RE: LF: RE: Who's playing on 503.7

["Gary - G4WGT" <g4wgt@tiscali.co.uk>]

OK Andy,

 

Yes, they looked the same strength as your main beacon signal.

 

Thanks for the previous mail containing the brief explanation of the SNR feature.

 

73

 

Gary – G4WGT.

 

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From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Andy Talbot
Sent: 18 March 2009 11:24
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: RE: Who's playing on 503.7

 

I sometimes flick the test switch and send a carrier - so you're probably seeing those.

 

Andy  G4JNT
www.g4jnt.com

2009/3/17 Gary - G4WGT <g4wgt@tiscali.co.uk>

Andy,

 

>>>> Did the messages about the modified beacon timing software get though this reflector - don't appear to see them in the in box?

I received the original & the correction to the url.

 

OK, I used “decode” as the first word that came out of my head.

 

I have looked at the black trace on my beacon chart & it doesn’t seem to coincide with the peaks on the blue & green trace, there is a black peak but slightly offset. On my grabber saves there is very high noise level for a couple of minutes some times the blue & green has a peak which shows on the text log as well.

 

But I have also seen very short carriers which I thought at first were part of you normal beacon signal & when looking carefully at the timestamp were at the following times – 1735, 1750 & 1751. At these times there was no burst of noise.

 

Cheers,

 

Gary - G4WGT.

 

 

 

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From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Andy Talbot
Sent: 17 March 2009 20:36

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: RE: Who's playing on 503.7

 

continued ....

 

The black trace gives it away.  If there is extended  QRM that spans  the noise measurement period (which is the WHOLE minute before) and the 5s Tx period it will show up on both.   The different system of noise measurement explains why the (no QRMed) green and blue traces are not sitting on top of teh black trace.   Ideally, with no signal there, they should.

Andy  G4JNT
www.g4jnt.com

2009/3/17 Andy Talbot <andy.g4jnt@googlemail.com>

I filled in a couple at 1800, deliberately, by flicking the test switch on my beacon Tx.   But there are too many peaks on the green annd blue traces to not suspect someone else is firing up a Tx.

 

Its not a case of false decodes - there's not such thing as a 'decode' with this monitoring S/W.   All it does is to measure the signal power over precisely  this time slot, using a synchronised FFT with a bin size of 0.2Hz, which after windowing gives about 0.4Hz noise bandwidth.  So any QRM would have to be quite strong to make a significant impact, and persist over 5 seconds.   Short spikes get  averaged out to not-a-lot.

 

Did the messages about the modified beacon timing software get though this reflector - don't appear to see them in the in box?

 

If not,  http://www.g4jnt.com/beacons.htm at the bottom look for PCBCN

Directly, http://www.g4jnt.com/PCBCN.zip

 

Andy  G4JNT
www.g4jnt.com

2009/3/17 Gary - G4WGT <g4wgt@tiscali.co.uk>

 

Hi Andy, LF,

 

I have not detected anything here other than your Tx.

 

I was going to e-mail anyway because I have some false decodes on the 5 & 6 minute slots, see list below. These coincide with high bursts of noise which I experience here from time to time. Is there an issue with the decode software being “foxed” by high noise level?

 

Gary – G4WGT.

 

15:45  40.35  25.76  -240.0  0.0

15:46  41.05  25.76  -240.0  1499.5

15:47  39.52  25.76  -240.0  0.0

16:00  41.70  25.75  -240.0  1499.5

16:01  41.62  25.75  -240.0  1510.6

16:02  31.49  25.75  -240.0  0.0

16:15  40.10  25.47  -240.0  0.0

16:16  30.16  25.47  -240.0  0.0

16:17  29.17  25.47  -240.0  0.0

16:30  37.85  28.93  -240.0  0.0

16:31  41.80  28.93  -240.0  0.0

16:32  36.23  28.93  -240.0  0.0

16:45  40.98  25.80  -240.0  1499.6

16:46  29.45  25.80  -240.0  0.0

16:47  30.17  25.80  -240.0  0.0

17:00  35.23  25.58  -240.0  0.0

17:01  28.35  25.58  -240.0  0.0

17:02  35.28  25.58  -240.0  0.0

17:15  45.32  25.10  -240.0  1499.4

17:16  30.14  25.10  -240.0  0.0

17:17  27.57  25.10  -240.0  0.0

17:30  51.09  25.30  -240.0  1499.5

17:31  53.16  25.30  -240.0  1499.6

17:32  30.18  25.30  -240.0  0.0

17:45  47.93  25.21  -240.0  1499.5

17:46  48.63  25.21  -240.0  1499.5

17:47  49.12  25.21  -240.0  1499.5

18:00  38.75  34.29  -240.0  0.0

18:01  32.01  34.29  -240.0  0.0

18:02  28.89  34.29  -240.0  0.0

18:15  51.36  26.01  -240.0  1499.6

18:16  38.85  26.01  -240.0  0.0

18:17  40.74  26.01  -240.0  0.0

18:30  43.06  24.96  -240.0  1499.5

18:31  29.24  24.96  -240.0  0.0

18:32  29.61  24.96  -240.0  0.0

18:45  36.98  26.26  -240.0  0.0

18:46  34.87  26.26  -240.0  0.0

18:47  36.14  26.26  -240.0  0.0

19:00  50.09  26.57  -240.0  1499.7

19:01  42.04  26.57  -240.0  1518.0

19:02  28.58  26.57  -240.0  0.0

 

 

 

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From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Andy Talbot
Sent: 17 March 2009 19:48
To: rsgb_lf_group@blacksheep.org
Subject: LF: Who's playing on 503.7

 

OK, Who is it?

We can see you

There's activity in the 5 and 6 minutes slots.

 

 

Andy  G4JNT
www.g4jnt.com