Cell phone information needed for Arches NP, Utah

[alanmalk]

We are going to camp host in Arches NP again this fall. But this time around I feel the need to have actual cell phone service in my trailer, so to not have to run up the hill to the top of the campground. I anticipate solving that problem with a cellphone amplifier.

As most of you know I prefer to do it the hard way and spend as little $$$ as possible. To that end I plan to make some of the equipment myself. However, I lack one important bit of information.

The frequency of the signal is rather critical if making a radio system at minimum cost. So, I am asking anyone with an AT&T plan, planning to camp in the Devils Garden CG, to put their phone into "field test mode" (the term Apple-iPhone uses), and discover the band and/or frequency that the phone is using.

The specifics of Devils Garden and AT&T are important. There are likely a lot of places in Arches that get service, and quite a number of providers, but they won't be helpful for my purposes. I actually have the required information for Verizon thanks to a friend in Moab (and it seems most folks in Moab prefer Verizon). But as mentioned, it is not very useful for building an antenna.

So, anyone with an AT&T plan, in Devils Garden, that wants to play with their phone - and Androids do this also, I just don't know what they call it - if you find something like B-12, B-16, B-66 (the bands) or numbers like 740, 1800, 2200 or similar frequencies, please post it here.


Many thanks!

[Centex]

Alan, I'll be at Devils Garden Campground site 19, March 29 - April 5. I'm on AT&T with an iPhone 12 mini. Per experience shared by David Murphy specific to this site I do not anticipate having cell service, at least not at the trailer.

I'll be glad to run whatever tests you would like, from site 19 or other locations you describe in the park, but I need guidance on how to get anything beyond 'counting bars' on the home screen.

Please post here or drop me a PM or email explaining how to get the info you would like on my iPhone, I'd like to help if I can.

[alanmalk]

Originally Posted by Centex

Alan, I'll be at Devils Garden Campground site 19, March 29 - April 5. I'm on AT&T with an iPhone 12 mini. Per experience shared by David Murphy specific to this site I do not anticipate having cell service, at least not at the trailer.

I'll be glad to run whatever tests you would like, from site 19 or other locations you describe in the park, but I need guidance on how to get anything beyond 'counting bars' on the home screen.

Please post here or drop me a PM or email explaining how to get the info you would like on my iPhone, I'd like to help if I can.

Hey Alan,
Thanks for the offer of help! I'll give the explanation here just in case others are wondering what sort of techo-magic we are doing.

These instructions are for an iPhone - I know there is something similar on Android but don't have one to play with.

Start by doing a manual dial on the keypad: *3001#12345#*
including the * and #. Your phone should show a screen with only text at this point. (I'll upload lots of photos but they will probably be out of order.)

Click the right arrow on the "RAT / Serving Cell Info. This will have numbers, hopefully starting with PLMN = 310 410. In the Android world they will be labeled MCC & MNC which I believe is the more common label. But the meaning of 310 410 is "AT&T Mobility". Bingo - good to go. But possibly you will get a different AT&T PLMN depending on your plan.

As an example only, Verizon phones will see 311 480 at the campground. But I'm a cut-rate AT&T guy, if I can hold out anyway.

Another interesting screen - which I don't absolutely need is the "RsrpRsrqSinr" which shows the received power in -dBm. It is -105 at my home location - decidedly poor at 2 bars but mostly usable. It will be weaker in the Devils Garden - goes without saying.

Examples of these screens are also attached. Also some screen shots of various bits of converted data.

My suggestion is to try this experiment around sites 21-25 for the strongest signal. If you can see the LaSal Mountains to the South then you ought to be good to go.

Enjoy Arches and have fun!


Adding a bit more: My hope is that you can provide the "Band Info" from the "RAT" screen. You can see the 12 (at my home). In the campground it might be 12, 14, 66 or perhaps another 2 digit number that I wasn't expecting. Lower down on the screen is EARFCN #. That will also be very useful after I plug it into a converter to give me frequencies. Once I have that data I can start hammering and sawing.

[Centex]

Originally Posted by alanmalk

These instructions are for an iPhone - I know there is something similar on Android but don't have one to play with.

Start by doing a manual dial on the keypad: *3001#12345#*
.....

OK, so here's all of the screens I get when I test this at my rural home using my usual external antenna and signal booster. For this test I turned off my hotspot, so this is straight cell reception data (not through the hotspot > wi-fi > iPhone).

Not the same screens as your example, but maybe that varies by phone or location?

I'll do this from Arches, capture the screens for posting. If you've any other suggestions / guidance for getting the data you seek, I'm all ears!

[alanmalk]

Originally Posted by Centex

OK, so here's all of the screens I get when I test this at my rural home using my usual external antenna and signal booster. For this test I turned off my hotspot, so this is straight cell reception data (not through the hotspot > wi-fi > iPhone).

Not the same screens as your example, but maybe that varies by phone or location?

I'll do this from Arches, capture the screens for posting. If you've any other suggestions / guidance for getting the data you seek, I'm all ears!

Perfect for my use! You have confirmed AT&T (PLMN of 310 410) and the frequency up and down using a EARFCN (Down Link) converter (free, I just Google for one). EARFCN of 1075 = 1897 & 1977 MHz.

And you are correct. The screens will vary with phone and internal software and location. I see you have an rsrp (received signal power) of -99 dBm. Rather weak, which is the reason I assume you have a booster. That is a number I expect to see in Arches, too. Weak or worse! And most significantly, the EARFCN in Arches will be different, perhaps by a significant amount. I wouldn't be surprised to see frequencies around 750 MHz. (But on the other hand, I was very surprised by the Verizon signal measured by my Moab friend. Could have been an expensive mistake for me.)

[Centex]

Originally Posted by alanmalk

Perfect for my use!

OK, I'll print this thread to carry for guidance when I don't have internet at Arches.

I may not compile the screenshots and post the findings until I'm back home around April 22 +/-, still should be timely for your interests.