External Antenna Problems with USB Connect 881

Contributor

External Antenna Problems with USB Connect 881

I live in a rural area without DSL or Cable service and I have a USB Connect 881 which I recently purchased for a residential internet connection. The device itself works very well.

 

Shortly after purchasing this modem I purchased an External 9dB gain antenna from CellGearUSA from their EBay Store. The problem is when I have the antenna hooked up I have issues staying connected and constant disconnects. Without the external antenna I have a signal strength of -83dBm to -86dBm and I stay connected for as long as I want (I think I had a max time of being on AIM for 4 days with no disconnect) When I connect my antenna (which I have outside and I use a USB Extension cable) I have a signal strength of -73dBm to -76dBm. I have tested the USB Extension cable and it is not causing the issue because I disconnect the modem from the USB cable and antenna and reconnect it to the USB extension cable and I once again I have the lower signal strength but I stay connected for as long as I want.

 

I have a WindowsXP SP2 OS and when these disconnects happen I get the sound wave (from windows) that a device has been disconnected and reconnected. This "wave spam" goes on for approx 5 to 10 seconds during which time 3G Watcher / AT&T Communication Manager cannot find a wireless device. After this event stops it re initializes the device and I can usually reconnect immediately without issue. Occasionally in order to reconnect I have to disconnect the modem and reconnect it.

 

This problem is frustrating me because I do not think it is caused from a faulty antenna because if the antenna itself would be faulty it shouldn't cause the device to actually "disconnect" and cause the OS to believe it was disconnected.

 

Any help would be greatly appreciated.

Thank You

11,896 Views
Message 1 of 8
BAT
Scholar

Re: External Antenna Problems with USB Connect 881

I would suggest, at first, verify that ALL your USB devices has the power save turned OFF.

Under the Devices Management, select the USB trees, select properties.

 Look for the Power Management Tab. Unselect  -- Allow the computer to turn off this device to save power --

Hope this helps..

BAT
Message 2 of 8
Contributor

Re: External Antenna Problems with USB Connect 881

I now have a new problem which I think I already know the answer to and the problem may be the cause of my other problems.
 
My power light on my modem went red last night and stopped working with or without the antenea. However, when I hooked it directly to my computer ( without the entension cable ) it fixed the problem. I have it hooked back up to the extension cable now with a green power light ( after having it hooked to my computer for several hours ) and now for some reason it 'appears' to be working with the antenea.
 
I have a feeling that the entension cable isn't providing the full 5V of USB power because of resistence and that slowly lowers the battery of the device causing it to malfunction and if the antenea uses more power than the built in antenea ( if it actually uses 'power' to do so, most devices do not ) this could be the root of my problem.
 
As to your post BAT all of my 'USB Root Hubs' have that option already selected. I also found out when looking for this that the device requires 500mA and that is exactly what it says is available so if the extentsion cable is causing enough resistence it could lower what it says is required by the device.
 
I think I may have solved my own problem, only time will tell to see if the power light goes red and the antenea stops working once more.
 
However, knowing the problem is only part of the battle. Now I must find a soultion that hopefully doesn't involve me switching it back and forth from my computer to the extension cable every day.
 
Thanks
Message 3 of 8
Voyager

Re: External Antenna Problems with USB Connect 881

Have you tried using a powered hub?
Message 4 of 8
Contributor

Re: External Antenna Problems with USB Connect 881

When I asked why the 881 had a battery, the salesman told me that's so you don't have to worry about the USB going Off. Is that true, or could that still be the user's problem? I'm considering getting an antenna and don't want the same problem(s).
Message 5 of 8
Former Moderator

Re: External Antenna Problems with USB Connect 881



wfotto wrote:
When I asked why the 881 had a battery, the salesman told me that's so you don't have to worry about the USB going Off. Is that true, or could that still be the user's problem? I'm considering getting an antenna and don't want the same problem(s).


Here is the explanation from the AT&T Knowledge Base:
 
"Remove or Insert the Battery for the AT&T USBConnect 881"
 
The AT&T USBConnect 881 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 AT&T USBConnect 881 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.
Message 6 of 8
Contributor

Re: External Antenna Problems with USB Connect 881

I haven't had much time recently to investigate this more but I did take a few more steps to find out what is going on with the extension cable.

 

Thinking that my problem was due to not enough power I broke out the multi-meter and tested the voltage and amps coming directly out of my computer and out of the extension cable. They are almost identical and still both within specs of USB (5v, 500mA) I am at a complete loss as to what my problem is coming from. I tried to contact AT&T and after listening to my problem they immediately referred me to Sierra Wireless. After spending two hours on the phone with the Techs (I went through 2) they didn't know either and just ran me around in circles. They however did constantly repeat the phrase "We don't advise using extension cables".

 

I intend to try a powered USB hub but I don't see how that will help in any way when the voltage and amperage coming out of the extension cable are both on par. However, it will allow me to rule out that one slim possibility of a problem.

 

I also recently found out a neighbor of mine has this exact same PC Card and I will be borrowing his antenna to see if it causes the same connectivity problem mine does. If the powered USB hub and the different antenna fixes the problems I will be set, if not I go back to the drawing board once again.

Message 7 of 8
Highlighted
BAT
Scholar

Re: External Antenna Problems with USB Connect 881

I might have figured it out, I seem to have a problem when I use the internet for a long time, the red light comes on and the device powers off.
This is what I have concluded, the USB wireless device uses more power then the USB port can provide, so it uses the battey, BUT for heavy users (like myself) the battery power runs low then it loses power, IF I don't leave it connect to the laptop, and give it time to charge up, then the nex use, its battery is still low, and drops out again.. My solution is to plug it in a USB charger, I just so happen to have a battery charger that has a USB port on it to charge MP3 plays.. After I charge it up, it works fine, until I get to the 4-5 hrs of use..

Let me  if  you try this and it works, or  just leave it pluged without use, to allow it to charge.. I have even used the, power rado OFF,  feature  in the  software..

Hope this helps

BAT
Message 8 of 8
You must type a description before you click preview or reply.
Share this topic
Announcements

Are you looking to upgrade and activate your device?

Let us help make Ordering, Upgrading and Activating easy!

Additional Support