has anyone else suddenly started having trouble copying HF fax?

[Jim_Shaffer]

Last time I tried was about two weeks ago, and everything worked fine. Last night I started having problems with losing sync frequently. It seemed to happen most often when moving or closing windows, or scrolling web pages, but NOT exclusively -- I left it running overnight with no other activity on the computer and it still happened multiple times on every image, just not as much as when I was active on the computer. I've changed nothing other than switching from a 1080p monitor to a 1440p monitor -- but I have a Core i5-3570K CPU and Nvidia GTX 960 GPU, so the additional resolution should hardly be taxing the system.

The only other thing that's changed was the usual weekly Windows updates. I did see some comments online to the effect that a recent update has been causing sound problems for some people, but I don't see any details other than "sound doesn't work", and mine works. (I did have to re-assign my virtual cable inputs and outputs in my SDR program and my decoding program though, because the update renumbered all the sound devices for some reason -- but it's done that before with no catastrophic effects.)

At this point I've tried two different SDR programs and two different decoding programs, and re-installed my virtual audio cables with the latest version.

 

[KE5MC]

You might want to look closely at the VAC setup/configuration. At one time I had problems with mine after not using it after several months. It turns out the sampling rate had moved to a mid-range value. I bumped it up to the top and all was well. Depending on your VAC other parameters might be in play like buffer size.
Mike

 

[Jim_Shaffer]

Well, I thought I might have solved the problem. I was poking around in the Windows device configuration panel, and I noticed that my GPU and the USB port that my SDR is on were using the same IRQ. So I moved the SDR to a USB port that was on another controller, and for a while everything ran perfectly. But then I started getting small jumps in the decoded images again. Not nearly as frequently or as large as before, but still about one every other decode, even if I'm not doing anything else with the computer.

 

[Jim_Shaffer]

You might want to look closely at the VAC setup/configuration. At one time I had problems with mine after not using it after several months. It turns out the sampling rate had moved to a mid-range value. I bumped it up to the top and all was well. Depending on your VAC other parameters might be in play like buffer size.

I'm not sure I have a buffer size adjustment. I'm using the free VB-Audio Cables system, not the paid version.

Concerning the sample rate, what should I be setting it to? Most decoding programs default to either 11025 or 44100. Should I set everything to the same? I would've thought that my CPU would be fast enough to resample without errors, but maybe not...

 

[Jim_Shaffer]

I might finally have things settled down. I set the sample rate to 48000, but cut the resolution down to 16 bits instead of 24 bits. Also, I noticed that Cortana had access to my audio input. I thought I turned that off long ago, maybe it got turned back on by a Windows update. So I turned it off, along with a lot of other apps that were listed as having listening permission, including some that I can't even imagine what they'd be doing with audio. (Microsoft Photo?!) I had one glitch shortly after that, but everything's been perfect since then. Hopefully it stays that way!

 

[bobruzzo]

I have been copying WEFAX from station "NMF" out of Boston Mass since last year. It took a while for me to adjust radio and FLDIGI, so I was able to receive some nice charts and satellite pictures. I use my IC 7300 on the frequency 6.338.6 and a G5RV as inverted V. I live in Rhode Island so I am not real far from the station. I notice sometimes even with a real strong 20+ signal, sometimes I get lousy copy. I am wondering if that station has a directional antenna because these wefax transmissions are primarily for ships at sea. I would probably be in a null at times, mixed in with propagation differences. Attached is a satellite image I copied yesterday of Hurricane Ian which you can see is on west coast of Florida. The other chart is north Atlantic iceberg report. So it's hit or miss, and I think its propagation. I wrote to a few contacts and the Coast Guard asking for information about station NMF but I never got reponse. NMF transmits on about 4 different freqs but I primarily always hear them on 6.338.6....signals sometimes come booming in, and other times signals are erratic. I dont get it. I am not sure if NMF is located on Cape Cod or near Boston. There is no online information that I could find. I am hoping later in the Fall signals will improve.

 

[dlwtrunked]

41°42'45"N 70°30'9"W
Your Rhode Island location is not "close"--you are too far for good ground-wave except on lower HF frequencies and too close for traditional HF ionospheric reflection. This is from experience of having lived about 8 miles from an HF transmitting facility that on higher HF frequencies was always weak hear and would pick up strength hundreds of miles away and be booming in at 700 miles from the transmitter site.

United States Coast Guard Communication Station, Boston (NMF) - Wikimapia

USCG COMMSTA Boston 4700 Greenway Road Forestdale, MA 02644 (508) 888-4556 http://www.uscg.mil/lantarea/commstaBoston/

wikimapia.org

Marine Weather Broadcasts from the USCG

 

[bobruzzo]

41°42'45"N 70°30'9"W
Your Rhode Island location is not "close"--you are too far for good ground-wave except on lower HF frequencies and too close for traditional HF ionospheric reflection. This is from experience of having lived about 8 miles from an HF transmitting facility that on higher HF frequencies was always weak hear and would pick up strength hundreds of miles away and be booming in at 700 miles from the transmitter site.

United States Coast Guard Communication Station, Boston (NMF) - Wikimapia

USCG COMMSTA Boston 4700 Greenway Road Forestdale, MA 02644 (508) 888-4556 http://www.uscg.mil/lantarea/commstaBoston/

wikimapia.org

Marine Weather Broadcasts from the USCG

OK thanks, I have been looking for information on that station for a while. There is a 4Mhz freq they also used to use and I would get a bit better reception. I have heard the New Orleans, La site from time to time but weak. I guess its luck of the draw for me. Thanks for filling me in on the details.