Struggling to reconcile rsrp with "Good - Fair - Poor etc" indications

[WirelessBoy]

Using the Three app to optimise the position of my ZTE router I get some odd readings as I move my router about:
-81 = Excellent
-93 = Poor
-103 = Good
-106 = Fair

This doesn't make sense. If -81 is excellent and -103 is good, then why is -93 poor???

According to my Google searches RSRP Signal Strength Guidelines (in dBm) RSRP values typically range from approximately -44 dBm (very strong) to -140 dBm (very weak). 

RSRP (dBm) Signal StrengthDescription\(\ge \)

-80 dBmExcellentStrong signal with maximum data speeds

.-80 dBm to -90 dBmGoodStrong signal with reliable data speeds.

-90 dBm to -100 dBmFair/PoorReliable data speeds may be attained, but performance may drop.\(<\) -100 dBmPoorMarginal data with drop-outs is possible; connection loss is likely.

Can someone explain why my readings don't tally with the Three Apps assessment of signal strength?

I noticed that the number of bars on the strength bar icon seem to follow the descriptions - not the RSRP readings.

[clivejo]

Probably not Reference Signal Received Power(RSRP) readings being used to determine how "good" the signal is.  There are other metrics used to find out how good quality the signal is.  Like SNR, RSRQ, RSSI, CQI.  For example, Threes Band 20 travels well and tends to measure a good RSRP, but is often so noisy/congested that the signal quality is very poor.

[WirelessBoy]

Thanks for taking the trouble to reply. I'm impressed that there are so many different measures but as none of them is available in the app they don't help me find the best place for the router. So why bother teling me what the rsrp is then? I might just as well use the good etc ratings. I suppose I could measure the download speeds?? 

[clivejo]

RSRP is the most basic of measures, think of it like how loud you can hear a voice.  Then imagine trying to pick out that one particular voice in a crowd of voices all talking at once, this is noise.  If the noise is too much, then the communication gets harder and speeds slow down.  Therefore, the loudness is not the best indicator for the "signal".

The router would/should give you more detailed readings.  Regarding the Three App, there are a lot of things I don't know why Three have decided to take their approach on.  Personally, I can't stand when they refer to the router as a wifi box or "hub" and putting out messaging that customers can now use vodafone network.  It's not even dumbing it down, it's out right misinformation!

I believe that ZTE have a mobile app, have you tried it?  Maybe Three have it locked down to make it useless to advanced users.

[WirelessBoy · Accepted solution]

Thank you for the useful advice. I've got the router in the best place for me - which is a compromise - but the performance is fine for my needs. I'm just relying on the router's assessment which is "good" & three bars in the indicator.

Having recently moved to Three from Vodafone I'm pleased with the change. Better performance - reliability good so far - and cheaper.

[clivejo]

No problem.  I live in a rural area and tested out lots of different routers and even directional antennae pointing directly at the masts.  If you have any questions feel free to ask.