Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mh06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 6677338000094; Sun, 7 Aug 2011 18:24:01 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QqBkf-0007zy-PS for rs_out_1@blacksheep.org; Sun, 07 Aug 2011 23:23:21 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QqBke-0007zp-UJ for rsgb_lf_group@blacksheep.org; Sun, 07 Aug 2011 23:23:20 +0100 Received: from mail-ey0-f173.google.com ([209.85.215.173]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QqBkc-0000oa-4Z for rsgb_lf_group@blacksheep.org; Sun, 07 Aug 2011 23:23:20 +0100 Received: by eyb7 with SMTP id 7so3289302eyb.4 for ; Sun, 07 Aug 2011 15:23:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=message-id:from:to:subject:date:mime-version:content-type :x-priority:x-msmail-priority:importance:x-mailer:x-mimeole; bh=o9yFk3MYCyzDQ2eZqwsq6H5iV6nG7BDBHpxp449a3OQ=; b=UWf3TcF3XKF26LLUIIulkljJHK3/lw0wZd25wVsnK7FhnoAcUuKcv2kes8ExQzYTV9 5eEcxKqU+2lZ2kVrDskHBw1o8GroUtpIXfkYP+612gW2Re9ZFJcAXVsHNdHvwgEaWbHa 8jhQngYUa+7fkAbZyaw6m4XO+OjJ7qlHA3wmg= Received: by 10.213.33.79 with SMTP id g15mr775145ebd.39.1312755792455; Sun, 07 Aug 2011 15:23:12 -0700 (PDT) Received: from PcMinto (h50208.upc-h.chello.nl [62.194.50.208]) by mx.google.com with ESMTPS id u16sm2224815eeh.32.2011.08.07.15.23.11 (version=SSLv3 cipher=OTHER); Sun, 07 Aug 2011 15:23:11 -0700 (PDT) Message-ID: From: Minto Witteveen To: Date: Mon, 8 Aug 2011 00:23:04 +0200 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 15.4.3538.513 X-MimeOLE: Produced By Microsoft MimeOLE V15.4.3538.513 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: Re: CW sked on 137 friday morning? Content-Type: multipart/alternative; boundary="----=_NextPart_000_018E_01CC5561.572C9530" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, MISSING_OUTLOOK_NAME 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-SCORE: 0:2:451800768:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m023.1 ; domain : gmail.com DKIM : fail x-aol-sid: 3039ac1d60da4e3f10806f5b X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_018E_01CC5561.572C9530 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Did I write =E2=80=98manual AGC=E2=80=99 ? Obviously I meant to write manual (IF) gain control. Minto pa3bca -------------------------------------------------------------------------= - Ceterum censeo Carthaginem delendam esse From: Minto Witteveen=20 Sent: Monday, August 08, 2011 00:20 To: rsgb_lf_group@blacksheep.org=20 Subject: Re: CW sked on 137 friday morning? Hi Stefan, Let me try to explain a bit better what I have done. When I disable the = AGC of the FT897 I need to dial-down the manual AGC in order to avoid = overloading the IF AND the AF sections when tuned to DCF39. (If I = don=E2=80=99t DCF39 sounds horribly distorted). With this setting I = measure the LF output of the 879 with Speclab. With the same manual AGC setting I tune to say 137.700 and measure the = LF output again with Speclab. But because the manual AGC is dialed down = significantly the band noise =E2=80=98drops through=E2=80=99 the noise = floor of the FT897. So this method is unusable to determine the strenght = of DCF39 w.r.t. to the noise. If I dial up the AGC (or set it on auto again) the noise floor increases = with about 10 dB when I connect the antenna, I think this should be = enough.. By the way, this moment I can not only see your CQ with Speclab, but = with headphones I can even hear you. Regards, Minto pa3bca -------------------------------------------------------------------------= - Ceterum censeo Carthaginem delendam esse From: Stefan Sch=C3=A4fer=20 Sent: Sunday, August 07, 2011 23:29 To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Re: CW sked on 137 friday morning? Hi Minto, Am 07.08.2011 22:57, schrieb Minto Witteveen:=20 Hi Stefan, DCF39 is more than 40 dB above the noise, but the problem is that my = FT897 only seems to have 40 dB dynamic range without the AGC. (range = between the receiver noise floor, and max LF output before the signal = gets distorted). The noise floor without an antenna connected? Then you would need a = other RX or a narrow band (high Q coils) band pass filter. If it is the = noise with an antenna connected, try to find local noise sources!=20 Actually i cannot imagine 40 dB dynamic range so i think the antenna is = connected.. With the AGC it is much more of course, but then I cannot use the LF = output to measure the dB=E2=80=99s between the band noise and DCF39. I = will need to calibrate my S-meter sometimes=E2=80=A6 But based on what I = know about the S-meter, I guestimate that DCF39 is more than 60 dB above = the noise floor (but probably not by much). Wrt to the Speclab settings: I have everything still on the default = settings (just installed it, selected QRSS3 and a suitable frequency = range). But the FFT tab says: Effect of FFT settings with fs=3D 11.0250 kHz: Width of one FFT-bin: 336.456 mHz Equiv. noise bandwidth: 504.684 mHz Max freq range: 0.00000 Hz .. 5.51250 kHz FFT window time: 2.972 s Overlap from scroll interval: 50.0 % 336 mHz is OK too. I prefer 448 but it's a personal taste. I like sharp = limited signs, not the fuzzy ones ;-) If you have suggestions for improved settings I am very interested. I = definitely need to read up on the math behind the FFT settings (and = possibly RTFM hi) Oh, i've forgotten about all the maths i learned about FFT too. It's 10 = years ago and i never needed it again. I'm an appliance operator, you = know ;-) An improvement, especially if you are bothered by DCF-39 will be the = noise blanker! I'll send you a USR file that you can load in SL in a = personal mail. By the way, the noise (man-made QRM) is now much lower than it was = this afternoon. So this tells you you have to do some tests where the local noise floor = comes from! Probably you can gain 20 dB S/N by that! 73, GL, Stefan I saw =E2=80=93 but could not hear - your CQ an hour ago, see = attachment. Using the TS130 so the receiver is still a bit off. Pity I can=E2=80=99t TX =E2=80=A6 L Regards, Minto pa3bca From: Stefan Sch=C3=A4fer=20 Sent: Sunday, August 07, 2011 18:37 To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Re: CW sked on 137 friday morning? Hello Minto,=20 Nice to read about your progress! Am 07.08.2011 18:06, schrieb Minto Witteveen:=20 Hi Stefan,=20 I noticed I wrote ALC, but obviously this must be AGC=E2=80=A6.=20 I installed Speclab, and did some tests with the 879. With the ACG = off I adjusted the gain just to the threshold of (audible) distortion of = the DCF39 signal (500 Hz filter) and read-out the level in Speclab. = Then I dialed to 137.700 and read out the (average) noise level. This = turned out to be a 40 dB lower, however I could hear NO bandnoise at = this setting of the manual AGC=E2=80=A6 only the receiver noise.=20 So DCF-39 would just be 40 dB above the noise? This is much to low. At = least 30 dB would be missed i estimate. But what was the FFT setting "width of one FFT bin" in the FFT = register card?=20 From this I inferred two things:=20 A. DCF39 is more than 40 dB above the noise (but how much I cannot = measure with this method)=20 B. The 879 is a really lousy receiver (But I already knew that)=20 But: there is also good news! I did see (but not hear) your CQ at = 17:40 HR CET, see attached screenshot. My first RX on 137! Congrats to your first LF reception! And it shows me that my calls are = not only for my pleasure :-) So here we may better estimate how many dBs = are missed. Looks like you choosed a relative broad BW for the FFT = settings. 488 (some use 366 mHz) mHz would be a better choice. And i = assume you don't use a noise blanker so far. This will improve thing = too! So at least the receiver + software works.=20 In the screenshot you can see your first CQ recorded with the FT897. = At 17:32 I switched to the TS130. At first glance the signal looks = better on the TS130. Also notice that this trace is a bit off-frequency = and drifts visibly. The 130 has an analog VFO, and the frequency readout = is in 100 Hz steps. The drift might also be attributable to the SA612 = mixer I use (now with a 10 MHz xtal)=20 This proves that at least QRSS3 QSO=E2=80=99s will be possible, so I = have no excuse not finishing my PA and variometer.=20 Yes! :-) How do you go on improving the RX system? Ah, i have an idea: Display = the whole band, as broad as the SSB filter permits. Use a slow scrolling = spectrogram and make your local noise visible. Normally local QRM = sources disappear and appear from time to time. And they could be band = limited. You should see the band noise ideally and its minimum just after the = local sunrise and a few hours later... If that all is on an equal level, = it must be covered by local noise!=20 Try to run the PA0RDT on batteries and your TRX and PC as well = (netbook). Do not change the antenna position and see how and if the = noise is changing and so on... :-) 73, Stefan/DK7FC ------=_NextPart_000_018E_01CC5561.572C9530 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Did I write =E2=80=98manual AGC=E2=80=99 ?
Obviously I meant to write manual (IF) gain control.
 
Minto pa3bca
 
 
-------------------------------------------------------------------= -------
Ceterum=20 censeo Carthaginem delendam esse
 
Sent: Monday, August 08, 2011 00:20
Subject: Re: CW sked on 137 friday = morning?
 

Hi = Stefan,

Let me try to explain a = bit better=20 what I have done. When I disable the AGC of the FT897 I need to = dial-down the=20 manual AGC in order to avoid overloading the IF AND the AF sections when = tuned=20 to DCF39. (If I don=E2=80=99t  DCF39 sounds=20 horribly distorted). With this setting I measure the LF output of the = 879 with=20 Speclab.
With the same manual AGC setting I tune to say 137.700 and = measure=20 the LF output again with Speclab. But because the manual AGC is dialed = down=20 significantly the band noise =E2=80=98drops through=E2=80=99 the noise = floor of the FT897. So=20 this method is unusable to determine the strenght of DCF39 w.r.t. to the = noise.

If I dial up the AGC (or = set it on=20 auto again) the noise floor increases with about 10 dB when I connect = the=20 antenna, I think this should be enough..

By the way, this moment I = can not=20 only see your CQ with Speclab, but with headphones I can even hear=20 you.

Regards,
Minto=20 pa3bca

 
-------------------------------------------------------------------= -------
Ceterum=20 censeo Carthaginem delendam esse
 
From: Stefan Sch=C3=A4fer =
Sent: Sunday, August 07, 2011 23:29
Subject: Re: LF: Re: CW sked on 137 friday=20 morning?
 
Hi=20 Minto,

Am 07.08.2011 22:57, schrieb Minto Witteveen:=20

Hi Stefan,

DCF39 is more than 40 dB above the noise, but the = problem is that=20 my FT897 only seems to have 40 dB dynamic range without the AGC. = (range=20 between the receiver noise floor, and max LF output before the signal = gets=20 distorted).

The noise = floor=20 without an antenna connected? Then you would need a other RX or a narrow = band=20 (high Q coils) band pass filter. If it is the noise with an antenna = connected,=20 try to find local noise sources!
Actually i cannot imagine 40 dB = dynamic=20 range so i think the antenna is connected..

  With the AGC it is much more of = course, but=20 then I cannot use the LF output to measure the dB=E2=80=99s between = the band noise and=20 DCF39. I will need to calibrate my S-meter sometimes=E2=80=A6 But = based on what I know=20 about the S-meter, I guestimate that DCF39 is more than 60 dB above = the noise=20 floor (but probably not by much).
Wrt to the =  Speclab=20 settings: I have everything still on the default settings (just = installed it,=20 selected QRSS3 and a suitable frequency range). But the FFT tab=20 says:

Effect of FFT settings with fs=3D 11.0250 kHz:
Width = of one=20 FFT-bin: 336.456 mHz
Equiv. noise bandwidth: 504.684 mHz
Max = freq range:=20 0.00000 Hz .. 5.51250 kHz
FFT window time: 2.972 s
Overlap from = scroll=20 interval: 50.0 %

336 = mHz is OK=20 too. I prefer 448 but it's a personal taste. I like sharp limited signs, = not the=20 fuzzy ones ;-)

If you have suggestions for improved settings I am very = interested. I definitely need to read up on the math behind the FFT = settings=20 (and possibly RTFM = hi)

Oh,=20 i've forgotten about all the maths i learned about FFT too. It's 10 = years ago=20 and i never needed it again. I'm an appliance operator, you know = ;-)
An=20 improvement, especially if you are bothered by DCF-39 will be the noise = blanker!=20 I'll send you a USR file that you can load in SL in a personal mail.

By the way, the noise (man-made QRM) is now much lower = than it=20 was this afternoon.

So = this=20 tells you you have to do some tests where the local noise floor comes = from!=20 Probably you can gain 20 dB S/N by that!

73, GL,=20 Stefan




 I saw =E2=80=93 but could not hear - =  your CQ an hour ago, see attachment. Using the = TS130 so the=20 receiver is still a bit off.
Pity I can=E2=80=99t TX =E2=80=A6 = L

Regards,
Minto = pa3bca

 
Sent: Sunday, August 07, 2011 18:37
Subject: Re: LF: Re: CW sked on 137 friday=20 morning?
 
Hello=20 Minto,

Nice to read about your progress!

Am 07.08.2011 = 18:06,=20 schrieb Minto Witteveen:=20
Hi=20 Stefan,

I noticed I wrote ALC, but obviously this must be = AGC=E2=80=A6.=20
I  installed Speclab, and did some tests with the 879. With = the ACG=20 off I adjusted the gain just to the threshold of (audible) = distortion of the=20 DCF39 signal (500 Hz filter) and read-out the level  in = Speclab. Then I=20 dialed to 137.700 and read out the (average) noise level. This = turned out to=20 be a 40 dB lower, however I could hear NO bandnoise at this setting = of the=20 manual AGC=E2=80=A6  only the receiver noise. =
So DCF-39 would=20 just be 40 dB above the noise? This is much to low. At least 30 dB = would be=20 missed i estimate.
But what was the FFT setting "width of one FFT = bin" in=20 the FFT register card?
From this I inferred two things: =
A.=20 DCF39 is more than 40 dB above the noise (but how much I cannot = measure with=20 this method)
B. The 879 is a really lousy receiver (But I = already knew=20 that)

But: there is also good news! I did see (but not hear) = your CQ=20 at 17:40 HR CET, see attached screenshot. My first RX on=20 137!

Congrats to your first LF reception! And = it shows=20 me that my calls are not only for my pleasure :-) So here we may = better=20 estimate how many dBs are missed. Looks like you choosed a relative = broad BW=20 for the FFT settings. 488 (some use 366 mHz) mHz would be a better = choice. And=20 i assume you don't use a noise blanker so far. This will improve thing = too!

So=20 at least the receiver + software works.
In the screenshot you = can see=20 your first CQ recorded with the FT897. At 17:32 I switched to the = TS130. At=20 first glance the signal looks better on the TS130. Also notice that = this=20 trace is a bit off-frequency and drifts visibly. The 130 has an = analog VFO,=20 and the frequency readout is in 100 Hz steps. The drift might also = be=20 attributable to the SA612 mixer I use (now with a 10 MHz xtal) =

This=20 proves that at least QRSS3 QSO=E2=80=99s will be possible, so I have = no excuse not=20 finishing my PA and variometer.
Yes! :-)
How do = you go on=20 improving the RX system? Ah, i have an idea: Display the whole band, = as broad=20 as the SSB filter permits. Use a slow scrolling spectrogram and make = your=20 local noise visible. Normally local QRM sources disappear and appear = from time=20 to time. And they could be band limited.
You should see the band = noise=20 ideally and its minimum just after the local sunrise and a few hours = later...=20 If that all is on an equal level, it must be covered by local noise! =
Try=20 to run the PA0RDT on batteries and your TRX and PC as well (netbook). = Do not=20 change the antenna position and see how and if the noise is changing = and so=20 on... :-)

73, Stefan/DK7FC
 
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