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Shortwave Data Decoding - Discussions regarding decoding digital signals on the HF bands, including HFDL, ALE, RTTY, CW, and others.

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  #21 (permalink)  
Old 09-20-2017, 5:44 PM
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Small update...

We confirmed it was not from the NWS location this afternoon but troubleshooting continues as there are a bunch of jumps between us and USCG and then to the broadcast. Just want you folks to know we aren't letting this sit
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Old 09-22-2017, 7:18 PM
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This issue has been discussed over on the UDXF group, and it's the general consensus that it's a fault on the USCG end. In fact Chris Smolinski of Black Cat Systems has been in touch with the USCG, and has been told that they are aware of the issue and it's being addressed.

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  #23 (permalink)  
Old 10-17-2017, 9:43 AM
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Default voip

I am suspecting they are sending the tones to the transmitters over a voip link somewhere, either their own or
most likely a commercial provider. The delays in the sync look a lot like problems I have seen in other attempts to send time critical signals over voip. The problem is when the route changes as it will do over a tcpip path as that is how tcpip works. The latency changes somewhat for different routes giving rise to data sync problems. A better solution would be to send the entire pic file to the remote site and do the encoding there.
Just a thought.

Eric WA3UYI
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Old 10-17-2017, 9:55 AM
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Quote:
Originally Posted by jhildreth View Post
One other thing...can you tell me when this issue started? We are trying to figure that out to see if either USCG or us did something at the time this started which may have caused the problem.
I am the OP. I noticed the problem in the spring of this year. At first I thought it was computer problem at my end. As of this date the problem still occurs with some of the pics ok, others with jumps. See my posting about possible use of voip causing problem. Just a guess. The pix later in the evening seem better than the ones during the day. Which would make sense if voip is being used as route changes are more common and frequent during busy times of day.
This is a total guess on my part as I have no idea of the path flow from wefax encoder to transmitter.
Eric WA3UYI
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Old 10-19-2017, 5:32 AM
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I've been told that fldigi 4.0.11 helped one user clean up some issues he was having.

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Old 10-19-2017, 8:33 AM
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I use Fldigi, that version. It attempts to resync when phasing jumps, but still pix not good. As the problem is not with the decoding end not much will help. The dedicated fax receivers on board ships and boats also have the problem. This is a serious situation, not just for hobbyists. I notice the problem seems a bit better lately. Yesterday only 6 out of 15 pix showed phase jumps. It's funny, I have been rx wefax for 20 years or so and never had a problem with any of the pix, only poor rx conditions from time to time, noisy and such, until this year.
Eric WA3UYI
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  #27 (permalink)  
Old 10-24-2017, 11:37 AM
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Default uscg info

apparently USCG is on the problem:



NOUS41 KWBC 121335

PNSWSH



Service Change Statement 17-109

National Weather Service Headquarters Silver Spring MD

935 AM EDT Thu Oct 12 2017



To: Subscribers:

-NOAA Weather Wire Service

-Emergency Managers Weather Information Network

-NOAAPORT

Other NWS partners and NWS employees



From: Allison Allen

Chief,Marine,Tropical and Tsunami Services Branch



Subject: Degraded HFFAX Transmissions Effective Immediately



The U.S. Coast Guard is currently experiencing degradation in

image quality of all HFFAX (WEFAX) products. The NWS and Coast

Guard representatives are troubleshooting the problem.

We apologize for the inconvenience.



HFFAX products can be obtained using the NWS' FTPMAIL system.

This is a system where a user can request and receive HFFAX

(WEFAX) products via email. If internet access is available,

go to:



National Weather Service Marine Forecasts - FAQ



to learn how to use the FTPMAIL system.



If internet access is available, HFFAX (WEFAX) products can also

be viewed online at:



Marine Radiofax charts



National Public Information Statements are online at:



NWS Public Information Statements, Service Change Notices, Technical Implementation Notices



NNNN
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  #28 (permalink)  
Old 11-06-2017, 12:30 PM
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Myself and then we’re working the issue... we have put in place a short term fix until the re-design is complete. It should have been noticed since Nov 1 that the images are MUCH clearer.

Let me know if there are any issues and we can look into them.
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  #29 (permalink)  
Old 11-06-2017, 1:00 PM
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Default hffax

I have noticed the pix are much better. I got 6 out of 6 this AM, so it is definitely better. Props for the good
work.

Eric Furness
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Old 11-06-2017, 1:07 PM
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So much better!! Nice work and many thianks to you and the NOAA/USCG team.
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