Return-Path: Received: from mtain-dk03.r1000.mx.aol.com (mtain-dk03.r1000.mx.aol.com [172.29.180.7]) by air-md03.mail.aol.com (v129.4) with ESMTP id MAILINMD034-8b7f4d713b35242; Fri, 04 Mar 2011 14:19:17 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dk03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 708C838000110; Fri, 4 Mar 2011 14:19:15 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PvaW4-0007pa-Ec for rs_out_1@blacksheep.org; Fri, 04 Mar 2011 19:18:20 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PvaW3-0007pR-LI for rsgb_lf_group@blacksheep.org; Fri, 04 Mar 2011 19:18:19 +0000 Received: from mail-pv0-f171.google.com ([74.125.83.171]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PvaW0-0001Ag-3r for rsgb_lf_group@blacksheep.org; Fri, 04 Mar 2011 19:18:19 +0000 Received: by pva4 with SMTP id 4so460437pva.16 for ; Fri, 04 Mar 2011 11:18:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:date:message-id:subject:from:to :content-type; bh=n+Adk4ECbd9WKAaWNFDT6jyiGdQE9oge8o1mW7yQCNE=; b=Xf5SIsiS70pWJLT1HcccJxZPre/N94eUhlw6aV2LnawLXCaM6/Z4/9j3uDMb2Pwtvc X3Cp1Xx8Aq2RgyG8TKZI+SANV3+ySXP8Xs/qU+N0OrEPTC4wuAU2y+cq9G7O3HpsxuhW HNooT7WGpw3n0ElF8cVgBdFoDjgoNpyFEQdiU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=K69OOrFUJGYeHEF29SXf+CPVho/zEgAnYvk4AecX4SjVEyKrKBO1TMcPaf5yMGh57i CMNMZdaUPdOdB0XwYsCQivzM1v8Rc+ZpmOa+0pBVA+zNPLanxes0TjwOwKW9AHq8UAy6 TI34q3oGR/tjW3u1HpOPiTSynlHG6NmnoQg88= MIME-Version: 1.0 Received: by 10.142.195.3 with SMTP id s3mr735474wff.22.1299266288783; Fri, 04 Mar 2011 11:18:08 -0800 (PST) Received: by 10.142.221.15 with HTTP; Fri, 4 Mar 2011 11:18:08 -0800 (PST) Date: Fri, 4 Mar 2011 19:18:08 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: Topband ionogram trace Content-Type: multipart/alternative; boundary=000e0cd28d849c93e2049dad0191 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=HTML_MESSAGE 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-d002.1 ; domain : gmail.com DKIM : fail x-aol-sid: 3039ac1db4074d713b333e3b X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --000e0cd28d849c93e2049dad0191 Content-Type: text/plain; charset=ISO-8859-1 Here's Peter's update on the 'unusual' topband split trace. Might explain its cleanliness Andy www.g4jnt.com ---------- Forwarded message ---------- From: Peter Martinez Date: 4 March 2011 18:35 Subject: Re: Dopplergrams 12 years ago To: Andy Talbot Andy: I had a look at the QRSS sample that G4AYT captured. Around the same time I was watching the signal from the Fairford ionosonde. This sweeps from 1625kHz, through top-band and on up to 13MHz. At that time it was clear that the Fcrit was getting down towards 2MHz so the F-layer was rising rapidly so this would have been responsible for the increasing negative Doppler shift he was seeing on one of the traces. In fact the MUF on the Fairford-Kendal path dropped below 1.7MHz at about 3 am that night. There was also evidence of night-time sporadic-E. This is sometimes known as Auroral sporadic E but it isn't 'auroral' in the sense we usually mean, but refers to patches of Es which drift south from the Auroral oval, probably initiated by the same particle precipitation that causes aurora. This Es activity could have been responsible for the non-Doppler-shifted trace that G4AYT saw. On a normal night only the F-layer would be reflecting on top-band. Fairford now has a new ionosonde equipment, a Digisonde DPS-4D which I find is much easier to 'eavesdrop' on. The Digisondes are pulse sounders with the receiver co-located with the transmitter with the receiver synchronised to the transmitter locally. They didn't need to be locked to anything and they weren't stable. The new one behaves rather better, stepping exactly 25kHz exactly every 640mS (locked to GPS). I have my system stepping in sync and have some crude ionograms already and have confirmed that the pulse timing is accurate and stable. The next job is to implement the pulse-compression algorithm, which is very similar to that used by LORAN C. This will give me real-time ionograms again, a facility I lost when the UK chirpsounders closed down last year. 73 Peter ----- Original Message ----- From: "Andy Talbot" To: Sent: Thursday, March 03, 2011 7:59 PM Subject: Dopplergrams 12 years ago Hi Peter - > Cast your mind back. We did some of the first Dopplergram tests on 1967kHz > back in 1998, and produced the plots shown > > http://www.g4jnt.com/Download/1967jnt1.jpg > http://www.g4jnt.com/Download/1967jnt3.jpg > http://www.g4jnt.com/Download/1967jnt4.jpg > > Can you recall the vertical span on the trace? As far as I recall, your > EVM software decimated from 8kHz, then you set 80% of the samplinbg rate > as plot BW, so 3.125, 6.25Hz etc But t'would be interesting to know for > sure. > > Someone on the LF reflector (see below) has just posted the plot of some > QRSS topband tests, and was "surprised" to see the trace splitting. So I > looked out these to show what was done over a decade ago. > > Andy > > > > On 3 March 2011 18:55, Chris wrote: > > Hi All, >> Yesterday evening Pete, M0FMT, transmitted QRSS on topband for a test. An >> unexpected effect was noticed with the trace splitting in two. Nothing new >> or 'earth shattering' I expect, but new to us and worthy of further >> experimentation. >> See the result and conclusion on my website http://qsl.net/g4ayt on the >> bottom of page 1. >> I have never seen this effect on 137, even with quite strong audible >> signals, maybe others have. >> Vy 73, >> Chris, G4AYT, Whitstable, UK. >> >> > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1204 / Virus Database: 1435/3479 - Release Date: 03/03/11 > --000e0cd28d849c93e2049dad0191 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Here's Peter's update on the 'unusual' topband split= trace.=A0=A0 Might explain its cleanliness
=A0
Andy
=A0
---------- Forwarded message ----------
From: Peter Martinez <peter.martinez@btinternet.com<= /a>>
Date: 4 March 2011 18:35
Subject: Re: Dopplergrams 12 years ago
To:= Andy Talbot <andy.g4jnt@gmail.com>


Andy:

I had a look at the= QRSS sample that G4AYT captured. Around the same time I was watching the= signal from the Fairford ionosonde. This sweeps from 1625kHz, through top= -band and on up to 13MHz. At that time it was clear that the Fcrit was get= ting down towards 2MHz so the F-layer was rising rapidly so this would hav= e been responsible for the increasing negative Doppler shift he was seeing= on one of the traces. In fact the MUF on the Fairford-Kendal path dropped= below 1.7MHz at about 3 am that night. There was also evidence of night-t= ime sporadic-E. This is sometimes known as Auroral sporadic E but it isn&#= 39;t 'auroral' in the sense we usually mean, but refers to patches= of Es which drift south from the Auroral oval, probably initiated by the= same particle precipitation that causes aurora. This Es activity could ha= ve been responsible for the non-Doppler-shifted trace that G4AYT saw. On= a normal night only the F-layer would be reflecting on top-band.

Fairford now has a new ionosonde equipment, a Digisonde DPS-4D which= I find is much easier to 'eavesdrop' on. The Digisondes are pulse= sounders with the receiver co-located with the transmitter with the recei= ver synchronised to the transmitter locally. They didn't need to be lo= cked to anything and they weren't stable. The new one behaves rather= better, stepping exactly 25kHz exactly every 640mS (locked to GPS). I hav= e my system stepping in sync and have some crude ionograms already and hav= e confirmed that the pulse timing is accurate and stable. The next job is= to implement the pulse-compression algorithm, which is very similar to th= at used by LORAN C. =A0This will give me real-time ionograms again, a faci= lity I lost when the UK chirpsounders closed down last year.


73
Peter

----- Original Message ----- From: "A= ndy Talbot" <andy.g4jnt@gmail.com>
To: <peter.martinez@btinternet.com>= ;
Sent: Thursday, March 03, 2011 7:59 PM
Subject: Dopplergrams 12 years= ago


Hi Peter -
Cast your mind back. =A0We did some of the first Dopple= rgram tests on 1967kHz
back in 1998, and produced the plots shown
http://www.g4jnt.com/Download/1967jnt1.jpg
h= ttp://www.g4jnt.com/Download/1967jnt3.jpg
http://www.g4jnt.com/Downl= oad/1967jnt4.jpg

Can you recall the vertical span on the trace? =A0 As far as I recall,= your
EVM software decimated from 8kHz, then you set 80% of the samplin= bg rate
as plot BW, so 3.125, 6.25Hz etc =A0 =A0But t'would be inte= resting to know for
sure.

Someone on the LF reflector (see below) =A0has just posted th= e plot of some
QRSS topband tests, and was "surprised" to see= the trace splitting. =A0So I
looked out these to show what was done ov= er a decade ago.

Andy



On 3 March 2011 18:55, Chris <c.ashby435@btinternet.com> wrote:

=A0Hi All,
Yesterday evenin= g Pete, M0FMT, transmitted QRSS on topband for a test. An
unexpected ef= fect was noticed with the trace splitting in two. Nothing new
or 'earth shattering' I expect, but new to us and worthy of furthe= r
experimentation.
See the result and conclusion on my website http://qsl.net/g4ayt on= the
bottom of page 1.
I have never seen this effect on 137, even with quite= strong audible
signals, maybe others have.
Vy 73,
Chris, G4AYT,= Whitstable, UK.




-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.= 0.1204 / Virus Database: 1435/3479 - Release Date: 03/03/11


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