[mythtv-users] Yet another potential FrontEnd

Nick Bright boberz at thewatch.org
Fri Aug 15 22:25:06 UTC 2008


Mike Perkins wrote:
> Fred Squires wrote:
>> On Fri, Aug 15, 2008 at 10:29 AM, David Schlenk <mythtv at schdav.org> wrote:
>>> On Fri, Aug 15, 2008 at 12:05 AM, Jean-Yves Avenard <jyavenard at gmail.com>
>>> wrote:
>>>> 802.11g only the mini ; I wish it was 802,11n
>>>> Can't stream HDTV (1080i) with 802.11g unfortunately ; had to wire the
>>>> menu
>>>>
>>> Not to take this off topic but...
>>> I see this piece of info on the list all the time and often wonder if I'm
>>> breaking the laws of physics or if people actually just have really bad
>>> coverage in their homes. I stream mpeg2 HD with 802.11g all the time.
>>> Typically bitrates from broadcast TV top out around 19Mbps... doesn't g
>>> potentially go up to 54Mbps? Even if you halve that you're still rocking
>>> 27Mbp.. plenty of bandwidth. Of course I'd rather use wired if I have the
>>> chance but g isn't unusable for this task if you spend a few minutes
>>> designing your wireless network effectively.
>>>
>> Just to continue with this off topic discussion.  I've also never had
>> a problem streaming HD with 802.11g.
>> I only have 2 clients, though.
>>
> Your mileage with wireless is going to depend on how many *other* wireless 
> setups are in your neighbourhood. If you are in a densely populated area you 
> will probably have worse throughput than if you are out in the sticks.
> 

Indeed. I operate a Wireless ISP so I am well qualified to comment on 
the subject....

802.11G in a perfect lab environment is only going to ever get about 
20-25Mbps *half duplex* UDP throughput. If you go full duplex TCP you'll 
get about 9-10Mbps each direction, or 18-20Mbps one direction. This is 
WITHOUT considering "Turbo Mode", which usually doesn't work very well, 
because it uses a 40Mhz channel size and has a much, much lower noise 
tolerance than a 20Mhz channel (that's the standard size).

And that's in a Lab. With no other signals detected. Two meters apart.

In your typical home, without direct visual and radio LOS and with 
potential neighborhood access points causing interference your mileage 
is going to vary WIDELY.

Strictly speaking 802.11G _does_ have enough bandwidth to steam HD - but 
  each home is going to have different performance, and not every home 
will have enough throughput to stream HD video.

The quality of your wireless equipment matters too! You're going to have 
better signal quality with more expensive hardware: "You get what you 
pay for".

  - Nick





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