Locked FT8 -- not decoding after transmit. Decodes fine for Receive Only
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Hello all,
I could use assistance with WSJT-X decoding. I spent quite a bit of time examining this problem and capturing data in what I hope is an understandable format. You might be tempted to respond quickly after reading only the problem statement. Please take a moment to glance over all the data; I've tried several remidies from previous threads in this forum. Help is appreciated.
Regards, Curt / K7ZOO
PROBLEM STATEMENT After I transmit, no decodes are displayed. The waterfall pauses for a few seconds after transmitting. Process "explorer.exe" and one or more "svchost.exe" processes use the CPU after transmitting (during the receive cycle), during 50% duty cycle tests. During receive-only tests, these processes ("explorer.exe" and "svchost.exe") do not appear to be active at all.
KEY ITEM: I'm not sure why "explorer.exe" and "svchost.exe" appear very active after transmitting. They don't appear to be necessary to decoding, as they are not active when I'm only receiving. Please see below where I've set the priorities of some processing, in an attempt to allocate more CPU to WSJT-X. My intuition is that something in my system causes these processes to run, and they don't need to run at all for WSJTX decoding.
COMPUTER MAKE / MODEL HP Elitebook Folio 9470m PROCESSOR Intel Core i5-3427U 1.9 GHz 2.4 GHz RAM 8 GB (7.87 usable) WSJT-X
Version 2.1.2 0068f9 (installed 2-27-20)
TRANSCEIVER MAKE / MODEL Icom IC-7200 FREQUENCY 14.074 MODE USB AUDIO FILTERING 3600 Hz wide DATA ON RF POWER tried both L and 30 watts; same behavior MoD U D-MoD U USL LVL 50
PRIORITIZATION OF PROCESSES I downloaded, installed, and used “Process Hacker 2” to examine and set the priority of CPU processes as shown below: wsjtx.exe Priority Real Time I/O Priority High Save for wsjtx.exe checked Jt9.exe Priority Above Normal I/O Priority Normal Save for jt9.exe checked explorer.exe Priority Below Normal I/O Priority Very Low Save for jt9.exe checked
OBSERVATIONS a) WSJT-X does decode normally when I’m only listening b) After transmitting only once WSJT-x skips (does not) decode for 1 to 3 cycles. The DECODE button does not turn blue when it skips (does not) decode. Decoding resumes after 1 to 3 cycles. c) While transmitting at 50% duty cycle, WSJT-X does not decode. c) Signals are always present / visible on the waterfall.
Graphs of CPU usage are shown below for (a) RX only, and (b) RX and TX at 50% duty cycle
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Curt, I'm no expert but I did cue on your priority settings. I experimented with them at one time with WSJT-X, with mixed results, but some research showed interesting information.
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Setting Priority to High was classed as being a bit dangerous as it assigns too much time to a subject,. Setting a Priority to High was asking for trouble, as doing so could conceivably cause that app to, in effect, lock into a loop, excluding any other tasks meant for it. I Can't recall the study this info came from or I'd credit it. I use a minimum system - an AMD 2-core CPU at 3.0 GHz and only 4G RAM. I've never had a need to set a priority to higher than "Above Normal". I stopped adjusting priorities quite some time ago as not being necessary. I also discovered that when I use AGC, it frequently is slow bringing a received signal back to a level needed for decode, especially on a busy band, or where CW is present within the band-spread. Not sure this will help at all. Maybe just the ramblings of a tired man, 73 es GL Dave - KB3MOW On 2/27/2020 4:28 PM, Curt L wrote:
Hello all, |
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Curt K7ZOO
Hi Dave, Thank you for the insights on setting the priorities for the CPU. I'll examine the AGC as well. Currently on the IC-7200 I have the AGC set to fast -- I will disable it and see if that helps at all. The most striking corrlelation I see, though, is with the process "explorer.exe" using more CPU cycles after a transmit event.
Regards, Curt / K7ZOO |
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Al Groff
Curt,
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I have observed that FT8 does not decode if the total CPU usage is high at the start of a receive cycle. In my case I had a logging program that had high cpu usage at the end of a RX cycle overlapping into the next cycle and killing the folowing RX cycle. I am unable to explain why your system has high CPU usage at the end of a transmit cycle. I would suggest stopping as many non-WSJT programs as you can and see what happens. AL, K0VM On 2/27/2020 3:28 PM, Curt L wrote:
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Curt K7ZOO
Hi Al, Thank you for the response and advice. The high CPU usage occurs right at the beginning of the receive cycle, following a transmit cycle. You and I have experienced exactly the same problem, except I don't know the root cause of the high CPU usage at the beginning of the receive cycle. I am not purposely running any other software other than WSJT-X. I will keep digging for the root cause. Thank you! Regards, Curt |
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Al Groff
Curt,
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One further thought... Try transmitting with the PWR set to zero ( radio keyed but no rf out) and see if the high CPU load is still present.. Then I am out of ideas.. AL, K0VM On 2/28/2020 11:35 AM, Curt L wrote:
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Curt K7ZOO
Hi Al, Thanks for another good idea. I did transmit with zero power, and 50 watts, and the problem persists. Regards, Curt |
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John KI4WCQ
Curt,
A friend of mine has a similar problem when in Hound mode. Decode and monitor stops after his transmissions. I have seen his screen shots and he will have no decodes for several minutes. If he goes out of Hound mode everything works fine. We haven't been able to figure it out. His settings are the same as mine except for the type rig...his is a K3. 73 Johnny KI4WCQ |
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