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[195.171.43.25]) by mx.google.com with ESMTP id gf2si14068160wjb.49.2014.03.08.09.08.52 for ; Sat, 08 Mar 2014 09:08:53 -0800 (PST) Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25; Authentication-Results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1WMKFk-00053m-RN for rs_out_1@blacksheep.org; Sat, 08 Mar 2014 16:37:36 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1WMKFk-00053d-34 for rsgb_lf_group@blacksheep.org; Sat, 08 Mar 2014 16:37:36 +0000 Received: from blu0-omc1-s26.blu0.hotmail.com ([65.55.116.37]) by relay1.thorcom.net with esmtp (Exim 4.82) (envelope-from ) id 1WMKFh-0005pK-HK for rsgb_lf_group@blacksheep.org; Sat, 08 Mar 2014 16:37:34 +0000 Received: from BLU180-W8 ([65.55.116.7]) by blu0-omc1-s26.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Sat, 8 Mar 2014 08:37:32 -0800 X-TMN: [132ltAqWF4A0TW2N8czehN81EfqKz14D] X-Originating-Email: [rjraide@hotmail.com] Message-ID: From: Bob Raide To: "rsgb_lf_group@blacksheep.org" Date: Sat, 8 Mar 2014 11:37:31 -0500 Importance: Normal In-Reply-To: <531B1D0C.3070208@abelian.org> References: <2662DF5AA7FA416CBB09CDB90BBFF7B1@White> <016101cf39df$4f4c89a0$ede59ce0$@comcast.net>, <01dc01cf3a3f$86997bb0$93cc7310$@comcast.net>, <2FC5CAB271A6437CB35A5B100185CEDA@White> <025101cf3a52$e0925750$a1b705f0$@comcast.net> <7DB9DD5669FC4C648838510DCAC08AFB@White> <531A506E.9040103@abelian.org> <531A5C19.9060209@abelian.org> <02ba01cf3aa3$debaad50$9c3007f0$@comcast.net> <531AF126.2060600@abelian.org> <850A470A5B9F4483BED8B49D4791044A@White>,<531B1D0C.3070208@abelian.org> MIME-Version: 1.0 X-OriginalArrivalTime: 08 Mar 2014 16:37:32.0407 (UTC) FILETIME=[B406C870:01CF3AEC] X-Spam-Score: -0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Paul; Wonder what effects soil conductivity changes has on the propagation at these VLF freqs?? Temperature here this pasted week has been and averaged 4-8 F degrees. Yesterday and last night temp climbed to 40+F! It is a fact that the conductivity in this region changes drastically with temperature. Much higher with freezing temps. Usual conductivity of 3-4 at above freezing and upwards of 10-15 with cold temperatures-the colder the higher the conductivity-Bob [...] Content analysis details: (-0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [65.55.116.37 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (rjraide[at]hotmail.com) -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: 40cd937fc1c5e6338b07d288cd09d087 Content-Type: multipart/alternative; boundary="_8a365b8e-09d1-4360-8ae5-ec218de85aec_" Subject: RE: LF: Daytime 29.499 kHz X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.1 required=5.0 tests=FORGED_HOTMAIL_RCVD, HTML_MESSAGE,MAILTO_TO_SPAM_ADDR,TO_ADDRESS_EQ_REAL 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 --_8a365b8e-09d1-4360-8ae5-ec218de85aec_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Paul=3B Wonder what effects soil conductivity changes has on the propagation at the= se VLF freqs?? Temperature here this pasted week has been and averaged 4-= 8 F degrees. Yesterday and last night temp climbed to 40+F! It is a fact = that the conductivity in this region changes drastically with temperature. = Much higher with freezing temps. Usual conductivity of 3-4 at above freez= ing and upwards of 10-15 with cold temperatures-the colder the higher the c= onductivity-Bob =20 > Date: Sat=2C 8 Mar 2014 13:37:16 +0000 > From: vlf0403@abelian.org > To: rsgb_lf_group@blacksheep.org > Subject: Re: LF: Daytime 29.499 kHz >=20 > Here is the background noise diurnal for 2013 at 29.5kHz >=20 > http://abelian.org/vlf/tmp/29499_noise_2013.png >=20 > The noise is averaged over a 500Hz band and converted to units > of fT per root Hz. >=20 > The noise is before sferic blanking. Divide the noise > amplitude by 10 to estimate the noise after blanking. >=20 > Multiply the noise amplitude by the square root of your > bandwidth to obtain your RMS noise floor. Or instead=2C divide > the noise by the square root of your Fourier transform width > in seconds. >=20 > For example=2C from the plot the noise during the night in early > March is in the purple but on poor nights has a hint of red. > Lets say a bad night then is 15 fT/root(Hz). >=20 > After blanking that would be 1.5 fT=2C and in a 600 second Fourier > transform the floor would be 1.5/sqrt(600) =3D 0.06 fT in each > Fourier bin. >=20 > Compare that with the noise level between 19:00 and 21:00 in >=20 > http://abelian.org/vlf/tmp/29499_140307a.gif >=20 > and we see the estimate from the noise map is in the right > ballpark. >=20 > Markus wrote (in a nearby thread): >=20 > > saw practically nothing here on 29.499 last night. >=20 > Signal level from Bob is lower. NAA maintains normal level. >=20 > > are you continuously saving all raw data from your VLF loops? >=20 > Only the lower 24 kHz of 3 channels (2xH + vertical E) are > saved raw=2C spectrum data is saved for 0 to 96kHz. Storage of > the timestamped flac-compressed data is not too onerous=2C at > the last count it was heading for 18 Tbytes. >=20 > Hard disks are big and cheap these days fortunately. > Also reliable too=2C in the last 3 years I've only had one disk > error (which was revealed by md5 checksum verification) which > turned out to be a single bit flip in one byte of one file. >=20 > I strongly recommend recording signals to disk and doing signal > analysis by post-processing. Then you don't miss anything > and you don't have to guess in advance the optimum antenna > pointing=2C spectrogram settings=2C and so on. It is easy to > keep a cache of 10 days or a month of signal. The fact is=2C > almost always you get to hear about interesting things *after* > they've happened=2C especially with natural radio events. > You really are very limited and will miss a lot if you only > work with real time signals. >=20 > -- > Paul Nicholson > -- >=20 = --_8a365b8e-09d1-4360-8ae5-ec218de85aec_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Paul=3B
Wonder what effects s= oil conductivity =3Bchanges has on the propagation at these VLF freqs??=  =3B Temperature here =3Bthis pasted week has been and averaged&nbs= p=3B 4-8 F degrees. =3B Yesterday and last night temp climbed to 40+F!&= nbsp=3B It is a fact that the conductivity in this region =3Bchanges dr= astically with temperature. =3B Much higher with freezing temps. = =3B Usual conductivity of 3-4 at above freezing and upwards of 10-15 with c= old temperatures-the colder the higher the =3Bconductivity-Bob
 = =3B
>=3B Date: Sat=2C 8 Mar 2014 13:37:16 +0000
>=3B From: v= lf0403@abelian.org
>=3B To: rsgb_lf_group@blacksheep.org
>=3B Sub= ject: Re: LF: Daytime 29.499 kHz
>=3B
>=3B Here is the backgroun= d noise diurnal for 2013 at 29.5kHz
>=3B
>=3B http://abelian.o= rg/vlf/tmp/29499_noise_2013.png
>=3B
>=3B The noise is averaged = over a 500Hz band and converted to units
>=3B of fT per root Hz.
&g= t=3B
>=3B The noise is before sferic blanking. Divide the noise
= >=3B amplitude by 10 to estimate the noise after blanking.
>=3B
= >=3B Multiply the noise amplitude by the square root of your
>=3B ba= ndwidth to obtain your RMS noise floor. Or instead=2C divide
>=3B the= noise by the square root of your Fourier transform width
>=3B in seco= nds.
>=3B
>=3B For example=2C from the plot the noise during the= night in early
>=3B March is in the purple but on poor nights has a h= int of red.
>=3B Lets say a bad night then is 15 fT/root(Hz).
>= =3B
>=3B After blanking that would be 1.5 fT=2C and in a 600 second F= ourier
>=3B transform the floor would be 1.5/sqrt(600) =3D 0.06 fT in = each
>=3B Fourier bin.
>=3B
>=3B Compare that with the nois= e level between 19:00 and 21:00 in
>=3B
>=3B http://abelian.or= g/vlf/tmp/29499_140307a.gif
>=3B
>=3B and we see the estimate fr= om the noise map is in the right
>=3B ballpark.
>=3B
>=3B M= arkus wrote (in a nearby thread):
>=3B
>=3B >=3B saw practica= lly nothing here on 29.499 last night.
>=3B
>=3B Signal level fr= om Bob is lower. NAA maintains normal level.
>=3B
>=3B >=3B= are you continuously saving all raw data from your VLF loops?
>=3B >=3B Only the lower 24 kHz of 3 channels (2xH + vertical E) are
>= =3B saved raw=2C spectrum data is saved for 0 to 96kHz. Storage of
>= =3B the timestamped flac-compressed data is not too onerous=2C at
>=3B= the last count it was heading for 18 Tbytes.
>=3B
>=3B Hard dis= ks are big and cheap these days fortunately.
>=3B Also reliable too=2C= in the last 3 years I've only had one disk
>=3B error (which was reve= aled by md5 checksum verification) which
>=3B turned out to be a singl= e bit flip in one byte of one file.
>=3B
>=3B I strongly recomme= nd recording signals to disk and doing signal
>=3B analysis by post-pr= ocessing. Then you don't miss anything
>=3B and you don't have to gue= ss in advance the optimum antenna
>=3B pointing=2C spectrogram setting= s=2C and so on. It is easy to
>=3B keep a cache of 10 days or a mont= h of signal. The fact is=2C
>=3B almost always you get to hear about = interesting things *after*
>=3B they've happened=2C especially with na= tural radio events.
>=3B You really are very limited and will miss a l= ot if you only
>=3B work with real time signals.
>=3B
>=3B = --
>=3B Paul Nicholson
>=3B --
>=3B
= --_8a365b8e-09d1-4360-8ae5-ec218de85aec_--