Pyra mobile broadband performance


CommanderB

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Mar 1, 2014
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Hi!

Finally my long-awaited mobile edition Pyra arrived and I am totally excited about the device.
However, I am experiencing heavy mobile radio reception issues:
The reception is extremely location-dependent: On one side of my work-desk I get about 60% RSSI and LTE reception and on the other side of the desk (70cm away) I get no mobile connection at all. This looks to me like an antenna issue.
I also tested the reception outside, to exclude some influence from steal beams, or interferences, but the location-dependence effect is the same, even on the parallel street.
In general the reception at my place is really good, I usually get about 90%-100% reception rate and ~40 Mbps with both my Android phone and my Pinephone using the same SIM card. (Telefonica-Germany)
The performance is even at the "best" locations kind of bad, as I get at most a download rate of 50-100kbps.

I wonder, whether this might be a general problem, or only a single faulty device. How are your Pyras performing?

I also noticed something different: When I boot my device, the modem rarely disappears and is not even listed via lsusb. I wonder if this is a bug related to the GPIO modem switch configuration?
 
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TrashyMG

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I also noticed something different: When I boot my device, the modem rarely disappears and is not even listed via lsusb. I wonder if this is a bug related to the GPIO modem switch configuration?

The only Cellular provider in my are doesn't support GSM and from what I gather doesn't encourage third party devices, but I bought the Cellular version to get GPS, long story short I also notice the device disappears on occasion .

I mentioned this to aTc and it suddenly appears, so perhaps the solution is to just start complaining to aTc to fix it.
 
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aTc

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There are still some weird things happening with the modem sometimes. Like it dissapearing for no reason at all, or it only showing up minutes after booting.

Mine seems to work pretty well though, i think it reached 200mbit easily when doing a speedtest (went through my 2gb prepaid test card in seconds). Although i have pretty much line of sight to the transmitter here.
Reception does seem a bit low at 60%
I have only really tried it with the pyra on my desk, I'll see how it behaves when using it at a few different locations.
 

Silent-Hunter

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On the other hand, I actually care more about how well phone calls work. But given that those may be VoLTE only eventually, it's still not great that data doesn't work well.
 

aTc

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Voice calls are something I haven't really tried yet, it requires some messing about with audio devices, and those drivers are half broken.
Theoretically it should work, but currently there's no easy method in place to get it to work, you'd have to reroute input/output audio devices manually.
I haven't really found any good desktop based phone software yet, most of the phone stuff out there are solutions that take over your entire device.

SMS works fine though :)
 

CommanderB

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Hmm, 60% in LOS is really bad. I will try to locate my nearest cell tower via CID code and test the Pyra's reception close to it.
The Librem5 is using the same modem as Pyra and they had radio issues in their first batch, too:

A reddit post criticises the chosen modem, but I don't know how valid the arguments are:

Maybe the antenna matching is not optimal in the Pyra?

Btw. how is it possible to obtain the modem's firmware and to flash it?
 

docbroke

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Voice calls are something I haven't really tried yet, it requires some messing about with audio devices, and those drivers are half broken.
Theoretically it should work, but currently there's no easy method in place to get it to work, you'd have to reroute input/output audio devices manually.
I haven't really found any good desktop based phone software yet, most of the phone stuff out there are solutions that take over your entire device.

SMS works fine though :)
Have looked at https://wiki.mobian-project.org/doku.php?id=calls
 

pyrat

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Sorry to hear this. I can understand it is sad to some users but it doesn't seem easy to fix.
I, like @TrashyMG picked the modem also mostly to get GPS. I don't like to be reachable always and everywhere.
If the modem is good enough for emergency calls (or emergency SMS, or emergency emails or whatever works out there) I should be fine. If not, it's OK too, I don't have a mobile phone now.
On the other hand I'm happy that the modem has been chosen for free firmware, and I didn't know that it was the same mobile as in Librem5. It's hopefully a surprising oportunity for sinergies.
@CommanderB, That reddit post was interesting to me. Sounds credible (but I couldn't tell) and I didn't know it.
 

CommanderB

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I think that the problem is fixable, but we need more investigations. Due to countless carrier/bands combinations there might be some incompatibilities and @EvilDragon is not able to test all of these. So, if we could run some tests using speedtest-cli and post our results including the frequency/carrier here, it might already help to locate the root cause of the problem.
 

Phlyra

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I will try to locate my nearest cell tower via CID code and test the Pyra's reception close to it.
Is this something that’s possible to do in Europe? Is there a simple way of looking it up on one’s phone? I’d like to find out the same thing, although for a different reason.
 

hns

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Hmm, 60% in LOS is really bad. I will try to locate my nearest cell tower via CID code and test the Pyra's reception close to it.
The Librem5 is using the same modem as Pyra and they had radio issues in their first batch, too:

A reddit post criticises the chosen modem, but I don't know how valid the arguments are:

Maybe the antenna matching is not optimal in the Pyra?

Btw. how is it possible to obtain the modem's firmware and to flash it?
Well, the cited article is indeed misleading. The PLS8 module is NOT a stripped down IOT modem neglecting features needed for portable devices but a full mobile device. It also contains everything for power-management on the modem side. It reduces power conumption while waiting for something to happen (SMS arrival, incoming call) to some milli-Amperes. If there are power-management issues they are outside of the modem. The author seems to forget that these modems are not only used in vending machines or car entertainment systems but portable devices like the scanners and handhelds used by parcel delivery services. So the modem firmware has definitively been designed with power management in mind.
And to be honest, the assumption that these modems do not do handoff between base station cells is pure nonsense. It is a certificaton requirement of the modem that it works as defined by the 2G/3G/4G standards. Maybe the author should have looked in the specific data sheet...
What I also don't understand is his discussion about Purism engineers developing firmware for the modem. The modem comes with already flashed and approved firmware. It needs as much firmware as an stick type modem plugged into some USB slot. Of course it needs some kernel driver to turn in on and off and some user-space software to make use of the commands. But that is not firmware and does not depend on hardware.
So there is no need for a "newer" or "better" modem firmware to flash. Of course the modem manufacturer likely has different firmware but they can't give that away without violating certification requirements (remember that this is a RF device which connects to a public network and every hardware design and firmware version must go through CE and FCC to prove that it does not harm other users).
Reception quality depends on a lot of factors. One is that the antenna in the Pyra could not be placed where it would have been optimal (maybe in the top of the display lid but you may remember the WiFi cable issues of the Pandora). It had to be placed under the keyboard in the lower right corner and is even covered a little by the keyboard scan matrix maeanders. So it is necessarily a compromise. A second compromise we had to make is that it is recommended to use antenna diversity, i.e. a second antenna in as much distance as possible. Well, if you look at the photos of the PCB there is no place in any distance. This means that reception quality depends on the orientation of the device. Like the GPS receiver (which has an antenna looking upwards from the right edge of the keyboard) is also orientation dependent and has weaker reception if you close the lid.
So there is not much to improve (unless we would design a new main board based on all experiences gained in the past years).
 

CommanderB

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Thanks a lot for the interesting detailed explanation! What I love about the boards is that you can always learn technical details from the experts here.

Speaking hypothetically, would it have been possible to place two antennas in the sides of the bottom part of the case and connect these using connector cables to the motherboard?
 

elw3

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My guess is it currently uses the wrong band or has power save features enabled to MAX.
I finally found the chapter about them in the manual.
According to that you can indeed select how much power the antenna pumps into a specific frequency with just issuing some simple terminal commands.
Too bad i cannot check that out atm.
 

CommanderB

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Mar 1, 2014
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Ah, which chapter is it?

I made some further tests: With Telefonica, I can get a connection inside at some locations. It's definitely much more location dependent than orientation dependent. Inside, I get about 1 Mbps at most. Outside I often (But not always!) get a reliable connection, especially if I'm outside in a field with no structures nearby and antenna LOS. Then I receive around 5 Mbps. For reference, I get ~25 Mbps with my Pinephone when I use the same SIM card and stand in the same place.
Using the Vodafone SIM card I am not able to get any connection with the Pyra at all, but the Vodafone reception is notoriously bad in my hometown. Even my S10 is barely reaching 10% RSSI.
 
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