Cell phone minimum Rx signal level

[Jester]

Not sure what I can trust from Google search on this topic, has anyone done some real world testing of minimum signal level required for SMS data transfer?

I tried using MD Faraday bag tester application on an Android.

Normal signal level at test location -112dbm

Inside Faraday bag  -127dbm
Inside one layer of foil -127dbm
Inside two layers of foil -127dbm
Inside two layers of foil and Faraday bag -127dbm

So I'm speculating the software has a -127dbm limit

Obviously varies from phone to phone, but roughly where is the cut-off point for no data?

Thanks in advance to all that respond.

[ahbushnell]

I would bet its 127dbm cutoff.

Sent from my SM-G930V using Tapatalk

[DaJMasta]

Do you know what radio chipset the phone in question uses?  It's probably got a rated minimum for connection maintenance, then you just need to figure out what the gain of the antenna is.

If not a software limit, it could be the noise floor of the device making the measurement.  I think you need a more granular attenuation amount between -112 and -127 so you can see where the number stops changing.  You could put a box over the phone and then just start heaping stuff on it when the test is run 

[amyk]

127 is 2^7-1, probably not a coincidence that it's the minimum measurable level.

[Sceadwian]

Generic google answer is -110 is about minimum for a crappy connection. But keep in mind SMS is inherently unreliable to begin with so if you have a connection THAT bad text messages can get lost for quiet a while if not left undelivered.

If you need to be sure an SMS gets through to a location reliably -112 is not going to cut it.