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Typical UberSDR problems people encounter.

Started by Bas ON5HB, Jul 25, 2026, 03:48 PM

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Bas ON5HB

The biggest problem is probably CPU overloaded.

To overcome this install cpufrequtils, yes this one, not the new cpupower.
Then alter the speedlimits to e.g. something like this in /etc/init.d/cpufrequtils:

ENABLE="true"
GOVERNOR="powersave"
MAX_SPEED="3G"
MIN_SPEED="2G"

My CPU can do 3.4GHz but I do not want it to go there, but the bottom is 800MHz and that is a major problem, as things go wrong and it's not fast enough back on speed. Sure you can set ondemand or performance, but then it will run max speed all the time.
You can do that, but the CPU may get too hot causing other issues. Intel's do not like to be run at max all the time. As such I maximized the topspeed. 2GHz is sort of the bottom you need to run well.

Other problem is decoders, like WSPR and FT8, set them to 1 concurrent decoder, it's set to 2 but unless you have 8 or more REAL cores, set it to 1.

Don't let it decode too deep, as it will take too much CPU and too much time to decode.
For WSPR as good decode is FAST 2500, but if you need CPU-cycles, just set it to 1000 ULTRA FAST, it will still decode a lot of stations.

Best to start with FAST-decodes for all modes. Beware, you need a very fast and >10 core CPU to decode ALL modes. Don't decode everything.

Use the session-tester to determine max users, a typical is 50-100 users, unless you have a very modern >10core CPU.

I hope this helps to get most problems sorted when you start.



Best regards,

Bas ON5HB

Ps. Running UberSDR.

Emmanuel SV1BTL

🖥� CPU

12th Gen Intel(R) Core(TM) i5-12600H (16 cores)
51 °C  (driver: coretemp)

with GOVERNOR="powersave"

With all the decoders on, I am getting +20 degrees up.

----

The AGC performance has improved significantly in the latest version of UberSDR. Both the user-configurable manual AGC parameters and the fixed sysop-defined configuration are now working correctly. However, I believe the AGC implementation could still benefit from further refinement, particularly in terms of response behavior and handling of weak signals.

The automatic waterfall-level adjustment has also improved considerably in the newer release and now produces more consistent results.

Latency remains one of UberSDR's strongest features compared with other WebSDR platforms. PhantomSDR's current latency is very close to that of UberSDR and, in my tests, effectively identical to the P.T. WebSDR implementation.

PhantomSDR can now decode FT4, FT8, and WSPR signals and automatically upload reception reports to PSK Reporter and WSPRnet, as UberSDR does. With all digital-mode decoders enabled simultaneously across all available bands, the CPU temperature increases by approximately 20°C. However, CPU utilisation remains within acceptable limits and there is no indication of processor saturation. The system can also support approximately 25 concurrent RADE listeners without significant CPU overload, thermal instability, or noticeable degradation in receiver performance.

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