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04-03-2013, 14:41
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#46 |
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Registered User
Join Date: Apr 2006
Location: Roswell, Georgia, USA
Posts: 9,635
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BBC 3955 KHz reception near Atlanta, Georgia, USA
The overnight reception report - 0.09% decoded audio, 13.17 dB max SNR.
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73, -Zyg- AF4MP 34°02' N, 84°24' W EM74ta |
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04-03-2013, 15:42
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#47 |
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Registered User
Join Date: Mar 2005
Location: Shizuoka City, Japan
Posts: 9,700
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Zyg,
I think it is difficult to answer your question about how many dBuV gives 100% decoding. When I listened to RRI on 9 MHz last night 30 dBuV seemed to be the limit for good decoding with 20.96 kbps, BBC this morning on 4 MHz failed around 28 dBuV with 16.92 kbps, but then Fading and a bad CIR added up to the loss of audio. On the other hand in the good ol' DRM days when I used to monitor the 80 W Rwanda TX on 25.740 MHz I got audio at RF input levels less than 20 dBuV and even less with 17.46 kbps. A messy Channel Impulse Ratio always results in chopped audio. On 25 MHz I usually got a single, narrow peak in the CIR, not a screen full of clutter like on 6 and 7 MHz in the evenings. A single, distinct peak of little over 10 dB above the noise floor seems to produce audio. If there are 3 peaks or more, then one of the peaks needs to be at least 10 dB above the rest to get any decodeed audio. These observations are just my personal experience over the years. Perhaps other listeners have different opinions? Just now bit eXpress on 16 MHz produced some audio with 11 dB SNR, 19 dBuV running 16.68 kbps. Doppler was a bit higher on BBC this morning. SNR peaked at 30.36 dB and I got 99.22 % CDA. |
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05-03-2013, 13:31
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#48 |
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Registered User
Join Date: Mar 2005
Location: Shizuoka City, Japan
Posts: 9,700
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Woke up late this morning, so only a 28 min. log. Max. SNR was almost 33 dB. 99.79% CDA.
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05-03-2013, 15:14
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#49 |
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Registered User
Join Date: Apr 2006
Location: Roswell, Georgia, USA
Posts: 9,635
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BBC 3955 KHz reception near Atlanta, Georgia, USA
The overnight reception report - 0.37% decoded audio, 14.01 dB max SNR.
Terje, Thank you for the signal strength comments. When using a dipole antenna 30dBuV is about 9 on a properly calibrated s-meter. So the general rule is that decoding is probably possible if the signal strength is greater than S-9.
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73, -Zyg- AF4MP 34°02' N, 84°24' W EM74ta |
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06-03-2013, 13:10
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#50 |
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Registered User
Join Date: Apr 2006
Location: Roswell, Georgia, USA
Posts: 9,635
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BBC 3955 KHz reception near Atlanta, Georgia, USA
The overnight reception report - 0.02% decoded audio, 9.95 dB max SNR.
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73, -Zyg- AF4MP 34°02' N, 84°24' W EM74ta |
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07-03-2013, 09:58
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#51 |
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Registered User
Join Date: Mar 2005
Location: Shizuoka City, Japan
Posts: 9,700
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Perfect, but I don't know why there are 3 re-syncs in the log.
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07-03-2013, 12:36
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#52 |
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Registered User
Join Date: Apr 2006
Location: Roswell, Georgia, USA
Posts: 9,635
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BBC 3955 KHz reception near Atlanta, Georgia, USA
The overnight reception report - no decoded audio, 10.30 dB max SNR.
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73, -Zyg- AF4MP 34°02' N, 84°24' W EM74ta |
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08-03-2013, 13:06
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#53 |
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Registered User
Join Date: Apr 2006
Location: Roswell, Georgia, USA
Posts: 9,635
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BBC 3955 KHz reception near Atlanta, Georgia, USA
The overnight reception report - no decoded audio, 7.43 dB max SNR.
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73, -Zyg- AF4MP 34°02' N, 84°24' W EM74ta |
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08-03-2013, 13:25
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#54 |
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Registered User
Join Date: Mar 2005
Location: Shizuoka City, Japan
Posts: 9,700
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Perfect this morning with 99.81% CDA and SNR peaked at 30.23 dB around 0611. This morning we had -10°C outside. Brrr...
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09-03-2013, 05:29
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#55 |
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Registered User
Join Date: Mar 2012
Location: E Devon Uk
Posts: 286
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Newstar and PKs loop SW620
Good reception here in Bath UK, a few breaks in audio, new battery in SW620 makes big difference even though its not really supposed to work well at these lower frequencies
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09-03-2013, 09:31
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#56 |
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Registered User
Join Date: Mar 2005
Location: Shizuoka City, Japan
Posts: 9,700
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Short log of the last 20 minutes or so. Perfect after one minute at the start.
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09-03-2013, 12:18
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#57 |
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Registered User
Join Date: Apr 2006
Location: Roswell, Georgia, USA
Posts: 9,635
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BBC 3955 KHz reception near Atlanta, Georgia, USA
The overnight reception report - no decoded audio, 8.16 dB max SNR.
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73, -Zyg- AF4MP 34°02' N, 84°24' W EM74ta |
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10-03-2013, 12:41
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#58 |
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Registered User
Join Date: Apr 2006
Location: Roswell, Georgia, USA
Posts: 9,635
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BBC 3955 KHz reception near Atlanta, Georgia, USA
The overnight reception report - no decoded audio, about 5 dB max SNR (the value in the log window is a DReaM spurious spike).
Looks like any reception here is pretty much over until the next propagation season in five or six months.
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73, -Zyg- AF4MP 34°02' N, 84°24' W EM74ta |
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11-03-2013, 17:15
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#59 |
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Registered User
Join Date: Mar 2005
Location: Shizuoka City, Japan
Posts: 9,700
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Perfect reception in this short log.
Last edited by Digger : 11-03-2013 at 20:57. |
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12-03-2013, 11:03
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#60 |
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Registered User
Join Date: Mar 2005
Location: Shizuoka City, Japan
Posts: 9,700
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Perfect reception this morning.
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