Stuck at Signal strength: 99,99


I just got my Hologram Nova modem yesterday. Model is:
Hologram Nova US 4G LTE Cat-M1 Cellular USB Modem (R410)

I registered my Hologram SIM last night and set up my account. My dashboard looks good, State says “Live”.

I’m using it with a Raspberry Pi 3+. Install was uneventful and most of the hologram commands return data. Exceptions include “operator” which I assume is a reflection of not being able to connect. I can also connect and issue AT commands and get valid responses. I have a solid blue LED but the red LED never turns on.

From other posts the “Signal strength 99,99” is an indicator of no signal. I used a long extension cord and went out into the street in front of my house and still get the “Signal strength 99,99” message.

What should I try next? I’ve read through the posts and tried the solutions there. Should I try a different antennae? Maybe a different SIM card? Could where I am not have coverage (I’m in suburban San Diego and know people use their cell phones here - my AT&T cellphone works, different network).



did you see this thread about Nova issues? I would walk through it especially my response about just waiting 2-3 hours and running AT+COPS=? commands:


Hi, thanks for the suggestion. Yes - I left the system on overnight, kind of hoping I’d be the little kid who comes down the stairs on Xmas morning to find Santa left me good stuff. Nope. :frowning:

Dumb question time: Is this model limited to Verizon? I found the ordering info and Hologram docs confusing. The other Hologram modem says 2G/3G and appears to be only AT&T, since everything I can see says 3G is going away early 2020 I figured that route was a non-starter. Some post referred to T-Mobile and also somewhere I’m recalling seeing AT&T associated with this LTE modem.

I think I’m going to activate another SIM card. I have an extra since I didn’t realize the modem came with one so I bought one a la carte.

Thanks again,


What happens when you run the AT+COPS=? command? what is the output? It should see towers.

No the modem will work on Verizon or AT&T in the US as well as most carriers that have Cat-M1 and are partnered with Hologram. The cell modem itself will pretty much work on any Cat-M1 network in the world, then it depends on Hologram having an agreement with the network. Note Verizon basically has country-wide coverage, their Cat-M1 coverage is basically = to their LTE coverage. So odds are there is a Verizon cat-m1 tower nearby.


I get a string of parameters as shown below…

Welcome to minicom 2.7

Compiled on Apr 22 2017, 09:14:19.
Port /dev/ttyUSB1, 13:59:18

Press CTRL-A Z for help on special keys

+COPS: (1,“310 120”,“310 120”,“310120”,8),(1,“312 530”,“312 530”,“312530”,8),(1)


(not sure why that last OK is bold - really, I wasn’t screaming :slight_smile: )

Activating and using a different Hologram SIM card gets the same thing. I may just take a drive outside of my residential area and see if maybe I can get a signal in a shopping center…


Ok so it looks like there may not be any towers nearby that Hologram has an agreement with (or not through their subsidiaries).

For reference the 2 three digit numbers in those lists are MCC and MNC for Mobile Country Code and Mobile Network Code. checkout: to look them up. Yours are:

310 120 = USA, Sprint Spectrum
312 530 = USA, Sprint Spectrum

Per hologram does have agreements with sprint and it looks like sprint does have LTE Cat-M1 networks as of mid 2018 (

My guess is that although Hologram does support sprint networks maybe sprint doesnt let them on their Cat-M1 networks yet. I think this will require someone from Hologram to follow up.

Do you have Verizon coverage in your area?


Update: sometime late yesterday, something changed. I had left the system running as it had been - steady blue LED but red LED was off. Signal strength was reporting as 99,99. I shifted my attention to work on some other tasks and at some point when I looked back at this system I noticed both the blue and red LEDs were lit. I now get a signal of 21,99 and the operator shows as:

+COPS: (1,“310 410”,“310 410”,“310410”,8),(2,“Verizon Wireless”,“VZW”,“311480”,)

I can send a test message and see it in my Dashboard and can also now connect the network.

Any thoughts on why I would have a couple of days with signal strength showing 99,99 and then now seeming to stay around 21,99?

What about signal strength - is 21,99 a good signal, marginal or what?

I have an omnidirectional antennae for LTE coming today, am hoping I get a more reliable signal with it.

Thanks for the support!


Hi, I believe the second of the two values (21,99) will always be 99. The first value, 21, indicates a reasonably strong signal.

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