Actually this is not about upstream speed but about the problem that the device will completely lose reception if the uplink signal doesn't reach the cell tower anymore. Despite your device may be able to "hear" the cell tower it may not be able to register on the network because your device speaks too quietly so the cell tower can't hear it anymore. User devices can only emit their signal with a few mW, the cell tower however has fast more transmission power. So there is an inbalance in transmission power making the uplink the bottleneck. That's why an external antenna should also be user for transmitting and not just for receiving.
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Dtac Wave Aircard Not 3G Compatible?
Started by BuffaloRescue, 2011-12-31 21:24
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30 replies to this topic
#27
lomatopo
Titanium Member Posted 2012-02-03 09:19:31
Actually this is not about upstream speed but about the problem that the device will completely lose reception if the uplink signal doesn't reach the cell tower anymore. Despite your device may be able to "hear" the cell tower it may not be able to register on the network because your device speaks too quietly so the cell tower can't hear it anymore. User devices can only emit their signal with a few mW, the cell tower however has fast more transmission power. So there is an inbalance in transmission power making the uplink the bottleneck. That's why an external antenna should also be user for transmitting and not just for receiving. Good to know, do any air-cards provide and external antenna connection which supports both Tx and Rx? #28
inquisitor
Newbie Posted 2012-02-03 17:09:32
Unfortunately I'm not aware of any multiband 3G modem with a fully working external antenna connector.
#29
lomatopo
Titanium Member Posted 2012-02-03 17:29:19
Unfortunately I'm not aware of any multiband 3G modem with a fully working external antenna connector. OK, thanks. It seems like some people (based on a very cursory review of threads in technical forums like Howards, etc.) do notice an improvement in download speed when using an external antenna. And I believe many people here experienced improved performance using external antennas with CAT CDMA2000 1xEV-DO, but perhaps those air-cards do allow for both Tx and Rx? It sounds like, with "Rx Diversity" when you plug in an external antenna to continue to use the internal antenna for transmitting, but you enable a switch which allows the external antenna to be used for receiving, at least on the Huawei gear. #30
inquisitor
Newbie Posted 2012-02-03 20:10:15
Yes, an external antenna will usually improve download speeds even if you have full reception. The data throughput in HSPA networks is very sensitive for reception quality - just google for "Receive diversity helps maximizing throughput in HSDPA networks" for an detailed article on how important diversity is for HSPA. Despite modern 3G modems mostly having already an integrated second antenna for diversity the improvement from diversity increases when using a detached external antenna. This is like watching a soccer game in a stadium - if you watch it alone you may not see the ball all the time due to the heads of the spectators in front of you obstructing your view. If you have a friend sitting next to you, he may see the ball sometimes even when you can't see it as he has a slightly different perspective and so together you see more from the game but sometimes you will still both miss the ball. If you have a really tall friend sitting in another block of the stadium (an external antenna) it is very likely that together you will see the ball all the time. I hope this example is understandable.
#31
TwentyBaht
Senior Member Posted 2012-02-11 16:46:37
inquisitor, Iomatopo,
Received the Huawei E182e (1899 baht delivered) from Morgan Computer at Pantip. Went to Chiang Rai "Central" Dtac store and got a sim activated. First, the 20 hour/month package (105 baht) just to test bandwith, Chiang Rai, Mae Sai, Chiang Khong. Inserted the Dtac sim. Booted laptop. Installed "Mobile Partner" from the aircard. (Profiles for TOT, Dtac, others already in the program.) Clicked on Dtac, and was online. Bandwidth, about 200k in Chiang Khong (EDGE only). Plan on testing in Chiang Rai next week. And, Mae Sai. (As information, a Thai acquaintance there says Cat 3G and Dtac 3G are good in Mae Sai.) Probably, get the 399 baht/month plan when finish testing. And, look at an antenna for remote areas. Thanks again, for all your help. |
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