What do the numbers mean?
The number returned by the AT+CSQ command gives you a more accurate measurement of signal strength. The following table lists the dBm equivalent measurements (note that the dBm measurements are negative, so a higher negative number represents a lower signal strength):
0 < -113 dBm (Marginal) 1 -111 dBm (Marginal) 2 -109 dBm (Marginal) 3 -107 dBm (Marginal) 4 -105 dBm (Marginal) 5 -103 dBm (Marginal) 6 -101 dBm (Marginal) 7 -99 dBm (Marginal) 8 -97 dBm (Marginal) 9 -95 dBm (Marginal) 10 -93 dBm (Workable under most conditions) 11 -91 dBm (Workable under most conditions) 12 -89 dBm (Workable under most conditions) 13 -87 dBm (Workable under most conditions) 14 -85 dBm (Workable under most conditions) 15 -83 dBm (Good) 16 -81 dBm (Good) 17 -79 dBm (Good) 18 -77 dBm (Good) 19 -75 dBm (Good) 20 -73 dBm (Excellent) 21 -71 dBm (Excellent) 22 -69 dBm (Excellent) 23 -67 dBm (Excellent) 24 -65 dBm (Excellent) 25 -63 dBm (Excellent) 26 -61 dBm (Excellent) 27 -59 dBm (Excellent) 28 -57 dBm (Excellent) 29 -55 dBm (Excellent) 30 -53 dBm (Excellent) 31 > -51 dBm (Excellent)
So what do these numbers mean?
- Marginal – Levels of -95dBm or lower. At these sort of levels, it is very likely that you may suffer low throughput and disconnects due to cell loading/breathing even with an outdoor antenna.
- Workable under most conditions – Levels of -85dBm to -95dBm – Probably worth considering an outdoor gain type antenna. Could suffer poor throughput and disconnects due to cell loading/breathing.
- Good – Levels between -75dBm and -85dBm – normally no problem holding a connection with this sort of level (even with cell breathing) without the use of an external antenna.
- Excellent – levels above -75dBm. Should not be affected by cell breathing/loading and should not require an external antenna.
For those who are technically oriented, as most BB Users are, and want MORE, here is an approximate tabulation of the # of Bars vs. signal level in dBM:
1 bar ~ -102 to -120 dBM
2 Bars ~ -93 to -101 dBM
3 Bars ~ -87 to -92 dBM
4 Bars ~ -78 to -86 dBM
5 Bars ~ -40 to -77 dBM
| Signal Bar Strength Indicators | RSSI Indicators |
| 5 bars (optimal strength) | -77 or higher |
| 4 bars | -78 to 86 |
| 3 bars | -87 to -92 |
| 2 bars | -93 to -101 |
| 1 bar | -102 or lower |
