Hi Neil, I wasn’t going to attempt a reply as it involves a fairly complex reply. Not knowing what Modem or how it displays its settings/readings. I mainly deal with Apple Wi-Fi Networks this might helpful explanation to you… or not ;-) --- RSSI (Receive Signal Strength Indication), is the relative signal strength in a wireless environment in arbitrary units. RSSI or received signal strength indication can go from 0 to -100 (for Apple - other vendors can measure it differently as RSSI has no stated units)
Apple appears to have decided to use a less negative number (closer to zero) to mean a stronger signal. Signal-to-Noise Ratio (SNR) One option in determining where to best place your AirPort base station is to measure its signal quality from a wireless client. In theory, where the signal quality is best would make for ideal candidates for placement. This would hold true for a single or multiple base stations in an extended wireless network. One method to calculate signal quality is to compute the Signal-to-Noise Ratio (SNR). SNR is the signal level (in dBm) minus the noise level (in dBm). Both of these values are typically represented as negative numbers. For example, a signal level of -53dBm and a noise value of -90dBm would yield an SNR of 37dB (i.e., SNR = Signal - Noise = -53 -(-90) = 37) The calculated SNR value, as measured from a wireless client, would decrease as the range to the base station increases due to applicable free space loss. Also an increase in RF interference from microwave ovens, cordless phones, walls, ceilings, etc, which would increase the noise level, would also decrease the overall SNR value. SNR Guideline 40+dB = Excellent signal 25dB to 40dB = Very good signal 15dB to 25dB = Low signal 10dB to 15dB = Very low signal 5dB to 10dB = Little or no signal The following are two methods to take signal & noise level readings: Method 1 - Using iStumbler Download and install a copy of iStumbler <http://istumbler.net/>. Use iStumbler's Inspector feature (select Edit > Inspector from the iStumbler's menu) to take the signal and noise level readings. Method 2 - Using OS X System Profiler / System Report Click on the Apple icon on the menu bar > About This Mac > More Info >System Report > Network > Wi-Fi - Interfaces > > Current Network Information > Find your wireless network > Signal / Noise Jot down the numbers that you see here, for example -50 dBm / -90 dBm SNR = Signal minus Noise, so using the example below: -50 dBm - (-90 dBm) = 40 dB SNR Regardless of which method you use to gather the reading, you would plug them into the SNR formula. The desired goal value is an SNR of 25+dB. At this SNR value, wireless clients should be getting reasonable throughput performance with the base station. This is also the value you would want at the location where you would want to place a second base station to extend the first if you are planning on extending the wireless range. Then use the familiar chart to evaluate your signal quality. • 40dB+ SNR = Excellent signal • 25dB to 40dB SNR = Very good signal • 15dB to 25dB SNR = Low signal • 10dB to 15dB SNR = Very low signal • 5dB to 10dB SNR = No signal As you might imagine, the SNR will change in relation to the location of your Mac laptop to the router If you are getting SNR values of less than 25+dB at the client, either try to locate the source of the Wi-Fi interference or try relocating the base station until they are within a 25+dB range. — My Airport ’Simultaneous Dual-Band 802.11n Wi-Fi 5GHz /2.5GHz’ Network. Option click on Wireless Menu shows my 5GHz RSSI: -55 dBM Noise: -95 dBM Tx Rate: 300 Mbps MSC Index: 15 • Transmit Rate: This is the max network speed available with the current signal strength. The data rate is measured in Mbps. • MCS Index: Short for Modulation and Coding Scheme, MCS is only associated with 802.11n networks. Hope this makes sense to you and helps to answer your questions some what. Regards, Ronni 13-inch MacBook Air (April 2014) 1.7GHz Dual-Core Intel Core i7, Turbo Boost to 3.3GHz 8GB 1600MHz LPDDR3 SDRAM 512GB PCIe-based Flash Storage macOS Sierra 10.12.3 > On 8 Feb 2017, at 3:11 pm, Neil Houghton <n...@possumology.com> wrote: > > Hi all, > > As a result of changing internet plan, I scored a new modem. It creates 2 > wireless networks - one on 2.4GHz and one on 5GHz. > > > Both appear to work just fine so I used the option click on the wireless > menu-bar icon to see what differences were apparent. Report as follows: > > 2.4GHz network: > RSSI: -68 > Transmit rate: 117 > MCS Index: 14 > > > 5GHz network: > RSSI: -70 > Transmit rate: 162 > MCS Index: 12 > > > I'm not sure what that all means ;o) > > I understand transmit rate - which would seem to suggest that the 5GHZ at > 162 is performing slightly better than the 2.4GHz at 117 ?? > > > Are the other figure significant? > Are there other factors to consider when choosing which network to use? > > > > TIA > > > > Cheers > > > > Neil > -- > Neil R. Houghton > Albany, Western Australia > Tel: +61 8 9841 6063 > Email: n...@possumology.com
-- The WA Macintosh User Group Mailing List -- Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> Settings & Unsubscribe - <http://lists.wamug.org.au/listinfo/wamug.org.au-wamug>
