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Thursday
May192011

TWiRT 83 - Amateur Radio For Professional Engineers

UPDATE - 20-May-2011:

The magical and revolutionary editors at the TWiT Cottage have put together the usable portions of our TWiRT 83 episode.  The audio version is available for download at http://twit.tv/twirt83 or at the usual link at the bottom of this post.  Video version to follow shortly.

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Technical difficulties cut the show short on Wednesday evening.  Chris Tobin (in New York) could not get reliably connected to the TWiT studios via Skype.  My own Skype connection (from Nashville) to TWiT started out OK for a while, but then got worse and finally would not stay stable.  Chris Tarr's connection seemed reliable from his location in Mukwanago, WI (outside Milwaukee).   About 2/3 of the way through the show we had to give it, surrendering to the Devil of Variable Latency.

Checking some web sites, including www.internettrafficreport.com, we noticed quite a lot of latency and dropped packets in North America.  I don't know what a normal amount would be for a given evening, but that web site was reporting 18% dropped packet across North America and 7 major routers being completely down.

After the show, I did ping and speed tests to several sites around the USA.  I was actually getting 25 Mbps DL speed from a server in San Francisco and about 2.5 Mbps UL speed.  In my tests, I noticed getting better DL speeds than I usually see, but slightly lower UL speeds.  Employing the jitter test from www.whichvoip.com, I was seeing amazingly good results there, with under 1 ms jitter and 0 packet loss.  Obviously, that test didn't try going through any downed routers.

After those tests, Chris Tarr and I had a video Skype call which turned out to be basically perfect. Seems we, too, were avoiding any Internet bottlenecks.

It'll be interesting to see if we can know what happened and why.  Usually, when using Skype, we find that trouble is in the "last mile" - and mostly in the local home-to-ISP connection.  It's often a non-configured or poorly-configured home router at one end or both.  This time, however, seems the trouble was beyond the reach of any party to the TWiRT conversation.

My apologies for a busted show.  We were having a great time discussing how an interest and participation in Amateur Radio enhances the knowledge and career of Broadcast Engineers.  Chris Tarr gave us a tour of the Dayton Hamvention coming up this weekend.

I hope you'll join us next week as we soldier on to bring you another lively discussion of radio technology on This Week in Radio Tech.

 

OH, BTW, a couple days ago I had an audio Skype conversation with a friend who is doing work in Kabul, Afghanistan.  He was staying at what's basically a bed and breakfast.  According to the Skype stats, our Interent connection was fabulous.  Latency was a little high at about 700 ms.  However, the jitter was a rock-solid 20 ms.  Seems Kabul is well-served by some ISP.  Perhaps US Military?  Perhaps a non-gov't organization (NGO)?  Anyway, I was amazed.

My best!

Kirk

Download the fixed-up show here...

TWiRT 83 - Amateur Radio For Professional Engineers

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Reader Comments (1)

If it doesn't break once in awhile, it's not bleeding edge enough! Well done brave Twirters!

May 20, 2011 | Unregistered CommenterChuck Kelly
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