EVDO USB bus power report thread - Why the Y Cable?

tlordon · EVDO Newbie Joined: 09 Dec 2006 Posts: 3

i just got testing the Y cable
direct connect to laptop
and with a 5v 2.5A adapter tied in (cut power from notebook on this setup so not to fry notebook but give more than the usb modem could use).

i saw no impact in speed tests..
I tried this after suffering slower speeds / unstable speeds on the U720 Vs AC595.

so i only need the y cable if my laptop is siting on the side of a desk..(i have vertical USB ports)

ill post more of my reviews of the 3 connection devices in another thread..

oh the u720 is charged as a phone as modem for 49 not a connection card.. for 59

3stepps · EVDO Newbie Joined: 24 Jan 2007 Posts: 4

Supposed to be 5 Volts 500mA. The wye cable gives you 5 Volts at 1000mA or 1Amp. ********Supposedly******** you could supply 10Amps 10,000 mA and it would only draw whats needed. 125mA in standby and 750ma at full power.
_________________
Just cause!

downtube · EVDO Newbie Joined: 05 Feb 2007 Posts: 1

I am new to these forums so please be kind if someone already posted this idea...

If more power to the modem can help in certain circumstances and you don't want to give up both laptop USB ports then can an external USB power supply help here?

http://www.radioshack.com/product/index.jsp?productId=2553285

I was looking to use this device to power my Treo 650 and IPod. I wounder if plugging the second arm of the Y-cable into this device would help to power the modem.

--Michael

Scott · Posted: Tue Feb 13, 2007 7:19 am Post subject:

The only way to know if USB hubs (or direct power supplies) provide more power and thus better throughput with the Sprint U720 and Verizon USB720 modems is to try them.

Not all hubs are of the same quality, some make leak in noise to the circuitry and while their AC adapters may supply more power, that power may be "dirty".

If you test a hub: note the brand and model number.

I am aware that the Ovation USB modems will work in/thru a USB hub. I spoke with someone yesterday who was using a hub with more than one Novatel U720.

Some questions are:

Will the "dirty" power supply for a hub increase noise, thus lowering signal to noise ratio and finally throughput speed? So even though power has gone up, quality of signal has been diminished, lowering performance.

How much is too much? The Novatel Ovation can only use approximately 800 mA. What kind of regulation does the Ovation have onboard and is there a point at which overpowering the device would make it fail (or again, worsen the signal to noise ratio)?