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Pure signal or auto ATT issue. 300Khz wide splatter

Posted: Fri Nov 24, 2023 4:03 pm
by ea3aqr
I've found an issue with pure signal, very visible, when using 2TONE.

If you adjust pure signal at a very low drive level and then you try to adjust for a full power output, PS produces a very wide 300Khz splatter/spike while auto ATT is trying to find the correct value.

Same issue, but not as clearly visible, when PS auto adjusts using your modulation.

Tested in my Anan 7000DLE/Thetis 2.10.3.4 and also in an Anan 7000MK2/Thetis 2.10.2.2 from a friend of mine.

First time I saw this issue was 15 days ago when going from low to high drive power on 15m. After the spike/splatter, one of the LDMOS transistors in my power amplifier was damaged because of a fast SWR trip.



Is anyone else experiencing the same issue?

Re: Pure signal or auto ATT issue. 300Khz wide splatter

Posted: Fri Nov 24, 2023 5:23 pm
by DH1KLM
If you suspect a problem, post it to Github.

https://github.com/ramdor/Thetis/issues/new/choose

Re: Pure signal or auto ATT issue. 300Khz wide splatter

Posted: Fri Nov 24, 2023 6:15 pm
by ea3aqr
DH1KLM wrote:If you suspect a problem, post it to Github.

https://github.com/ramdor/Thetis/issues/new/choose



I was asking people before posting to GitHub to confirm if it is a wide spread issue.

Re: Pure signal or auto ATT issue. 300Khz wide splatter

Posted: Fri Nov 24, 2023 6:50 pm
by w-u-2-o
That is completely normal behavior. That is how PS has always worked. As @mw0lge wrote, it takes a finite amount of time for PS to analyze, adjust and implement a correction.

However, it does beg the question of whether anything could be done to make the process more graceful. But in the meantime, again know that this is "normal".

Re: Pure signal or auto ATT issue. 300Khz wide splatter

Posted: Fri Nov 24, 2023 7:03 pm
by ea3aqr
I understand that PS takes some time to adjust.

It could be me, but I don't remember to see that 300Khz wide splatter when PS was analyzing/adjusting.

Thanks anyway!