RCS--how does it work?

[DonTom]

Every 3 dBm doubles the signal strength.

I would say that differently. Every 3DB increase at a receiver is showing double the power from the transmitter. Double the power is not all that noticeable in signal strength. It's logarithmic, so it takes a rather big increase in power to be all that noticeable.

"DBM" is a logarithmic reference to a milliwatt, not exactly the same as a signal difference in DB. DBM is a power level, such as 0 DBM is one MW. 30 DBM is one watt. 40 DBM is ten watts, 50 DBM is 100 watts, 60DBM is a thousand watts and etc.

Therefore, 63 DBM will be two thousand watts.

3DBM is only .002 watts (or 2 mw).

Six DBM would be .004 watts (or 4mw), etc.



-Don- Redcrest, CA

 

[DonTom]

5 bars can be both too little, or too much information.

I also do not expect an SSI to be all that useful. But when there is NO trace of a signal when one walks around in the area outside in the clear, I would NOT expect it to work for any mode.

I will not go as far as saying it is not possible to work, just extremely unlikely--even for data.

And I do not buy at all that a Verizon tower can detect my signal here in any mode.

-Don- Redcrest, CA

 

[DonTom]

Here is something interresting.

I am trying to log into one of my credit card accounts to pay if off, as I usually do every week.

Capital Bank log in requires me to receive a text message from them with a six-digit number:

I have done this countless times in the past. But I canNOT receive the code here. I cannot summit what I cannot receive.

Not a big problem, I will just have to pay it when I get back home in a week or so. But that they cannot text to the same cell phone I use with my RCS text messages from here could be a clue of how it works. Texting to me is NOT working for non-RCS texting.

-Don- Redcrest, CA

 

[TheBar]

What would be a good reason the shut off RCS?

-Don- Redcrest, CA

To keep it from defaulting to RCS. iMessage still has some advantages tho not as many as in the past. Many will disagree but the fact is most things are easier on an iPhone with way fewer problems. My SIL is the IT manager for the city we live in. The city's platform was Android until 2 years ago when they switched to Apple. Which cut their support calls by 2/3 and eliminated 2 staff positions.

In fact, the blue and green bubble conflict is one of the reasons why some Android users switch to iOS – if their friends and family all have iPhones, iMessage-to-iMessage chats provide a much easier and better messaging experience.

 

[Larry N.]

My phone is currently showing -113 dBm, but texting still works good, whether SMS, MMS, or RCS, with no bars shown.

But often radio technicians make very poor radio operators, IMO! I cannot find any display in my Smartphone for db levels.

As Dutch said, on my Motorola Edge+ I found the reading under About/eSIM Status/Signal Strength: 108 dBM at present, but it was 122 dBm when I first looked, then it changed to 113 dBm, now 108 dBm. It also shows LTE, 5G, Not Roaming, and Mobile network state: disconnected.

In other words it's very weak indeed. BTW, when I turned Mobile Data On (I usually keep it off) it was all the same except the Mobile network state was Connected.

 

[NY_Dutch]

As I sit it reports -97dBm and is showing 3 bars. But being 5G, what band is this for? Or is it aggregation/integration based on some link quality metric or bit error rate? I doubt it's something as first order as the olden daze sampled cathode current in an AGC chain. No question it's there only as a nominal indicator of nearby cell towers for users but I've often wondered how literal it is based on the complexities of CDMA over simultaneous bands that can be octaves apart. Or, reporting just band information targeted to a specific subscriber device and ignoring alternate provider status. 5 bars can be both too little, or too much information.

Mark B.
Albuquerque, NM

There are several apps that will give you additional information about your connection, but I don't know of one that will report everything your asking though. Note with your -97 dBm reading, the signal strength is double what it would be at -100 dBm. 3 bars is ok, but it doesn't tell us what signal strengths the phone software is relating to how many bars. As you said, 5 bars can be too little or too much info. The problem arises when different phone makes/modes use different algorithms to set the bar display. 3 bars on your phone could be a stronger signal than 4 bars on mine.

 

[DonTom]

I found the reading under About/eSIM Status/Signal Strength:

Mine does not seem to show a DBM sig level anywhere.

-Don- Redcrest, CA

 

[DonTom]

I cannot summit what I cannot receive.

Weird. It came in an hour later, while I was sleeping.

Too late to use that one, but I will try it again.

I just tried it again and got their six-digit code in a few seconds. So that one-time delay last night was just a fluke or whatever.


-Don- Redcrest, CA

 

[DonTom]

I found the reading under About/eSIM Status/Signal Strength: 108 dBM at present,

I found it in my portable Hotspot under "About Hotspot"

"SNR:0.0 db"

But in my Smartphone, where I have been using the RCS texting, it shows a lot of info under "System-About phone"' but nothing about db-SNR/dbm receive levels there or anywhere else I can find.

Mark just now sent me a text message which I received here fine.

-Don- Redcrest, CA

 

[DonTom]

Mark K5LXP and I are now texting each other with no problem at all.

-Don- Redcrest, CA

 

[Larry N.]

I found it in my portable Hotspot under "About Hotspot"

"SNR:0.0 db"

That's not signal strength, Don -- it's sig to noise ratio. Do you have a place in settings that gives SIM or eSIM status? That's where Dutch and I found ours (under ABOUT).

 

[DonTom]

it's sig to noise ratio.

So? It is what counts to prove it will NOT work at all.

If you have a very strong sig but in the same level of noise, how well is it going to work?

Notice that RBN uses SNR. That's for a reason; it is the only thing that counts. Higher the number, the better the signal, even in a lot of QRN.

Of course there is a lot less noise on higher frequencies, but that is not the point. There is no reason to NOT use SNR for what counts the most.

73, -Don- AA6GA/6

 

[DonTom]

Do you have a place in settings that gives SIM or eSIM status?

I will double check right now. I cannot find anywhere where SIM or eSIM is mentioned. You can also check, here is the manual for my phone.

But I did find a dropdown screen I never noticed before. "Mobil data off" I have it as well as wi-fi off right now.

And I just now sent you a RCS text message saying so. I assume you received it just fine.

I still can find NO clues of how this is working. Magic?

-Don- Redcresst, CA

 

[DonTom]

I just received an error message! I now have a good clue.

"Message not sent--check your conversation with (505)-903-xxxx"

Now I will turn back on "mobile data" with wifi still off.

It works when either one is turn on, but not when both are turned off.

The only question is what it is using when Wi-Fi is off if it is not the Verizon system for the data.

I assume some other system, as Verizon is just too dead here to work at all for anything, IMAO.

-Don- Redcrest, CA

 

[Larry N.]

So? It is what counts to prove it will NOT work at all.

If you have a very strong sig but in the same level of noise, how well is it going to work?

Certainly SNR is important, but it's a diversion from what Dutch was talking about which was signal strength, so when you said you found the dBm reading I disagreed.

A quick look in your manual didn't find ABOUT under settings, but it's a skimpy manual. Have fun...

 

[NY_Dutch]

I just received an error message! I now have a good clue.

"Message not sent--check your conversation with (505)-903-xxxx"

Now I will turn back on "mobile data" with wifi still off.

It works when either one is turn on, but not when both are turned off.

The only question is what it is using when Wi-Fi is off if it is not the Verizon system for the data.

I assume some other system, as Verizon is just too dead here to work at all for anything, IMAO.

-Don- Redcrest, CA

You might be catching a whiff of a signal from someone in the park using an open cell repeater.

 

[DonTom]

A quick look in your manual didn't find ABOUT under settings, but it's a skimpy manual. Have fun...

Settings-System-About phone-RC545L and then two pages of info.

I just now found it!

I just now discovered some of those items in these two pages can be edited or selected for other menus:

Mobile Network State=Disconnected
Service State=In Service
Signal strength=-80 dbm 60 asu
mobile voice network type=4G
Mobile data network type=IWLAN
Roaming=Not Roaming

Can somebody here explain how I can be "disconnected" but "In Service" at the same time?

And I am -80 dbm on what or whose system?

-Don- Redcrest, CA

 

[DonTom]

This has nothing to do with the texting, but I was just looking at my portable Verizon Hotspot (R500L5).

It says:

Internet Status: Disconnected.
Technology: Unknown bearer.
Network: Verizon.
Signal Strength (RSRP):0dbM

The last part makes no sense as "0 DBM" would be a very strong signal of one milliwatt.

So I looked up "RSRP" to be sure:

"Reference Signal Received Power:

RSRP stands for Reference Signal Received Power and is used to measure 4G LTE networks. The signal strength is measured in RSRP, with the best signal being 0dBm and the weakest or no signal being -110dBm. In LTE, signal strength/quality parameters include RSRP, RSRQ, RSSI, SINR and their meaning. "


The next page:

SNR:0.0db

next page:
Roaming: No
APN:VZWINTERNET


The SNR of 0.0 db looks correct, but not the RSRP of "0dbm".

An obvious big mistake, isn't it? Or am I interrupting something incorrect here?

-Don- Redcrest, CA

 

[DonTom]

I was just thinking (danger!). . . .

As we all should know, when 9-1-1 is called from a cellphone, it makes no difference if your own service is available or not, it uses anything it can find to make the call to greatly improve the odds when there is no received signal indicated. Zero SSI. infinite negative DBM (-110 DBM shown as RSRP) 0 SNR will all be indicated for your own system (Verizon, in my case) saying it does NOT work when it will work just fine for a call to 9-1-1 from here (but not tested by me!!!).

For those who didn't know this, read this:

" The FCC's basic 911 rules require wireless service providers to transmit all 911 calls to a PSAP (Public Safety Answering Point) , regardless of whether the caller subscribes to the provider's service or not."

So I assume even though my RCS texting is all non-emergency BS, that it works a similar way as a PSAP.

I think we can all at least agree that this is a likely possibility as I do know there are two other cell services which work well here. One of them is AT&T, the other is US Cellular according to this RV park info. It goes on to say "Verizon and T-Mobile do not work in our park.".

-Don- Redcrest, CA

 

[NY_Dutch]

I think we can all at least agree that this is a likely possibility as I do know there are two other cell services which work well here. One of them is AT&T, the other is US Cellular according to this RV park info. It goes on to say "Verizon and T-Mobile do not work in our park.".

-Don- Redcrest, CA

If you're in a native US Cellular area, they use thier own ~4,500 towers. Otherwise, they roam on T-Mobile and AT&T towers. RCS rides on a cell signal that's registered with the phone's network provider or a roaming partner as authenticated by the SIM. Oh, and for comparison to US Cellular, Verizon owns or leases space on ~70,000 towers.