I would be VERY curious how the numbers come out if you set the sample rate to 12000 instead of 11025. Not sure it will be better, worse or any any more accurate.
As far as accuracy of calibration goes. I would trust WWV. I understand that the sound checker program is based on an internal PC clock which only has an accuracy of +/- 100 ppm. I think that Olivia's requirements are fairly tight but SSTV even tighter. If you give 12000 a try, please let me (us) know the results. By the way, I use the MixW SSTV method against WWV for calibration on receive. I usually set transmit to the same value assuming it is using the same clocks. Not sure of this assumption. Regards & 73, Kevin - K4VD On 1/8/06, Ron Walters <[EMAIL PROTECTED]> wrote: > Yes, you guest it, right during the RTTY test I lost audio in, thought I > had a bad cable or lose connection, but no, the dam sound card > (Soundblaster 16bit) just stopped working. So in the mean time I > decided to drop back and use the on board sound card. I then check the > calibration against WWV tick using both MMTTY and MMvari and MixW SSTV > calibration method. > > All three showed a +40 PPM at 11025hz. No problem, but I also wanted to > make sure that the transmit (Audio out) was also calibrated and > downloaded the sound card calibration program off Yahoo and ran it at > the 11025 sample rate. > > After a long time that program started to zero in on the "in and out" > corrections, they were +15ppm on the in and -79ppm on the output. > > Using the 40 ppm corrections for two SSTV programs (MixW) and MMSSTV, I > transmitted on one and received on the other and got a considerable > slant, tried it both ways same slant conditions., I then inserted the > -79 ppm in the transmitting and the slant almost disappeared but was > still there, then I adjust the receive in to +20 PPM and the slant > almost disappeared. > > Question: Show I rely on the WWV tick correction +40ppm for most other > programs? or the +15ppm that the soundcard checker program returned > based on the PC's internal clock or some compromised value? > > Should I rely on the OUT correction of -79ppm which up until this > incident I had not set. When running both SSTV programs that were > consistent with a good display based on the checker program, when using > the WWV values I had a slant on the receiving pics. > > I operate Olivia, Contestia, MFSK and some PSK RTTY. I do not think > that the PSK, RTTY adjustments are as critical but I am concerned how > well Olivia and Contestia and Hell will work. > > Am I being overly concerned with such small (Less than 1HZ) adjustments? > > Probably by the time some of you read this I will have slipped in > another SB soundcard and started the calibration process. all over > again, your thought are appreciated. > > Ron W4LDE > > > > > Need a Digital mode QSO? Connect to telnet://208.15.25.196/ > > Other areas of interest: > > The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ > DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) > > > Yahoo! Groups Links > > > > > > > Need a Digital mode QSO? Connect to telnet://208.15.25.196/ Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
