Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mg01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 20AA1380000BA; Sun, 7 Aug 2011 17:30:08 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QqAuD-0007mK-PP for rs_out_1@blacksheep.org; Sun, 07 Aug 2011 22:29:09 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QqAuD-0007mB-1e for rsgb_lf_group@blacksheep.org; Sun, 07 Aug 2011 22:29:09 +0100 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QqAuC-0008LL-91 for rsgb_lf_group@blacksheep.org; Sun, 07 Aug 2011 22:29:09 +0100 Received: from ix.urz.uni-heidelberg.de (cyrus-portal.urz.uni-heidelberg.de [129.206.100.176]) by relay2.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id p77LT720023605 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 7 Aug 2011 23:29:07 +0200 Received: from extmail.urz.uni-heidelberg.de (extmail.urz.uni-heidelberg.de [129.206.100.140]) by ix.urz.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id p77LT6ss026508 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 7 Aug 2011 23:29:07 +0200 Received: from [129.206.205.128] (vpn205-128.rzuser.uni-heidelberg.de [129.206.205.128]) by extmail.urz.uni-heidelberg.de (8.13.4/8.13.1) with ESMTP id p77LT3OB020268 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 7 Aug 2011 23:29:05 +0200 Message-ID: <4E3F03BA.5020707@iup.uni-heidelberg.de> Date: Sun, 07 Aug 2011 23:29:30 +0200 From: =?UTF-8?B?U3RlZmFuIFNjaMOkZmVy?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.11) Gecko/20100711 Thunderbird/3.0.6 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4E3B1BFD.5090807@iup.uni-heidelberg.de> <4E3B2EA3.90003@iup.uni-heidelberg.de> <26D9EBB1476B467E9E02C10B3FACC2C8@PcMinto> <4E3D54DE.1000202@iup.uni-heidelberg.de> <5D042DA2B0C04AA09C5416113128574C@PcMinto> <4E3E614D.3060409@iup.uni-heidelberg.de> <4E3EBF3F.6090604@iup.uni-heidelberg.de> In-Reply-To: X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Re: CW sked on 137 friday morning? Content-Type: multipart/alternative; boundary="------------070906010604020209070606" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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-SCORE: 0:2:447801504:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d60c94e3f03e03279 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------070906010604020209070606 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay2.uni-heidelberg.de id p77LT720023605 Hi Minto, Am 07.08.2011 22:57, schrieb Minto Witteveen: > > Hi Stefan, > > DCF39 is more than 40 dB above the noise, but the problem is that my=20 > 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=20 > gets distorted). > The noise floor without an antenna connected? Then you would need a=20 other RX or a narrow band (high Q coils) band pass filter. If it is the=20 noise with an antenna connected, try to find local noise sources! Actually i cannot imagine 40 dB dynamic range so i think the antenna is=20 connected.. > > With the AGC it is much more of course, but then I cannot use the LF=20 > output to measure the dB=E2=80=99s between the band noise and DCF39. I = will=20 > need to calibrate my S-meter sometimes=E2=80=A6 But based on what I kno= w about=20 > the S-meter, I guestimate that DCF39 is more than 60 dB above the=20 > noise floor (but probably not by much). > Wrt to the Speclab settings: I have everything still on the default=20 > settings (just installed it, selected QRSS3 and a suitable frequency=20 > 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=20 limited signs, not the fuzzy ones ;-) > > If you have suggestions for improved settings I am very interested. I=20 > definitely need to read up on the math behind the FFT settings (and=20 > possibly RTFM hi) > Oh, i've forgotten about all the maths i learned about FFT too. It's 10=20 years ago and i never needed it again. I'm an appliance operator, you=20 know ;-) An improvement, especially if you are bothered by DCF-39 will be the=20 noise blanker! I'll send you a USR file that you can load in SL in a=20 personal mail. > > By the way, the noise (man-made QRM) is now much lower than it was=20 > this afternoon. > So this tells you you have to do some tests where the local noise floor=20 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 attachmen= t.=20 > 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 > *Sent:* Sunday, August 07, 2011 18:37 > *To:* rsgb_lf_group@blacksheep.org > *Subject:* Re: LF: Re: CW sked on 137 friday morning? > Hello Minto, > > Nice to read about your progress! > > Am 07.08.2011 18:06, schrieb Minto Witteveen: >> Hi Stefan, >> >> I noticed I wrote ALC, but obviously this must be AGC=E2=80=A6. >> 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=20 >> of the DCF39 signal (500 Hz filter) and read-out the level in=20 >> Speclab. Then I dialed to 137.700 and read out the (average) noise=20 >> level. This turned out to be a 40 dB lower, however I could hear NO=20 >> bandnoise at this setting of the manual AGC=E2=80=A6 only the receive= r noise. > So DCF-39 would just be 40 dB above the noise? This is much to low. At=20 > least 30 dB would be missed i estimate. > But what was the FFT setting "width of one FFT bin" in the FFT=20 > register card? >>> From this I inferred two things: >> A. DCF39 is more than 40 dB above the noise (but how much I cannot=20 >> measure with this method) >> B. The 879 is a really lousy receiver (But I already knew that) >> >> But: there is also good news! I did see (but not hear) your CQ at=20 >> 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=20 > are not only for my pleasure :-) So here we may better estimate how=20 > many dBs are missed. Looks like you choosed a relative broad BW for=20 > the FFT settings. 488 (some use 366 mHz) mHz would be a better choice.=20 > And i assume you don't use a noise blanker so far. This will improve=20 > thing too! > >> So at least the receiver + software works. >> In the screenshot you can see your first CQ recorded with the FT897.=20 >> At 17:32 I switched to the TS130. At first glance the signal looks=20 >> better on the TS130. Also notice that this trace is a bit=20 >> off-frequency and drifts visibly. The 130 has an analog VFO, and the=20 >> 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 proves that at least QRSS3 QSO=E2=80=99s will be possible, so I h= ave no=20 >> excuse not finishing my PA and variometer. > Yes! :-) > How do you go on improving the RX system? Ah, i have an idea: Display=20 > the whole band, as broad as the SSB filter permits. Use a slow=20 > scrolling spectrogram and make your local noise visible. Normally=20 > local QRM sources disappear and appear from time to time. And they=20 > could be band limited. > You should see the band noise ideally and its minimum just after the=20 > local sunrise and a few hours later... If that all is on an equal=20 > level, it must be covered by local noise! > Try to run the PA0RDT on batteries and your TRX and PC as well=20 > (netbook). Do not change the antenna position and see how and if the=20 > noise is changing and so on... :-) > > 73, Stefan/DK7FC --------------070906010604020209070606 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay2.uni-heidelberg.de id p77LT720023605 Hi Minto,

Am 07.08.2011 22:57, schrieb Minto Witteveen:

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!
Actually i cannot imagine 40 dB dynamic range so i think the antenna is connected..

=C2=A0 With the AGC it is much = more of course, but then I cannot use the LF output to measure the dB=E2=80=99= s 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 guestima= te that DCF39 is more than 60 dB above the noise floor (but probably not by much).
Wrt to the =C2=A0Speclab settings: I have everyth= ing 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 11.0= 250 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




=C2=A0I saw =E2=80=93 but coul= d not hear - =C2=A0your CQ an hour ago, see attachment. Using the T= S130 so the receiver is still a bit off.
Pity I can=E2=80=99t TX =E2=80=A6 L

Regards,
Minto pa3bca

=C2=A0
From: Stefan Sch=C3=A4fer <= /div>
Sent: Sunday, August 07, 2011 18:37
Subject: Re: LF: Re: CW sked on 137 friday morning?
=C2=A0
Hello Minto,

Nice to read about your progress!

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

I noticed I wrote ALC, but obviously this must be AGC=E2=80=A6.
I=C2=A0 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=C2=A0 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=C2=A0 only the receiver noise.
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?
From this I inferred two things:
A. DCF39 is more than 40 dB above the noise (but how much I cannot measure with this method)
B. The 879 is a really lousy receiver (But I already knew that)

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.
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)

This proves that at least QRSS3 QSO=E2=80=99s will be possible, so I have= no excuse not finishing my PA and variometer.
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!
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
=C2=A0
--------------070906010604020209070606--