QRQ CW(120wpm) over PCMA G.711 CODEC using Ekiga

[Chuck aa0hw]

The ability of the A-law PCMA G.711 audio codec to transmit extreme qrq cw audio tones over the internet, is tested using the SIP VOIP CLIENT Ekiga. https://ekiga.im/

FLdigi sends a text at 120 wpm from TOM's famous qrq cw article:
https://sites.google.com/site/tomw4bqf/copyingcwover70wpm
to the input of Ekiga, and Ekiga is connected to an ECHO REFLECTOR so you can hear your audio bounce back from the server and test your own signal. sip:*[e-mail]
http://wiki.ekiga.org/index.php/Fun_Numbers

an audio bandpass VST PLUGIN is utilized to filter out the harmonics. https://www.meldaproduction.com/MBandPass

An FLdigi tone of 2000 hertz was used since it is in the middle section of the typical voice frequency range of these types of audio codecs. The tone is pitch adjusted back to around 800 hertz by another free VST PLUGIN called the MFreqShifter.
https://www.meldaproduction.com/MFreqShifter

Ekiga, SIP, and the VST AUDIO plugins are all free software. Personal SIP addresses are free to register and acquire.

TEST RESULTS:
FLdigi transmitted the whole text of TOM's article at 120 wpm without one glitch being returned for receive, using this PCMA G.711 A-law codec over SIP voip. The cw timing was very steady and precise and represented / duplicated very well, the original transmission from FLdigi.

NOTE: the ability of an audio codec to create good qrq cw notes, with good audio quality, is much different than the codec's ability to preserve good VOICE quality during its compression/coding and transmission and the reconstruction on the receive side...

also ...a codec's ability to handle packet delay/ loss, using packet loss concealment etc, all help in general for good cw copy.

The bandwidth my UPLOAD and DOWNLOAD internet graphs showed , were only about 80k each way.