Periodic iChat audio dropouts over Airport on Intel iMac

Question

When chatting with iChat, an audio dropout occurs exactly every 5 minutes on my new Intel iMac. iChat's Connection Doctor shows total loss of receive audio signal quality (and a halving of the receive bit rate) for about 5-10 seconds. Then normal operation resumes for 5 minutes and the problem repeats. This only occurs while using iChat over Airport. I can also force this audio dropout behavior at any time by clicking on the Airport status icon on the menubar. I wonder if others are having this problem or is this an isolated problem with my computer?
It took me a while to recognize that this wasn't a network problem causing occasional audio dropouts. My wireless D-Link router isn't the culprit as my G4 iMac and G3 laptop don't exhibit the problem through the router. Also, when connecting from the Intel iMac to any of the other nearby Macs using a computer to computer Bonjour wireless connection (thus eliminating the router) the dropouts do occur. After connecting, the dropout always occurs at a random time between 0 and 5 minutes but thereafter it occurs at exactly 5 minute intervals. If I click on the Airport status icon to force the audio dropout, the next dropout will occur 5 minutes later.
I also have a new Intel Mac Mini which doesn't exhibit the periodic audio dropout problem but does have a similar audio dropout whenever I click on the Airport status icon. The dropout lasts longer on the Mini - about 15 seconds average before the audio signal quality fully recovers. Because the periodic dropout doesn't happen on the Mini, it isn't really an operational problem, but it is instructive to note that only the Intel Macs exhibit this particular behavior.
In troubleshooting the iMac, I have turned off all timing related items that I can think of including, Mail (check manually), Set Date and Time Automatically (OFF), all sleep, hard drive and screen timers OFF, all iCal reminders OFF, etc. I have also turned all Dashboard Widgets OFF, corrected permissions, tried a different user ID, reset the NVRAM and SMC. I have even tried setting the iChat app to open as a Rosetta app . Nothing has solved this problem yet.
The iMac is a dual core 20" with 1.5 GB of RAM and the Mini is a dual core with 512 MB of RAM. Both are running Tiger 10.4.5 Wireless signal level in all tests is 100 percent.
Thanks for any help.
Bill

Answer 1

OK, I have my Intel iMac connected to the Internet via an Ethernet converter. What this means is that the iMac is connected via Ethernet cable to the Ethernet converter, which, in turn, communicates wirelessly with a wireless router.
This seems to clearly solve the wireless connection audio issue as the Intel iMac thinks it has only an Ethernet connection. There is no audio dropout after five minutes or so, but there may be other Mac to Mac connection issues related to Intel Macs.
I'm going to run with this connection for awhile to see if there are other problems, but this seems to be a good workaround for the moment. I'm using a Buffalo Technology WLI-TX4-G54HP Ethernet converter, which costs about $60 USD at most online vendors in the US.
Although $60 may seem like a lot of money to spend on an Apple-created problem, using the Buffalo high power device is almost surely going to provide significantly better wireless range. This increased range advantage may be enough to offset a large part or all of the $60 cost.