O2 & Vodafone USB Wireless

bcstrat33

Hi all,

Does anyone have any info/feedback on either of these wireless USB broadband systems (this is the USB dongle for wireless broadband, no landline or antenna needed...I think)?

Thanks.

donaghs

I've used them very effectively as part of work when I was out of the office (Dublin city centre). People in my work use them for Outlook and web browsing over VPN, so it must be stable enough when there is a good reception. One disadvantage is that you can only use it with one computer at a time. But on the other hand, it's handy to carry around with your laptop.

But a friend of mine is having issues in Ranelagh/Rathmines. He says coverage and speed are terrible. This improves if he moves the 3G modem and laptop up against a window, but this is very impractical for him. I know there is a short cable with 2 USB connections which is meant to boost the signal. This does not work for him though.

Does anyone know if you can get a metre long USB cable which would help improve the broadband situation by reaching the Window? (but not have an adverse affect by not getting enough electical power).

wazzoraybelle

I believe you can use up to 1.5 metre cable without any signal loss the one I use has that black little barrel near one end to limit interference.

The cable that has two connections at one end is for USB 1.0 which isn't as powerful as USB 2.0.

watty

nope.
The two connections is simply for more electricity.
It does make no difference to Speed.
Even USB 2.0 still only specifies a maximum of 500mA per port.
If the USB modem needs more transmitter power it could overload one USB port and the laptop might disconnect it. plug both wires in.

donaghs

Thanks. So you're saying you can get a 1.5 metre USB cable to use with these small 3G/HSDPA modems, with 2 USB connectors to plug into your PC?

watty

To avoid risk of voltage drop, I'd use two heavy USB cables on the double cable end.

I've dismembered some USB cables (that worked badly) to discover they where really minature four core alarm flex, i.e. no screen, power & ground too thin and D+, D- data pair not twisted. Also alarm colour code and not the USB colour code.

The USB spec actually forbids extension cables but they are sold for the USB WiFi dongles. Never use them to extend a regular length cable or you may get data corruption.

bcstrat33

Thanks!

Does anyone have any information on transfer rates i.e best/worse case upload/download speeds & contention ratios??? I'm finding it hard to get this information from the provider's website.

Also, does the weather affect this system?

Cheers for the response.

watty

yes. heavy rain and snow (!) falling affect it reducing signal a bit.

Upload 14kbps to 100kbps O2, maybe up to 384kbs Vodaphone. Typically around 70kbps on O2
Download 14kbps to 1800/3600/7200 kbps depending on mast, modem and upgrades. Typically around 850kbps on O2, but I'm in a rural area 800m from a mast, with a 2nd set of masts to cope with extra traffic on Race meet days.

Contention is meaningless as is it mobile. They can NOT control how many people are in a sector and want to connect. Contention is NOT max conections.

On DSL with 1000 users and 48:1 contention you get connected and your speed reduction is never as bad as 1/48th as with so many users all are not doing stuff at same time. The 48:1 is spread over ALL the users on the exchange.


On Mobile Phone Masts, you might have 100 users in a sector. Only the first 24 can connect at all. the other 76 get no connection.

Max connections (not the contention) is 12 per 1.8Mbps, i.e. 24 on 3.6Mbps masts and 48 on 7.2Mbps masts.

Because it uses CDMA, as more users connect the apparent noise level rises so cell size shrinks leaving those toward edge of range unable to connect (Called "Breathing" ). This also means that if sector speed is 3.6Mbps (3600kbps) and 20 users connect you get worse than 3600/20 (=180kps), I think but could be wrong that in such a case unless you are near mast your speed could be close to 60kbps.

So apparent contention for connected users is equivalent to nearly 48:1 but unlike contention on Fixed wireless or DSL you will experience contention effect more often so it is much more like 200:1 contention on DSL. Also unlike Fixed wireless and DSL or Cable there is unknown level of contention to connect at all which could be anything from 1:1 to 10:1 and is not fixed. This is contention where the 3 out of 4 get nothing, if the there is 100 users trying to connect.

If there is no 3G signal the max speed on GPRS is maybe 60kbps and on EDGE (O2, not Vodaphone) 230kbps. Minimum is 14kbps.

Latency is 150ms to 999+ ms (ping times or delay) depending on number of users. Further away sites more delay of course.

whitelightrider

Which company would be better to use - Vodafone or O2?

whitelightrider

Anyone have an idea which one would be better?

jor el

Depends on where you are, what you need and how much you're willing to pay. Best for one may not be best for someone else.

They both offer trials, get them both and try them out together, over the weekend would be a good idea. Keep the one that you think is best.