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Date: Wed, 15 Dec 2010 22:45:13 +0000
Message-ID: <AANLkTimJ8m2uX_EKkMrUL1_0=T63ujXaZ_7oLXfFmDR4@mail.gmail.com>
From: Roger Lapthorn <rogerlapthorn@gmail.com>
To: rsgb_lf_group@blacksheep.org
DomainKey-Status: good (testing) 
Subject: Re: LF: Re: G3XBM - very long carrier VLF transmission test Dec 15th
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Dear Jim (and others),

Very many thanks for trying to detect my Dreamer's Band signal today. I was
aware of 3 stations definitely looking within 70km of my QTH and, not
surprisingly, not one was successful. I was hoping that a couple of stations
in the 10-20km range might have been looking and possibly might have had
marginal copy. As it was, only more distant stations were, to my knowledge,
looking. It is still possible some further reports will be received. If
anyone is interested I have a record of my transmission sequence/times
between 0900 and 2200z. The transmitter has now been turned off.

I am most interested in the ERP calculation suggested by Marcus and will
attempt to calculate the ERP for my present VLF system in the next few days.
I suspect it will be <<1uW. With this data I expect someone here will be
able to hazard a guess at what my far-field (radiated) range might
theoretically be, although I suspect "not very far" field at all :-)

My next test (probably after Christmas and in better weather) will be some
8.76kHz transmissions using the elevated (in the air) loop rather than the
earth electrodes to compare range. I would also like to do some more
"forensics" to try to better understand just how my signals are getting out
across the fens as well as they do locally and of course to find the
absolute limit of range with earth mode conduction or whatever mode it is.

Thanks again - even negative results are results.

73s
Roger G3XBM


On 15 December 2010 22:10, James Moritz <james.moritz@btopenworld.com>wrote:

> Dear Roger, LF Group,
>
> I left the VLF RX set up on your stated frequency today, but no signals
> have been detected so far. There was a rather curious spectrogram trace
> close to your stated frequency - see attachment - but I assume this is local
> QRM, since it repeats every 31Hz or so over the nearby frequency range, and
> I have seen similar things here before a number of times.
>
> Cheers, Jim Moritz
> 73 de M0BMU




-- 
g3xbm-qrp.blogspot.com/
www.g3xbm.co.uk
www.youtube.com/user/g3xbm
<http://vlf_grabber>G3XBM   GQRP 1678    ISWL G11088

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Dear Jim (and others),<br><br>Very many thanks for trying to detect my Dre=
amer&#39;s Band signal today. I was aware of 3 stations definitely looking=
 within 70km of my QTH and, not surprisingly, not one was successful. I wa=
s hoping that a couple of stations in the 10-20km range might have been lo=
oking and possibly might have had marginal copy. As it was, only more dist=
ant stations were, to my knowledge, looking. It is still possible some fur=
ther reports will be received. If anyone is interested I have a record of=
 my transmission sequence/times between 0900 and 2200z. The transmitter ha=
s now been turned off.<br>
<br>I am most interested in the ERP calculation suggested by Marcus and wi=
ll attempt to calculate the ERP for my present VLF system in the next few=
 days. I suspect it will be &lt;&lt;1uW. With this data I expect someone=
 here will be able to hazard a guess at what my far-field (radiated) range=
 might theoretically be, although I suspect &quot;not very far&quot; field=
 at all :-)<br>
<br>My next test (probably after Christmas and in better weather) will be=
 some 8.76kHz transmissions using the elevated (in the air) loop rather th=
an the earth electrodes to compare range. I would also like to do some mor=
e &quot;forensics&quot; to try to better understand just how my signals ar=
e getting out across the fens as well as they do locally and of course to=
 find the absolute limit of range with earth mode conduction or whatever=
 mode it is.<br>
<br>Thanks again - even negative results are results.<br><br>73s<br>Roger=
 G3XBM<br><br><br><div class=3D"gmail_quote">On 15 December 2010 22:10, Ja=
mes Moritz <span dir=3D"ltr">&lt;<a href=3D"mailto:james.moritz@btopenworl=
d.com">james.moritz@btopenworld.com</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin: 0pt 0pt 0pt 0.8ex; bord=
er-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Dear Roger, LF=
 Group,<br>
<br>
I left the VLF RX set up on your stated frequency today, but no signals ha=
ve been detected so far. There was a rather curious spectrogram trace clos=
e to your stated frequency - see attachment - but I assume this is local=
 QRM, since it repeats every 31Hz or so over the nearby frequency range,=
 and I have seen similar things here before a number of times.<br>

<br>
Cheers, Jim Moritz<br>
73 de M0BMU </blockquote></div><br><br clear=3D"all"><br>-- <br><a href=3D=
"http://g3xbm-qrp.blogspot.com/" target=3D"_blank">g3xbm-qrp.blogspot.com/=
</a><br><a href=3D"http://www.g3xbm.co.uk" target=3D"_blank">www.g3xbm.co.=
uk</a><br>
<a href=3D"http://www.youtube.com/user/g3xbm" target=3D"_blank">www.youtub=
e.com/user/g3xbm</a><br><a href=3D"http://vlf_grabber" target=3D"_blank"><=
/a>G3XBM=A0=A0 GQRP 1678=A0=A0=A0 ISWL G11088<br>

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