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Message-ID: <788098.62465.qm@web28103.mail.ukl.yahoo.com>
Date: Sat, 13 Mar 2010 04:01:16 -0800 (PST)
From: M0FMT <m0fmt@yahoo.co.uk>
To: rsgb_lf_group@blacksheep.org
In-Reply-To: <Pine.LNX.4.64.1003130958310.19701@paranoid.lipkowski.org>
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Subject: Re: LF: Re: Induction DX?
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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 thought=
 they would radiate so well. I have had a similar experience to his=A0with=
 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@lipkowski.org> wrote:


From: Jacek Lipkowski <sq5bpf@lipkowski.org>
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_tran=
smit_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 ment=
ioned 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 si=
te got into the 2m receiver that the author was using, but i hope that is=
 not the case :)

VY 73

Jacek / SQ5BPF





     =20

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<table cellspacing=3D"0" cellpadding=3D"0" border=3D"0" ><tr><td valign=3D=
"top" style=3D"font: inherit;"><DIV>Hi Jacek and group</DIV>
<DIV>&nbsp;</DIV>
<DIV>That is a very good site and the sound clips help identify stations=
 like the Alpha nav aids.</DIV>
<DIV>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&nbs=
p;with very low power&nbsp;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.</DIV>
<DIV>&nbsp;</DIV>
<DIV>Thanks for the URL Jacek. That site should be an inspiration to all=
 of us experimental ops!</DIV>
<DIV><BR>73 es GL petefmt<BR><BR>--- On <B>Sat, 13/3/10, Jacek Lipkowski=
 <I>&lt;sq5bpf@lipkowski.org&gt;</I></B> wrote:<BR></DIV>
<BLOCKQUOTE style=3D"BORDER-LEFT: rgb(16,16,255) 2px solid; PADDING-LEFT:=
 5px; MARGIN-LEFT: 5px"><BR>From: Jacek Lipkowski &lt;sq5bpf@lipkowski.org=
&gt;<BR>Subject: Re: LF: Re: Induction DX?<BR>To: rsgb_lf_group@blacksheep=
.org<BR>Date: Saturday, 13 March, 2010, 9:14<BR><BR>
<DIV class=3DplainMail>On Thu, 11 Mar 2010, James Moritz wrote:<BR><BR>&gt=
; It is interesting to try to work out what might be possible by induction=
...<BR>[...]<BR><BR>have a look at <A href=3D"http://www.home.pon.net/785/=
equipment/transmitting/VLF_transmit_2.htm" target=3D_blank>http://www.home=
.pon.net/785/equipment/transmitting/VLF_transmit_2.htm</A><BR><BR>this exp=
eriment used two triangular loops of 15m high and 90m circumfrence in a na=
tural area (without conductors etc).<BR><BR>the author was able to copy a=
 0.5W cw signal at the distance of 3.3km!<BR><BR>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).<BR><BR>another explamantion would be that the field indu=
ced at the transmitter site got into the 2m receiver that the author was=
 using, but i hope
 that is not the case :)<BR><BR>VY 73<BR><BR>Jacek / SQ5BPF<BR><BR><BR></D=
IV></BLOCKQUOTE></td></tr></table><br>



     =20

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