

73s
Roger G3XBM

On 13 March= 2010 12:01, M0FMT <m0fmt@yahoo.co.uk> wrote:
Hi Jacek and group
=A0
That is a very good site and the sound clips help identify stations= like the Alpha nav aids.
That is a really dedicated guy, I liked the auto signals I never thou= ght they would radiate so well. I have had a similar experience to his=A0w= ith very low power=A0at a range of about 1/2 to 1 km range at 7.8kc/s but= at 1.8kc/s it shows there is promise on these VLF frequences.
=A0
Thanks for the URL Jacek. That site should be an inspiration to all= of us experimental ops!

73 es GL petefmt

--- On Sat, 13/3/10, Jacek Lipkowski= <sq5bpf@l= ipkowski.org> wrote:

From: Jacek Lipkowski <sq5bpf@lipkowski.org>
Su= bject: Re: LF: Re: Induction DX?

To: = rsgb_lf_group@blacksheep.org
Date: Saturday, 13 March, 2010,= 9:14


On Thu, 11 Mar 2010, James Moritz wrote:

> It is interestin= g to try to work out what might be possible by induction...
[...]
have a look at http://www.home.pon.net/785/equ= ipment/transmitting/VLF_transmit_2.htm

this experiment used two triangular loops of 15m high and 90m circumfr= ence in a natural area (without conductors etc).

the author was abl= e to copy a 0.5W cw signal at the distance of 3.3km!

this is much= more, than what is expected from free-space calculations mentioned in thi= s thread. this is probably the effect of the ground (currents induced in= the ground excite some much bigger ground loops that make up a "seco= ndary" antenna of bigger size).

another explamantion would be that the field induced at the transmitte= r site got into the 2m receiver that the author was using, but i hope that is not the case :)

VY 73

Jacek / SQ5BPF






--

http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/G3XBM
G3XBM =A0 =A0GQRP 1678 =A0 =A0 =A0ISWL G11088
--00032555642e1274f90481b011f4--