Signal Strength Matters
February 11, 2008
The strength of your cellular signal is measured in dBm units, a decibel-based power unit. If you are running the connection software that comes with your cellular modem, it probably shows your signal strength in the typical “four bars” graphic, which roughly correlates to pre-defined dBm levels. The term dBm is abbrreviated from the logarithmic power ratio with respect to 1 miliwatt. On the other hand, the term dBi which is usually used in external antenna description, implies the logarithmic power ratio with respect to isotropic power (ideal).
Sierra datacard user can see the precise signal strength in dBm units by hovering their mouse over the “four bars” graphic at the top of the 3G Watcher window. Other providers offer similar methods for viewing signal strength with more precision than the bar graph. Measurements are in negative integers, so the closer your dBm is to zero, the stronger it is. Generally speaking, a very strong signal strength would be greater than approximately -70 (again, greater meaning closer to zero). A very weak signal strength would be lower than -100. Worse than -105 and you will probably experience erratic, unstable performance, while worse than -117 may drop you offline.
Because dBm units are logarithmic, a +3 dBm increase represents a doubling of signal power while a -3dBm decrease represents a halving of power. Therefore, even a “small” change in dBm can represent a significant change in actual broadband performance.
Later when you experiment with an antenna, you will want to view the dBm reading as it changes. There is a short lag between movements of the antenna and updates in readings. It is also typical for the dBm to fluctuate, sometimes significantly, so you will want to look for an average reading over a minute or two.
Finally, you may receive the same broadband performance over a range of dBm readings. For example, you might find that a signal strength of -75 does not produce any faster speeds than a reading of -82, but that -82 is much faster than -90. This will vary by base station. You should test your network speeds at any of the many broadband speed test sites to find the most realistic balance of performance and signal strength for your location.
Cellular data modems are sold in two form factors—PC cards for insertion into laptop computers, and USB “sticks” which can be plugged into either laptop or desktop machines. The most important thing for boosting reception is that your cellular modem feature an external antenna jack. Many models do, but without one your signal-enhancing options are of course limited.
Although USB modems might be a tad bulkier for laptop use, these modems offer more flexible positioning options. At the very least, you might find that plugging a USB modem into a USB extension cable can let you place the modem near a window for a slight boost in some situations.
While many cellular modems do include external antenna jacks, the jacks themselves differ in shape. Before connecting any external antenna apparatus, you need a cable that plugs into your particular modem’s jack at one end, and terminates in a more standard connector at the other end.
These short cables, sometimes known as “adapter cables” or “pigtail cables” can sometimes be ordered directly from your cellular vendor, and may be used to adapt different type of external antenna to different modem. For example, external antenna for Sierra to be adapted to Option modem.
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Posted in 3G
February 18th, 2008 at 12:44 am
salam.. ada kemusykilan yg saya nk tanya ttg signal sierra 875 ni..
1). Signal yg tertera pd 3g watcher menunjukkan ada capaian HSDPA..adakah
signal tersebut menandakan bahawa terdapat aliran data 3.5g yg berlaku pada rangkain 3g saya..Saya hanya melanggan celcom D68 384kbps..
2). Petunjuk pada ’signal strength’ -110dBm .. Bermakna tiada aliran data yg boleh diterima.,akan tetapi saya masih boleh melayari internet .. Adakah terdapat masalah pada system 3g watcher yg saya gunakan?
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February 18th, 2008 at 8:59 am
Zahid
Based on my experience (i’m in HSDPA coverage but down grade to D68)
1) Yes, sometimes you can have speed exceeding 380k, up to 500k. Some reports speed of over 700K. But mind you the speed is not always “over”, as long as the signal strength is over 4/5 bar
If I’m using Flashget to download, I can see the speed “yo-yoing” from 46-90K. Optimum 3G speed download via Flashget will be about 48K
2) if my signal shows over -100dBm, i’ll be kicked to HSDPA stream. Yes, still can browse, but 3G is way better.
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February 18th, 2008 at 8:53 pm
Dear Admin,
Kawan saya menggunakan sony vaio, os xp home edition service pack 1. Saya cuba install 3g watcher tapi tidak berjaya, kenapa ya Admin?
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February 19th, 2008 at 10:41 am
labi36 – please upgrade your os to service pack 2. it won’t works on service pack 1.
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February 19th, 2008 at 1:45 pm
to zahid, kalau -110dBm ubatnya beli external antenna. boleh conect tapi sekejap saja kena tendang.
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February 28th, 2008 at 11:23 am
Salam….
HELP !!!….
Saya baru sign up ngan Celcom BB. Using Huawei E220 modem.
From the first time connected, speed internet saya sgt slow. Kalau download attachment from email pun slow , about 8.0-9.0 kbs jer…tambah la kalau DL from any website….speed mmg tak penah lebey 15 kbs..tu paling tinggi la..
Tapi kt dashboard die tunjuk saya ada 4 bar signal UMTS. Also currently living in Kota damansara.
From saya baca in this blog/comments, most ppl yg pakai celcom bb ckp ALthough celcom BB not tat fast..diorg managed utk dapat speed from 40kbs-100 sumthing…
SO….soalan saya….do i have to do any CONFIGURATION? atau settting ke kt modem tu? atau apa apa advice from anybody on how to get faster speed than current. It is reallly FRUSTRATING….connection slow…..modem mahal….package mahal (98 permonth)…..help anybody?
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February 28th, 2008 at 4:51 pm
Saya masih mencari external antenna utk Novatel Merli XU870 sy.. Admin dah ader stok tak antenna jenis ni..
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February 28th, 2008 at 5:21 pm
Dear Tina: Dari comment tuh sy boleh wat conclusion camni,signal awk mmg xder masalah since dashboard showed 4bar connection,mslhnyer sekarang adalah connection internet tuh sendiri,so solution dier call careline Celcom 1111,sedikit panduan apabila call operator :
1. Apabila bercakap dgn perunding perkhidmatan mula2 tanya no id dan nama operator tuh(untuk wat reference nanti)
2. Dan ayat biasa yang digunakan,”terdapat gangguan network laa cik”-pedulikan itu semua,ckp kat operator tuh sy nak buat kes untuk Celcom Broadband nie,tolong buatkan kes untuk sy.
3.So bagi description masalah anda kat operator tuh.
4.Dlm masa 3 hari,technical team akan telefon anda by personal untuk resolvekan masalah anda.
Dear Hanes:
Agak susah untuk dapatkan antenna untuk Novatel nie.You try search thru ebay ker pastu bg saya link,maybe sy leh deal ngan supplier tuh untuk shipment byk.Kalau kat ebay international,kalau beli satu unit jadi mahal,leh beli bulk purchase murah skit.
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February 28th, 2008 at 9:45 pm
Saya ada jumpa dalam ebay antenna (13dBi) utk novatel. ni link dia
http://cgi.ebay.com.my/13dBi-External-Antenna-For-Novatel-Merlin-XU870-EX720_W0QQitemZ360014044398QQihZ023QQcategoryZ20380QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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February 28th, 2008 at 9:46 pm
sorry for the improper link
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February 28th, 2008 at 9:55 pm
Hi Tina, sudah set “3G Only” ke kat connection configuration? Kadang2 connection jadi slow sebab ianya menggunakan gprs instead of 3G. Cara2 nak setup E220 ada kat 3G Forum tuh under Installation Support @ http://myceloteh.com/3gforum/viewtopic.php?f=3&t=7
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April 2nd, 2008 at 12:52 am
I’m looking for an external antennae for my option gt max pcmcia datacard. Do you keep stock for this type of antennae ?
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April 2nd, 2008 at 1:45 am
We didn’t sell the antenna for option,but you can search thru lelong,if i not mistaken the option antenna cost you about RM90 for 5dB gain.
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April 9th, 2008 at 6:11 pm
ghufxpert, external antenna utk novatel merlin XU870 dah ade jual tak? sy betul2 perlukan ext antenna skrg ni cz celcom network makin byk problem. Ade sesape yg tahu tak?
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May 16th, 2008 at 1:43 pm
sy pakai maxis mf600 punya..
boleh x ia ditukar kepada celcom?
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May 16th, 2008 at 6:36 pm
Dear Sya,mmg boleh pun kalau nak tukar ke Celcom,cuma tukar apn sahaja ke celcom3g.
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November 30th, 2008 at 12:07 am
bagaimana meningkatkan kepekaan/booster signal pada huawei e220? perlukah antenna tambahan?
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November 30th, 2008 at 8:10 pm
yup. tapi antenna tu susah nak cari kat msia ni. nak import pun tak berbaloi sebab harga die tggi n gain die pun tak banyak. baik buat antenna sndiri. tapi warranty burn la.
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July 27th, 2009 at 5:29 pm
Salam admin.
sy mencari external antenna 881u.ada tak yg lebih dari 7dbnye external antenna?kat mana nak beli ya?sbb sy duduk kat apartment n bilik belah ke dalam.jadi signal slalu drop.
TQ
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