USB Modem Power Issues / USB Extensions

My black usb speedstick keeps on disconnecting from my computer as if it is removed from the computer and then plugged back in. I have tried a cable, powered hub and straight into the m/b, but to no avail. It usually happens after surfing for an hour so browsing facebook, news articles etc.

Any ideas what might cause this?
 
Jacques_mybb said:
My black usb speedstick keeps on disconnecting from my computer as if it is removed from the computer and then plugged back in. I have tried a cable, powered hub and straight into the m/b, but to no avail. It usually happens after surfing for an hour so browsing facebook, news articles etc.

Any ideas what might cause this?
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Sounds like a power issue to me. My E272 used to do the same on Vodacom if I used a 1.8m cable and bittorrent, normal browsing was fine. The problem never occurred using the supplied short USB cable.

What is your signal strength (RSSI), see here?
 
ginggs said:
Sounds like a power issue to me. My E272 used to do the same on Vodacom if I used a 1.8m cable and bittorrent, normal browsing was fine. The problem never occurred using the supplied short USB cable.

What is your signal strength (RSSI), see here?
Click to expand...

RSSI is -67dBm
 
Speedstick and USB extention

I only partially enjoy the higher internet speeds with the 7.2Mbps speedstick. Since my desktop is not very "movable", I was advised to use a USB extension to see whether reception could be improved by moving the speedstick around. When using a 1.2m extension, I receive an error message - the system does not "see" the speedstick. Is this unusual? Is it the quality of the cable? Any thoughts? :confused:
 
its the cable most likely.

I know for sure that belkin's dont work well with speedsticks etc. Make sure it's a high power/speed cable that supports usb 2.0 properly
 
Problems running Black Cell C modem with USB extension cable

Im haveing issues running the modem using a extension cable.

once its connected, its fine... no disconnections.

sometimes after I have switched my PC off, it doesnt seem to detect it properly, i haveto plug it in and out a few times and HOPE it picks up.

could it be a USB power issue?
 
i think it is a power issue. i also had trouble when i used an extension cable. it wouldn't connect for longer than a few seconds.
 
How to fix "power" issue? It worked before, but after OS re-install it stopped working at all.
 
the long cable is the problem, I have had the same problem, current is lost as usb is mit a heavy duty power line, milliamps are lost and then the device cannot power up.
 
See this thread on the Huawei forum. A DIY hardware patch using a Schottky diode and two capacitors fixed the problem that the modem gets "undetected" from USB port in that the power to the modem is stabilised. His fix works for cheap USB extensions as well and some report the modem running cooler.

This is quite likely the same problem we're having with the Cell C modems.
 
ajax said:
See this thread on the Huawei forum. A DIY hardware patch using a Schottky diode and two capacitors fixed the problem that the modem gets "undetected" from USB port in that the power to the modem is stabilised.
Click to expand...
Interesting link, thanks. This circuit specifies a 100uF capacitor, I did a quick search and it seems the maximum decoupling capacitance specified for USB is only 10uF, so you may damage your port or modem with this.
 
ginggs said:
Interesting link, thanks. This circuit specifies a 100uF capacitor, I did a quick search and it seems the maximum decoupling capacitance specified for USB is only 10uF, so you may damage your port or modem with this.
Click to expand...

Why the 2 capacitors in parallel I also don't know. Capacitance in parallel adds, so you end up with just 103.3 uF in that circuit. I think just adding a 10 uF across line 1 and 4 should do the trick.
 
ajax said:
Why the 2 capacitors in parallel I also don't know. Capacitance in parallel adds, so you end up with just 103.3 uF in that circuit. I think just adding a 10 uF across line 1 and 4 should do the trick.
Click to expand...
Electrolytic capacitors like the big one don't react well to high frequencies, but tantalum and ceramic capacitors do, so it's common practice to use both types in parallel.
 
A couple of years ago I played with a Sierra Wireless AirCard 875U:
http://mybroadband.co.za/photos/showphoto.php?photo=20881
The Sierra Wireless AirCard 875u includes an in-box battery Lithium Polymer that is to be inserted under the face plate. The battery itself provides additional power when the device is in fringe coverage or in a heavily loaded network ensuring that the connection remains stable, prevents the host from freezing, and prevents the device from resetting. Other USB modems get around this issue by providing a Y-cable accessory that attempts to draw power from 2 USB ports the AirCard 875u plugs directly into a single USB port and does not require any additional cables. The battery trickle charges from the USB port when not in use and is expected to have the same impact on notebook battery drain as other LaptopConnect cards.
Click to expand...
 
Instead of increasing the power to the modem, why not try and reduce the power requirements of the modem by using an external antenna?

I would go so far as to suggest that anyone using a wireless technology for internet access from a fixed location should be using an external antenna, not only will it improve your internet experience, it will make your modem run cooler and last longer.
 
I just got a 5m USB extension Cable from Zakk Speed. It was a bit pricey at R200 but it seems to work like a charm. It improved my signal from -91dbm to -75dbm because it allowed me to move it to a better spot. I tried the belkin one from Incredible but that didn't work so well and that was only 1.8m! Anyone who needs an extension I'd recommend the Zakk Speed one!
 
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