Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w0MN6ipd026647 for ; Tue, 23 Jan 2018 00:06:45 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1edl4l-0001vF-4J for rs_out_1@blacksheep.org; Mon, 22 Jan 2018 23:00:27 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1edl4I-0001v1-D0 for rsgb_lf_group@blacksheep.org; Mon, 22 Jan 2018 22:59:58 +0000 Received: from mail-oi0-x235.google.com ([2607:f8b0:4003:c06::235]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1edl4D-0006qB-Gj for rsgb_lf_group@blacksheep.org; Mon, 22 Jan 2018 22:59:55 +0000 Received: by mail-oi0-x235.google.com with SMTP id a184so7172115oif.7 for ; Mon, 22 Jan 2018 14:59:53 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=Pp4sngGDYze+8cw9r/j1aoIrJWrh7OZni3nkpo8Q9hE=; b=I3y2aFM7EHtrkVnZZXAtyqBmob40INxqO7q2sKSAmb2UQJcKnISKW1mK61GewtW5Jo cM8WmvMymCKB8shkxZ981Mq3nSJCpvcJw0ih9GA/1t6ETwZicNDA2KDWXbHmnv5ipvUS y1FXQBAkT8/PXyJfjvdUXsAbfBqZdR9pBzcr0d9pzSlMJ8SVCyLeiWC+oW17LxC4Oe71 hplrifdU80lFmNrybIsAA9OSsoriJBuq/VPjIrmFDalrgw2hF8E9dB2Pbg3LGODjib9T JYzATcPQFRYRzs9c/VUtiNJAfhUH70ObMGjWPUrA4GM8LObcWdu/s8s4GkhclfvOYMm3 xnEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=Pp4sngGDYze+8cw9r/j1aoIrJWrh7OZni3nkpo8Q9hE=; b=DWhoSYgAT7bV/vF+2W3khiq603B3UXAgq+ziyWIK0anfgernpC35m+HgLLfDpMx149 6KG51kxMj0m5pTjIhjQMxEXU0Zqt5uA5QImt6a0A3xOrNiiiblxs5PZhRSpYZBG7bedi YVIqf7reJzTVy2Kx/VWovUIgJObzrsxhEzwytUjMFH49JeWeLGuhHx6/3bAWCEJZflgh rkHe+kk+lkYymjuiMXFIVub1IQ2S5qPBvv0SM80q2ZhojvrMnwn7wNIXizikl+cxVhnQ ufevGGxzbo6g6I7e3Wwz3Loye0pR7ivgho/TXnz84+0xlCjNd5JYi2Aov0yVFWE3kG7r E2HQ== X-Gm-Message-State: AKwxyteghI++PucKqbNi+VNbOHJHLTrKidnjXOoYRzCiIsFP9FcZhV/b QuqvBCuyJjYjG44sQp1k3PlNOPO6Fh1ZDGaztjwQYA== X-Google-Smtp-Source: AH8x226k4e8rAY+1E7Rw4yRx2BKBPU/ah3o16SJ+20KNIy46MZX1uMbGPKByfknxDcgKXxJCnIShxpOM6vUlerLHdfE= X-Received: by 10.202.173.212 with SMTP id w203mr4635624oie.149.1516661991312; Mon, 22 Jan 2018 14:59:51 -0800 (PST) MIME-Version: 1.0 Received: by 10.157.37.235 with HTTP; Mon, 22 Jan 2018 14:59:50 -0800 (PST) In-Reply-To: References: <7553d9d1-2639-3846-feb9-7bffc4585597@btinternet.com> From: Roger Lapthorn Date: Mon, 22 Jan 2018 22:59:50 +0000 Message-ID: To: "rsgb_lf_group@blacksheep.org" X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hi All, Best DX on 136kHz WSPR RX here earlier was G8HUH (250km) in Somerset. Nothing spotted since teatime, but my setup could not be much worse! Next year I may well try a miniwhip. Years ago I tried looking for my very low ERP 136kHz QRSS3 with a magmounted miniwhip on the car. As I recall I could copy it the far side of Cambridge (20km?) so I just gave up. At the time I was amazed. I think this was with just my earth-electrode antenna in the ground. Maybe I should try the earth-electrode antenna at this QTH on 136kHz WSPR RX. It really worked well. I think it acted as a loop. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (rogerlapthorn[at]gmail.com) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 8ac9f0a1bced50a7ada6578ede3fb6ae Subject: Re: LF: 136kHz - this is how badmy system is! Content-Type: multipart/alternative; boundary="001a113ce4dc3c95b20563656377" 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, 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 --001a113ce4dc3c95b20563656377 Content-Type: text/plain; charset="UTF-8" Hi All, Best DX on 136kHz WSPR RX here earlier was G8HUH (250km) in Somerset. Nothing spotted since teatime, but my setup could not be much worse! Next year I may well try a miniwhip. Years ago I tried looking for my very low ERP 136kHz QRSS3 with a magmounted miniwhip on the car. As I recall I could copy it the far side of Cambridge (20km?) so I just gave up. At the time I was amazed. I think this was with just my earth-electrode antenna in the ground. Maybe I should try the earth-electrode antenna at this QTH on 136kHz WSPR RX. It really worked well. I think it acted as a loop. Sadly, I think my health is not up to doing field tests these days. I really enjoyed experimenting with "over the horizon" 481THz light. This has been on the back boiler now for almost 5 years. 73s Roger G3XBM On 22 January 2018 at 20:31, Andy Talbot wrote: > Noise power is proportional to bandwidth > At room temperature, a resistor will develop -174dBm of thermal noise or > -174dBm/Hz In a 2.5kHz SSB bandwidth, the total power is therefore -174 + > 10.LOG(2500) = -140dBm > > When using an SDR + waterfall with 0.3Hz bins, the thermal noise per bin, > and the minimum possible sensitivity is -174 + 10.LOG(0.3) = = -179dBm. > Using QRSSS with a 0.01Hz bin, that becomes -194dBm > > Using the bin size of an FFT as the bandwidth is not strictly the case as > FFTs are windowed to increase dynamic range, which has the effect of a > signal appearing in adjacent bins at reduced power. So a good average to > assume if you don't know the exact windowing function is that bandwidth is > twice the bin size. > > Andy G4JNT > > On 22 January 2018 at 20:06, Martin Evans wrote: > >> >> Alan - thanks for this. >> Being a bear of very little brain ( I wouldn't recognise a Newton if I >> tripped over one!) much of your explanation goes over my head, but I >> understand well enough your conclusion that "that is not bad". >> >> One thing that I don't understand is the relevance of bandwidth to an SDR >> receiver. >> >> If I short my receiver input, my baseline stands at -140dB ( that's the >> lowest that the spectrum display goes); connect my antenna and my >> background noise level around 137kHz is around -120dB; DCF30 is around >> -70dB at the moment, and if I increase my scan width, R4 on 198kHz is >> -40dB. All these measurements are taken from the spectrum display in the >> Elad software. >> >> I don't see where bandwidth comes into the picture(!!) >> >> No doubt one of these days some of this will begin to make sense.... >> >> Thanks again, >> >> Martin GW3UCJ. >> >> ******************** >> >> Hi Martin, I would estimate the field strength from DCF39 in your area is >>> about 0.5mV/m (from measurements done by PA0SE in the UK) and from your >>> data that gives about 1.5uV at the RX input as the level of the noise. If >>> that is in an SSB bandwidth that is not bad. I remember the noise plotted >>> on my CFH measurements in around 2002 was in this area but in a 300Hz bw, >>> on the AOR7030 (Remembering WSPR s/n is related to a 2.3kHz bw if I >>> remember right) >>> My minimum signal detection using a waterfall on the audio was 5nV (rx >>> bw not relevant) but 0.3Hz bin size using a good sig-gen. I guess this was >>> little more than 1 to 1.5dB above the noise. I think it was probably >>> quieter here in East Anglia 15 years ago than it i now. >>> >>> I hope that helps (saves you ripping your station apart :-)) ) >>> Alan >>> G3NYK >>> >>> ----- Original Message ----- From: "Martin Evans" >> > >>> To: >>> Sent: Monday, January 22, 2018 4:51 PM >>> Subject: Re: LF: 136kHz - this is how badmy system is! >>> >>> >>> >>>> Watching Roger's adventures on 136kHz, I thought I'd go take a look and >>>> I wondered - >>>> >>>> DCF39 is about 50dB above the noise at 16:44UTC. >>>> >>>> I'm using a 150ft inverted L, untuned, stuffed directly into an Elad >>>> FDM-S2 SDR. >>>> >>>> Decoded G3XIZ, G4FTC, G8HUH & G4GIR between 16:12 and 16:44. >>>> >>>> What does this say about my setup? >>>> >>>> Is it deaf/average/ok? >>>> >>>> How far above the noise is DCF39 in an optimised "good" setup? >>>> >>>> Anyone tell me? >>>> >>>> Martin GW3UCJ Swansea. >>>> >>>> >>> >>> >> >> > --001a113ce4dc3c95b20563656377 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi All,

Best DX on 136kHz WS= PR RX here earlier was G8HUH (250km) in Somerset. Nothing spotted since tea= time, but my setup could not be much worse! Next year I may well try a mini= whip.=C2=A0

Years ago I tried looking for my very= low ERP 136kHz QRSS3 with a magmounted miniwhip on the car. As I recall I = could copy it the far side of Cambridge (20km?) so I just gave up. At the t= ime I was amazed.=C2=A0 I think this was with just my earth-electrode anten= na in the ground. Maybe I should try the earth-electrode antenna at this QT= H on 136kHz WSPR RX. It really worked well. I think it acted as a loop.

Sadly, I think my health is not up to doing field tes= ts these days. I really enjoyed experimenting with "over the horizon&q= uot; 481THz light. This has been on the back boiler now for almost 5 years.=

73s
Roger G3XBM

On 22 January 2018 at 20:31, Andy T= albot <andy.g4jnt@gmail.com> wrote:
Noise power is proportional to bandwidthAt room temperature, a resistor will develop -174dBm of thermal noise or -= 174dBm/Hz=C2=A0 =C2=A0In a 2.5kHz SSB bandwidth, the total power is therefo= re -174 + 10.LOG(2500) =3D -140dBm

When using an S= DR + waterfall with 0.3Hz bins, the thermal noise per bin, and=C2=A0 the mi= nimum possible sensitivity is -174 + 10.LOG(0.3) =3D =3D -179dBm.=C2=A0 =C2= =A0Using QRSSS with a 0.01Hz bin, that becomes -194dBm

=
Using the bin size of an FFT as the bandwidth is not strictly the case= as FFTs are windowed to increase dynamic range, which has the effect of a = signal appearing in adjacent bins at reduced power.=C2=A0 So a good average= to assume if you don't know the exact windowing function is that=C2=A0= bandwidth is twice the bin size.

Andy=C2=A0 G4JNT=

On 22 January 2018 at 20:06, Martin Evans <gw3ucj@btinternet.com> wrote:

Alan - thanks for this.
Being a bear of very little brain ( I wouldn't recognise a Newton if I = tripped over one!) much of your explanation goes over my head, but I unders= tand well enough your conclusion that "that is not bad".

One thing that I don't understand is the relevance of bandwidth to an S= DR receiver.

If I short my receiver input, my baseline stands at -140dB ( that's the= lowest that the spectrum display goes); connect my antenna and my backgrou= nd noise level around 137kHz is around -120dB; DCF30 is around -70dB at the= moment, and if I increase my scan width, R4 on 198kHz is -40dB. All these = measurements are taken from the spectrum display in the Elad software.

I don't see where bandwidth comes into the picture(!!)

No doubt one of these days some of this will begin to make sense....

Thanks again,

Martin GW3UCJ.

********************
Hi Martin, I would estimate the field strength from DCF39 in your area is a= bout 0.5mV/m (from measurements done by PA0SE in the UK) and from your data= that gives about 1.5uV at the RX input as the level of the noise. If that = is in an SSB bandwidth that is not bad. I remember the noise plotted on my = CFH measurements in around 2002 was in this area but in a 300Hz bw, on the = AOR7030 (Remembering WSPR s/n is related to a 2.3kHz bw if I remember right= )
My minimum signal detection using a waterfall on the audio was 5nV (rx bw n= ot relevant) but 0.3Hz bin size using a good sig-gen. I guess this was litt= le more than 1 to 1.5dB above the noise. I think it was probably quieter he= re in East Anglia 15 years ago than it i now.

I hope that helps (saves you ripping your station apart :-))=C2=A0 )
Alan
G3NYK

----- Original Message ----- From: "Martin Evans" <gw3ucj@btinternet.com&g= t;
To: <r= sgb_lf_group@blacksheep.org>
Sent: Monday, January 22, 2018 4:51 PM
Subject: Re: LF: 136kHz - this is how badmy system is!



Watching Roger's adventures on 136kHz, I thought I'd go take a look= and I wondered -

DCF39 is about 50dB above the noise at 16:44UTC.

I'm using a 150ft inverted L, untuned, stuffed directly into an Elad FD= M-S2 SDR.

Decoded G3XIZ, G4FTC, G8HUH & G4GIR between 16:12 and 16:44.

What does this say about my setup?

Is it deaf/average/ok?

How far above the noise is DCF39 in an optimised "good" setup?
Anyone tell me?

Martin GW3UCJ Swansea.







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