[Skimmertalk] CW skimmer audio output stutters under load

bubnikv . bubnikv at gmail.com
Sun Aug 16 15:29:08 EDT 2015


>
> I'm confused.  Which sound card are you using, the external one or the
> internal one?
>

I am using an external sound card as the internal sound card has mono input
only.

I should note that CW Skimmer has never produced super clean audio output
> for me, especially when the CPU is busy.  MME output always sounds better
> than WDM.  But there are always ticks and pops no matter what you do.
>

I believe VE3NEA developed CW skimmer on a top notch desktop computer with
good drivers and low latency, so he is not aware of the difficulties one
faces with a less then stellar hardware and the device drivers.

On that 2007 laptop, if I set the maximum number of decoders to 50, I
elevate the process priority using the Task Manager to High and the CW
skimmer is the only application loading the computer significantly, then I
get no drop outs and the CW skimmer is usable as a receiver. That is, after
I disabled the WiFi driver, which was introducing regular latency spikes.
With 50 decoders, the two core machine has one core loaded to 50% (CW
Skimmer is single threaded only, it will not load the other core). If the
bands are busy and I leave the CW skimmer to adjust the number of decoders
adaptively, I will soon get audio drop outs.


> Note that CW Skimmer was designed for automated spotting, not for hi-fi
> listening.  I suggest muting the skimmer audio output using the button on
> the CW Skimmer toolbar, then and use a real receiver controlled by
> BandMaster, N1MM+, Win-Test, etc. to listen to signals.  Use CW Skimmer to
> feed spots to these programs via the built-in telnet server, and click on
> spots in the band map to move your real receiver to the spot frequency.
>

Thanks for an advice, that will certainly work. But the SoftRock is
currently the best receiver I have in my HAM shack. I am an avid
homebrewer. I plan to write a piece of software to control a DDS
transmitter synchronously with the SoftRock and the CW skimmer.

I find the CW skimmer and the Rocky program superb for bed side listening,
commanding the PC remotely using my Android phone. Both CW skimmer and
Rocky have a function to jump between detected CW signals with up / down
keys. This makes the tuning from the Android phone very comfortable.

It seems to me though that the CW skimmer audio filter is sharper and rings
significantly more than the filter of the Rocky SW.

73, Vojtech OK1IAK


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