locked Re: Seeing a Lot of Skipping Decodes Every Other Sequence FT8

JTAlert Support (VK3AMA)

On 17/03/2020 9:26 am, Hasan Schiers N0AN wrote:
On a busy FT8 Band like 20m, I'm seeing more and more tendencies to skip an entire sequence following a decoded sequence.

I'm on 20m FT8 now and it is happening nearly every other sequence, or it will decode 2 seq in a row and then start skipping again, without any intervention on my part.

Then it will start decoding again, do several sequences in a row (with me not transmitting, just monitoring), and then skip another sequence. I just watched it do it again while typing.

I have stopped interacting with the program, I am just letting it run with no intervention, receiving:

Two more in a row of > 20 stations
Then skipped an entire sequence
Full seq of decodes > 20
Skipped the next sequence
Full seq of decodes > 20 stations
Skipped the next seq
Full seq of decodes > 20 stations
Skipped the next seq: no decodes
Full seq of decodes > 20 stations
Skipped the next seq: no decodes
Full seq of decodes > 20 stations
Skipped the next seq.

The computer running the X software is not being touched. I'm typing on a different machine.

WSJT-X 2.12, Win10 Pro, Core I5 3.2 GHz,  8 gB of RAM (Win10 Pro is fully up to date)

While receiving CPU is about 6 %
While decoding at end of seq: 30-50%
When it skips a cycle, CPU does not go nearly as high, perhaps 25% max

UDP > JTAlert
JTAlert Rebroadcast UDP > DXLab SpotCollector

I have WSTX folder excluded from virus check
I have the WSJTX appdata folder excluded.

I just stopped JTAlert and am now having WSJT-X talk UDP directly to SpotCollector.

Every sequence is decoding > 20 stations, No Skips
CPU Utilization is 30 to 50 % as before at the decode
It's been about 20 minutes with absolutely perfect decoding of > 20 stations every sequence. I only made one change.

Last decode seq, the CPU went as high as 66% ...still got perfect decodes.

I have no explanation or theories to offer, but if I want consistent decodes I can't run JTAlert ...and I love JTAlert, but I'm tired of fighting this.



The only direct interaction JTAlert has with WSJT-X is when it either sends an instruction that a Callsign has been clicked or when painting the decodes with Alert coloring, both of which occur AFTER WSJT-X has produced its decodes. Unless decodes are excessively delayed such that JTAlert is sending coloring instructions to WSJT-X long after a new period has started, there is nothing that JTAlert is doing that would interfere with WSJT-X decoding. try turning the Decodes coloring off in JTAlert.

If your not happy with JTAlert and believe it is the true cause of random WSJT-X decode failings, the answer is simple, don't use it!

de Laurie VK3AMA

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