Author Topic: K3 using DUAL RX with any Audio Quality other than 0 has choppy audio  (Read 511 times)

K7ZS

  • Newbie
  • *
  • Posts: 13
    • View Profile
    • Email
HNY All!

The subject line says it all.  We have been using Audio Quality 0, ALAW 8Khz but have been pretty disappointed with how it handles dropouts, compared to AQ setting #f 2, the LINEAR 16 Bit 8 Khz.  All users and the station now have greatly improved internet connections, so we decided to improve audio quality and move to a different setting.

THE PROBLEM is while it works great WITHOUT the DUAL-RX on, as soon as we switch to having both receiver audio streams available in the headphones, the receive audio quality suffers, regardless of the Jitter Buffers and Jitter Delay settings.  It introduces a 'crackling' component to the audio that is really noticable on CW, and especially when tuned to a fairly strong signal.

This is a competition station, so we don't want lots of T/R delay which is introduced with the increase in the jitter settings.  All other settings have been tried and perfected over 2 full contest seasons of use.  It's a full M/2 station, and we are experienceing the trouble on BOTH stations, so we have ruled out a single radio or remote rig hardware item as the source of the problem.

We have tried virtually everything, and cannot seem to find a setting that works, OTHER than going back to ALAW 8Khz...

The radios are fully loaded and updated K3's, K3/0 for the control side, late build RR boxes, latest firmware, very good and dedicated internet connection at the station (nobody firing up Face Time or NetFlix etc.)

Any clues to share would be greatly appreciated.

73 Kevin K7ZS

sm2o

  • Administrator
  • Hero Member
  • *****
  • Posts: 2485
    • View Profile
    • sm2oan
    • Email
Hi
The problem is that you have to low bandwidth available for the audio stream. Dual RX needs double bandwidth.
There is no difference in how the RRC handle dropouts etc depending on codec, it's just the payload which is different

73 de mike

K7ZS

  • Newbie
  • *
  • Posts: 13
    • View Profile
    • Email
Hi Mike, thanks for the q

We have arranged for a SYMMETRIC service at the radio site, MINIMUM 5 Mbps both up and down. Often in excess of 10Mbs.  The bandwidth while in operation (monitored at remote site with DD-WRT's bandwidth monitor tool ) is only about 350Kbps ... Nobody is at the remote site to increase total traffic.   The trials were done with a client that has over 100 Mbps download speed, which is becoming the norm here in USA.  He has a sub 50ms ping rate to the site, being only 80 miles away.

So, respectfully, I doubt it is a bandwidth issue.

Any other ideas?

Thanks ... Kevin K7ZS


K7ZS

  • Newbie
  • *
  • Posts: 13
    • View Profile
    • Email
ADDED NOTE:

The audio is not as much CHOPPY as in complete dropouts, but described as a CRACKLE on the audio.

Kevin K7ZS

sm2o

  • Administrator
  • Hero Member
  • *****
  • Posts: 2485
    • View Profile
    • sm2oan
    • Email
Hi

there is no other reason. If reducing bandwidth demand give less dropouts it's obvious. Me and many with me using quality 2 for K3 twin daily. With > 1 Mbit stable internet connection it's no problem.

73 de mike