Questions tagged [cellular]

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67 views

How to add a 4g / 5g feature on a single board computer design with a cheap price?

Let's assume, I am planning do design my own single board computer just as a hobby regardless of whether it is wise or not. Searching online has made me so confused. In general, I see two options: ...
2
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1answer
110 views

Accidentally connected a GPS antenna to a cellular connector and a cellular antenna to a GPS port. What can go wrong? [closed]

I have two ultra small/sub-miniature coaxial connectors on my circuit board - one for a cellular (4G) antenna and one for a GPS antenna. I accidentally connected the cellular antenna to the GPS ...
0
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0answers
16 views

Effective radiated power of small cell site dependent on number cellphone users?

Is it correct that during the day, when it's assumed more cellphones will be accessing a small cell site, the effective radiated power could be at its maximum (max ERP calculated at 85.4 watts) ...
0
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2answers
60 views

IoT Certification Legality

I am developing an IoT product for a company. The product runs off of two alkaline batteries at a max of 3.2V. It is fully enclosed in a solid plastic case, with small panel openings for a switch and ...
1
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0answers
44 views

Smartwatch GSM antenna design

Which antenna design is the most applicable to a 2G smartwatch (about 40x40mm)? I have tried some sketchy ultra-short (about λ/8) whip antennas, but due to a fairly small ground plane and unfortunate ...
1
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1answer
52 views

Is NB-IoT roaming possible?

I found a comment on a blog post stating that NB-IoT doesn't support roaming: nbiot do not support roaming (you must have sim from the operator that have the infrastructure). nbiot also lacks ...
0
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1answer
58 views

Shannon - Hartley Theorem

Let's consider the Shannon - Hartley formula for the channel capacity \$C\$: $$C = B \log_2 (1 + S/N)$$ I have two doubts about it: 1) is it correct for TDMA, FDMA, or CDMA? And why? 2) Can a ...
0
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2answers
42 views

Echo in voice to the caller while receiver with headphone hving wire replace [closed]

Hi I just replaced the old wire in my headphone with new one.But while using headphone the caller hears the voices with his own echo but while me having headphone on has no issue of echo can speaks ...
0
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1answer
33 views

Telit cellular module pins connection

I have the UE910 cellular module from Telit. I have manufactured a PCB containing the module but it's not working (power is reaching it but serial program not communicating with the tx and rx pins). I ...
0
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2answers
70 views

coplanar waveguide vs microstrip for gnss and cellular?

coplanar waveguide vs microstrip for gnss and cellular? I read on internet microstrip is better for signals <30Ghz but some gps manufacturer (Delorme) said that coplanar is most efficient so it's ...
1
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0answers
49 views

Intel Compute Stick & USB 4G Device

Id like to create a powerful IoT Edge device that has cellular capability (Wifi is undesirable). Right now the intel compute stick/neural stick almost fits the bill except that it does not have 4G ...
0
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0answers
30 views

NB-IoT/CAT-M1: Llimitation to the actively connected devices

For the new Cellular IoT technologies NB-IoT and CAT-M1, is there a limitation to the number of modems that can be connected to the base station at one time? I tried searching for this but I couldn't ...
1
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2answers
55 views

Testing the RF properties of an enclosure

I need to measure RF (cellular) blocking properties of an enclosure. Is there an off-the-shelf set of tools for doing this? I'm assuming a MHz signal generator and an oscilloscope with an antenna ...
0
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2answers
43 views

Cellular chip antenna feedline width?

I have a chip cellular antenna from Pulse W3544B. In the datasheet it is said to make the transmission line 1.34 mm thick which I feel is too huge and also I wanted to make a strip line for impedance ...
0
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2answers
66 views

Can I use MCU's internal oscillator when communicating with GPS and cellular modules?

Can I use MCU's internal oscillator when communicating with GPS and cellular modules? I want to avoid connecting external crystals for the MCU since they generate noise, extra components, extra costs, ...
0
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0answers
58 views

Cellular towers in rectangular grid

Not that far from where I live there are 6 towers that appear to be for cellular purposes in a perfect grid. You can see them in the picture I took from google maps. In the center of the road are ...
1
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1answer
267 views

Transmitter and Receiver antennas in mobile phones

I understand that in old cellular systems where FDD were employed, we used to have same antenna at the mobile phone (User equipment) for transmission and reception.Moreover, a duplexer was used to ...
-1
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3answers
245 views

Does the phone transmit waves? [closed]

In a cellular connection, How much is power density (in W/m2 or mW/cm2) of the RF energy from the phone to the tower? If not possible in above units then can I know in dbm ? My phone has: Head SAR: ...
0
votes
1answer
30 views

Bridging 3G/LTE from cellphone to IOT device

I have an IOT device that needs to function as an access point, even without close by wifi signals, and then publish a wifi network. I know that I can achieve this with a 3G/LTE/GSM module but given ...
-2
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1answer
151 views

How does cellphone idle time work?

Imagine a basic cell phone which operates in only 2G network and able to provide voice call & SMS service. Does this cell phone transmit any data to BTS in idle time (that is when the cell phone ...
3
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2answers
293 views

Top Ground Copper pour in PCB having three RF Sections

I am designing my second RF board (First one had BLE). This board has LoRa Components (SX1257 and SX1301), GPS (MAX-6) and 4G LTE Module (SIM7600). All the components are on top layer (red layer). My ...
5
votes
1answer
799 views

SIM808 registration denied for new SIMs

I have a SIMCom SIM808 2G GSM module on a custom PCB based upon the Adafruit FONA. I got a bunch of 2G SIM cards from Aeris.net. The problem is when I first put the SIM cards in my device, I get "...
1
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1answer
63 views

What is the “minimum” transmit power for uplink cellular transmission

Can anyone help me in finding a good reference for minimum transmits power for uplink cellular transmission? is 0 dBm a good enough power for very low-power transmission in an indoor environment? ...
0
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0answers
25 views

Orientation of eNode antennas

What type of omni-directional antennas is used at an LTE base station, also known as eNode? and What is the orientation of such antennas? and how come the 3GPP path-loss model for such antennas is ...
0
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2answers
65 views

Force cellular modem to transmit at maximum power [duplicate]

I want to force my cellular modem to transmit at maximum power so that I can see if that is the cause of microSD card crashes that I have been experiencing in an embedded application. My modem is a ...
0
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2answers
235 views

SIM808 always returns the same temperature

I have a SIMCom SIM808 module built up on my own breakout board. Whenever I query the temperature I get back the exact same temperature, 24.11 (deg C) despite the actual temperature in the room ...
0
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2answers
68 views

Is this warning about wireless modules interfering with aircraft systems true?

I see the following warning for Sierra wireless (cellular) modems: Do not operate the Sierra Wireless modem in any aircraft, whether the aircraft is on the ground or in flight. In aircraft, the ...
4
votes
1answer
291 views

Arduino Cellular Shield EMC Testing for FCC

I have designed an Arduino shield that uses an FCC pre-certified and PTCRB cellular module and I'm wondering about EMC testing and FCC compliance. However, the main concern here is that I am using a ...
1
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0answers
170 views

PCB vs SMD antenna for 2G cellular IoT device

I am designing an IoT module to read water sensors in an Agricultural field, then send the data through cellular to the cloud. My design uses the SIM800H, a quad band cellular modem, to send and ...
-1
votes
1answer
55 views

Can a 3G usb modem be used as a mini Cellphone Tower [closed]

I am curious to know whether small USB 3G modems could be used as cellular towers, and if you would need special firmware to do it or if it is not possible at all. They can communicate with the tower, ...
13
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6answers
3k views

Simulate bad cell phone reception in the lab

I'm currently developing an internet of things device that utilizes a uBlox SARA-U260 gsm/3G modem. In field testing, we have had significant software/firmware issues due to poor cell phone reception ...