MT700: Possibilities to improve LTE Signal

krabbenhoernchen

Hi,
I have an MT700 and so far I’m quite happy with it. Thanks for the great product!

Currently, there is one thing I’d like to have improved. The mobile network signal reception seems weak compared to other devices. Despite having good coverage of both LTE CAT M1 and NB-IoT at my location, the MT700 has difficulties to connect when indoor.

Is there anything I can do to improve the signal reception, e.g. by soldering an additional antenna to the PCB or anything else?

Best
Krabbenhoernchen

Garin

@krabbenhoernchen Generally, if the CAT M1 network has coverage, it will be fine even indoors, although GPS is unavailable indoors. If possible you can share your config info, we can check what happened.

krabbenhoernchen

Hi @Garin, thanks for your reply!

Here is my config:

<CFG>:NET:TCP
GU:MT700,0000
UP:0000
SRV:DM,<my_traccar_server>,5030
APN:iotsim.melita.io,,
NWM:3,1,3
M1:ANY
NB1:ANY
GSM:ANY
EDRX:0,4,0010
<CFG>:ID:<redacted>
DBG:ON
HBC:5m
DUR:2m
RWT:60s
LEP:OFF
LTP:ON
CSN:OFF
LBS:0
AGPS:OFF
XTRA:ON
TZ:0
ANG:0,0,0
GSEN:70,70,2,187
<CFG>:CCID:<redacted>
SAVE:1,0,10m
SOC:NORMAL
PRIOR:GNSS
MODE:0,60s,1h,1,0
<CFG>:ISD:18/04/24
MDL:MT700
SV:V2.1.0.4
HV:V2.0.1
MV:BG96MAR04A05M1G_01.002.01.002
LIC:OK
AU:Darren@Mictrack
IN:linkedin.com/in/imdarren

I already played around a bit with the NWM settings. I tried:

NWM,3,1,3 (NB1 only, prefer NB1)
NWM,3,2,2 (NB1 & M1, prefer M1)
NWM,3,2,0 (NB1 & M1, automatic)
NWM,3,0,0 (M1 only, automatic)

But none of these configurations helped to get a successful connection in my garage.

I’m currently testing by keeping the MT700 on a static location on my desk.
Especially with the current setting (NWM,3,1,3), I observe that sometimes the device fails to connect for a complete wakeup period (₁₀ minutes).
Sometimes, it connects instantly.

However, I’d like to deploy the device in my garage and get a notification instantly after the device has moved. In my garage, the MT700 did not manage to connect at all. It just prints <Trace>:Network login erro
At the same time and location, my mobile phone gets a (weak) signal via LTE, so I think there should be enough signal for NB-IoT or M1.

Do you know if the MT700 automatically try another Coverage Enhancement Level when it fails to connect? Or do I need to enable this in the configuration?

Any other ideas how I could improve the signal reception?

Edit: Here, some debug reports of the Signal Quality (CSQ)

Desk (inside): 12-14
Outside: 24

Best,
krabbenhoernchen

Garin

Hi @Kkrabbenhoernchen Thanks for sharing.

For Europe, we suggest locking to CAT M1 with 2G fallback. This way, when the CAT M1 network is unavailable, it will automatically switch to the 2G. We found the CAT M1 and NB-IoT network is weak or unavailable in some regions.

Also the CAT M1 network is different from the mobile 4G network, meaning that even if the mobile 4G network is good, the CAT M1 or NB-IoT might not be.

Another option is to try locking to GSM only (NWM,1,2,1)to see if it works in your garage.

CSQ is a very important parameter. From your log, a CSQ value of 12-14 is weak, while a value of 24 is good.

Generally, when the device is in the garage, the CAT M1 & NB-IoT signal is weak or unavailable.

krabbenhoernchen

Hi @Garin,

Locking to GSM doesn’t work indoor at all. Only outdoors.

Do you have any suggestion regarding modifying the antenna to improve signal reception?

Garin

Hi @Kkrabbenhoernchen
Most of the time, the signal in the garage is not good, leading to the device failing to report data to the server. Sometimes, even if it can find a weak signal in the garage, this does not mean that data transmission (networking) is also normal.

Currently, the 4G antenna is already optimally designed with the current hardware, and no changes are planned.