The second Finding from the CISPA Lab. As the traffic increases on a Radio Channel, the amout of Current need goes up greatly. Add a second radio card and it realy goes up.

Replace the Atheros Card with the new 400mw Atheros Card, Build a point to point system with these card and start a stress test using high data rate for a 10 minute timeframe and look at the current rise!!!!. On a many CPU boards, you reach the max current available!!. Add a second radio card and setup NSTREME 2 for Duplex operations and Stress Test, you will see that you need Hover Dam to power it!!!.

What happens is this. The radio cards run out of power, and go into a standby or receive mode causing the link to drop for a few seconds. Then most of the time they come back on line. However, they go on and off; on and off. When you measure the thru put of IP traffic while this is occuring, you get VERY POOR thru put.

ADVICE: you can go cheap at the customer end point! If you are running 1 radio card and only natting, and have only a few firewall rules! You can not GO CHEAP on you BASE STATION, MAIN ROUTERS, BANDWIDTH CONTROLLERS, ETC. If you do, you have trouble.

More finding comming soon from the California Internet Service Providers Association LAB.

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Mark,

Thank you for your contirbution to this forum. I am a fan of your posts and horde them.

Excellent, and thanks to both of you.
I must say that's a subtle point which many could miss - take account of onboard PSU limitations when loading wireless cards on low-power embedded motherboards.
I note the dual-band wireless cards seem to draw a bit more than the 'g-only' variants, so I guess the problem is really at the CPE end.

Regards

so how much power do we need .

running a ap base

p4 2.0 processor
DC-DC convertor
40'pole and
1 or 2 400mw 5414? cards

Randy

That's no low-power system!
A P4 processor can take up to 100W I think .... makes consumption of other items "tiny" by comparison.
Probably best to fire it up "on the bench" and put a DVM in-line with the power, read the current, and calculate the watts.
I think there are some online power calculators for popular motherboards, you could try there. That would help predict.

Regards

These might server as a starting point.

http://64.233.167.104/search?q=cache:q7 ... ator&hl=en

http://www.jscustompcs.com/power_supply/

we dont use poe for our base units direct dc-dc convertors are used .

i figure a 150watts is what we need for a consistant draw. so what is the draw of the 400mw cards ? and what type of cooling system should we use . mild temps.

we have had issues with keeping units koolin a 4r case. Cisp was talking about coolers . i tested one but seemed to get to hot. meaning the cooler kept things kool for a while but then over heated it self still working on this .

Randy

Transmit - 4.7W +/- 300mW
Recieve - 1.2W +/- 200mW

http://www.ubiquiti-networks.com/sr5/sr5_datasheet.pdf

Our Power Supply system in Use here (CISPA LABS) is a 220watt DC-DC converter. We do not use POE, we use the Belden Cat5e Cable with 2 #14 guage Leads. Standard order item from Belden Wire and Cable.

For Cooling, we use a Solid State Heat Pump which we build. It is designed to cool, and / or heat the system depending on the temp.

We run between -40F and +125F on our system.

My advice to you is this. CPE equipment is 90% fine for POE.

Everything else, DO NOT WASTE YOUR TIME

markon

do you sell your heater/chiller system . we use something similar in cctv industry for camera systems.

if so can you email me

randy
randy@srsnetworks.net