[MLB-WIRELESS] 1.2 MBytes/S on 10k link (was New Node to be)
wireless at smithsgully.net
Thu Jun 8 22:28:44 EST 2006
We've been doing some more tinkering on the 3 hop system described below.
Discovered the Edimax link wasn't running at its full potential due to
problems with POE. There is a very long run of CAT5 and the voltage drop
was excessive. This caused the switchmode power supply in the Edimax to
draw more current which causes more voltage drop which causes more current
pull and round we go again..... In the end the AP was only just working and
even dropping out occasionally when the mains voltage dropped below 215V at
There was only 8 volts at the output of the plugpack and less than 5 at the
AP. Swapped the plugpack for a better regulated device and we have close to
12V at the AP now.
So now with the power fixed, the 3 Km Edimax link runs at...... 1015 KBytes
And I think we might be able to squeeze a bit more out of it with a better
antenna. We get best throughput with the radios running at 18 Mbps so it
seems we may be running out of signal.
With the problems of proximity at Blackburn I shifted the channels to 1 and
11 rather than 6 and 11 for maximum separation.
And now for the results over the 3 hops.......
Using wget to do a HTTP transfer of an 85 MByte file.
800 KBytes / second. (peaking to 850) over 10 + 15 + 3 Km.
> 1) Templestowe Lower to Kangaroo Ground - 10 KM
> 24 dB Gridpack each end
> Throughput 1.2 MBytes/S
> Radios: Sparklan WX6800 (= Linksys WAP54G = WRT54G minus Switch)
> Firmware: OpenWRT-Freifunk Ver. 1.1.4 (You should be able to achieve
> similar results with OpenWRT)
> dctrl 16000
> 24 MBPS radio rate
> Wireless Mode: Ad Hoc
> CTS protection disable
> Frame Burst enable
> Radio Mode = G Mode Performance (Whatever that means!)
> Frag Thresh 2346
> RTS Thresh 2346
> 2) Kangaroo Ground to Blackburn North - 15 KM
> 19 dB panel to 24 dB Gridpack
> Throughput 1.1 MBytes/S
> Radios: WRT54G
> As above except
> dctrl 22000
> 18 MBPS radio rate
> IMPORTANTLY the units are set up to route IP NOT bridge Ethernet. i.e.
> The bridge is disabled between wireless and Ethernet and the interfaces
> have separate IP addresses in different subnets. Using bridging we got
> only 35 KBytes/S with the other parameters identical. There is a big
> problem with the bridging. Peter Buncle had similar results.
> We also have a number of the standard Freifunk init scripts disabled,
> firewall crond dnsmasq olsrd rdate olsr-prio.
> With the two hops above strung together we get 900 KBytes/S.
> A third hop which is only 3 KM uses Standard Edimax radios in bridge mode
> with a Vagi and a dodgy Galaxy antenna and runs at 600 KBytes/S. All 3
> Hops strung together run at 500 KBytes/S limited by the worst hop and the
> fact that the antennas are less than half a metre apart.
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