I have had strange audio problems on the URI when the usb port is acting up or failing. I changed ports and it went away. -----Original Message----- From: app_rpt-users-bounces@qrvc.com [mailto:app_rpt-users-bounces@qrvc.com] On Behalf Of Shawn Hastwell Sent: Tuesday, August 17, 2010 10:58 PM To: app_rpt-users@qrvc.com Subject: Re: [App_rpt-users] Strange oscillation On Tue, Aug 17, 2010 at 10:42 PM, Stephen Rodgers <sales@qrvc.com> wrote:
kb8ude@gmail.com wrote:
I am still testing my hardware here on a dummy load and having strange behavior. First, my hardware:
Dell P3 1.13GHz server, 1gb RAM, 36gb SCSI drive, installed via ACID CD. URI interface, output cable about 6 inches long, twisted but not shielded. Motorola Radius M120 UHF turned down to 20W. Set as a simplex link and the channel is set to carrier squelch.
Set my audio levels using a Motorola service monitor.
Sometimes when the radio transmits I get clear voice. Most of the time there is a noticeable low frequency oscillation on the signal and the audio is unreadable. Almost sounds like mid-rpm engine ignition noise if that helps paint a cleare picture of the sound. RX seems good, I am listening using iaxrpt on the pc and can hear myself slightly delayed and clear.
I tried a couple ferrites on both sides of the URI with no change. I also noticed that sometimes the 'connected' announcement has a ripping or tearing sound to it as well as stuttered courtesy tones on occasion. I am wondering if my server just isn't fast enough or if the URI needs a 2.0 USB port to plug into.
Any thoughts folks?
-Shawn
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Slow PC: If you run the 'top' command from the linux shell command line, how much CPU is being consumed by asterisk? More than 25% is asking for trouble. Try a faster pc and see if it clears up the problem.
Audio oscillations: It's hard to say what might be wrong. This could be CPU speed related, interface adjustment related, or a grounding/ground loop issue. It wouldn't hurt to look at the URI audio output with the scope in your service monitor while it is oscillating.
BTW: Ferrites are no good at reducing noise at audio frequencies.
Steve WA6ZFT
I am still getting used to the service monitor and how to do various things with it properly. I will see what I can do in that regard. TXVoice and TXTone are at 300 and 175 respectively. I did a 'top' while there was audio activity connecting and disconnecting from the Echotest server. It peaked near 22.3 and only one time at 24.8. I was thinking RF may have been affecting the URI, hence the ferrites. I am not ruling out the radio as the cause directly though, I understand that some of these models will exhibit some erratic behavior when turned down too far based on the rated average power. I am going to turn it back up to it's rated power and see what happens as well. -Shawn _______________________________________________ App_rpt-users mailing list App_rpt-users@qrvc.com http://qrvc.com/mailman/listinfo/app_rpt-users