[hpsdr] CW operation

[Luke Steele]

Happy New Year all,
I have a question on CW ops.
My system is as follows:

Mercury; v2.7
Penelope; v1.2
Magister; v1.7

PowerSDR v 1.19.3.1 baseSVN3444

CPU; i5-760
4 GB RAM

OS; Windows 7 Ultimate 64 bit

Also running Ham Radio Deluxe and DM780
Virtual Serial Ports for interface HRD-PSDR
Virtual Audio Cables for interface DM780-PSDR

Right, all that out of the way, my question is; how do CW ops deal with the
latency of the sidetone?
The latency I am experiencing is certainly not in the order of several
hundred milliseconds mentioned in an earlier post on this forum, but is
probably in the order of low tens of milliseconds and just enough to be
annoying. It makes the paddle feel 'dead' in that if lags just enough to
cause me problems with synchronisation. I like to operate around 23 WPM by
the calibration on the slider in the CW dialog.
I understand that the sidetone is generated by simply decoding the transmit
signal in the receiver card, therefore, the latency would be that of the
exciter card processing plus that of the receiver. This is rather clever,
in that one can therefore monitor one's actual transmission, but the
latency introduced causes me problems. Are there some settings I should
look at to reduce latency to an acceptable level? I have fiddled with the
CW DSP settings, and found it a trade off between latency and filter
performance. Is there a workaround in software?
Or should I just build a sidetone oscillator and inject it at the headphone
like it has been done traditionally?

The CW transmit is the only aspect that I feel needs improvement. The
receive filters and functions are fantastic, and it operates in superlative
manner in phone. The receiver is first class, and hears as well as or
better than anything else I have here. Digital ops using the VAC interface
works very smoothly, and seamlessly.
Oh, here's a tip for those using Windows 7 with the RealtekHD audio stuff:
check in the "Sound Effects" tab, "Environment" is set to "None" or your
digi transmission will be altered by the various environment sound effect
schemes available, and it will be unreadable.

Vy 73,
Luke VK3HJ

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