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6 votes
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Why do bluetooth headsets get interference (choppy sound quality) outdoors?

As you might have already realized there is a good reason that some of Bluetooth headset are inexpensive. Poor design. High quality, well designed Bluetooth headset tend to be expensive. Also not all ...
Mahendra Gunawardena's user avatar
6 votes

How are three satellites sufficient to find a unique point in GPS? What happens in case of an overlap?

You can't ignore the difference between 2D and 3D in this situation. To a first approximation, all GPS satellites are located on the surface of a sphere. There is no way that any three points on a ...
Dave Tweed's user avatar
  • 6,894
5 votes
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How to determine signal strength verses distance for LTE base stations?

For a LTE base station is it possible to determine the relationship between the signal strength and distance? Ideally yes. Practically, probably not very reliably. Given the following pieces of ...
Andrew W.'s user avatar
  • 196
4 votes

How can I find the emission power of a WiFi mobile phone antenna?

Typically, the max is 100mW (20dBm). You can refer to an example wifi chip datasheet (This one is used in many mobile phones with Snapdragon processor) - https://developer.qualcomm.com/download/sd410/...
Bharath Patil's user avatar
4 votes

What is the difference between Bluetooth Low Energy and Bluetooth BR/EDR in Park mode?

There are many factors that make BLE low power, and I have attempted to address as many of them as possible. In order to better understand the power consumption differences between Bluetooth classic ...
Mahendra Gunawardena's user avatar
4 votes
Accepted

How can I make a GPS traceable microchip?

Firstly you seem to be under the common misunderstanding that the GPS satellites somehow calculate where a GPS receiver is. They don't. The satellites are transmit only systems (ignoring the command ...
Andrew's user avatar
  • 766
3 votes
Accepted

Why only the spectrum range of radio waves can be reflected from atmospheric layers while higher ranges (Infrared-Visible Light-Ultraviolet) can't?

Different materials reflect, absorb, and scatter different wavelengths of light. The ionized layer at the edge of earth's atmosphere happens to reflect a certain range of wavelength while ...
Olin Lathrop's user avatar
  • 11.4k
3 votes

How are three satellites sufficient to find a unique point in GPS? What happens in case of an overlap?

how are three satellites sufficient to find a unique point in gps? They are not. It takes four satellites minimum. GPS needs to solve for the point in four dimensions, X, Y, Z and time. Four ...
Olin Lathrop's user avatar
  • 11.4k
3 votes

How can one determine the LTE base station providing service to a mobile device?

You can see this information if you enter "field test mode". Google that for device specific instructions. It should show you the name or serial number of the base station you are connected to, but I'...
Andrew W.'s user avatar
  • 196
3 votes

How can I find the emission power of a WiFi mobile phone antenna?

There is a list of some widely used devices and their transmit power (and many other properties) in an easily digestible table: https://clients.mikealbano.com/ The most smartphones seem to be just ...
AdamKalisz's user avatar
3 votes

Interference between direct signal and reflected signal

Wifi uses Orthogonal frequency-division multiplexing (OFDM). OFDM is resilient to delay spreading which essentially is multipath RF signals or signal bouncing off walls per your question. Here is ...
Mahendra Gunawardena's user avatar
3 votes
Accepted

Wireless communication modules transmitting through body

The reason you can't find many modules around 100 MHz is that it's not an open frequency and you generally need a permit to transmit at those frequencies. Another reason is that you will face some ...
Jollerprutt's user avatar
2 votes
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Why is Li-Fi faster than regular wifi?

The wave propagation speed is only relevant when you start approaching the theoretical limit of that type of wave's ability to transmit information. For an analogy, consider people having a ...
Air's user avatar
  • 3,211
2 votes

A 40MHz oscillator in usb wifi adapter

Generally when you need to scale up a clock you use a PLL (Phase lock loop). A very crude explanation is that you have a voltage controlled oscillator at roughly the required frequency. You divide ...
Andrew's user avatar
  • 766
2 votes
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Why GPS receivers are more sensitive than GSM or WiFi receivers?

There are a few factors at play. Firstly as Olin indicated the signal bandwidth and data rates are different. It is a fundamental rule of information theory that the maximum amount of data you can ...
Andrew's user avatar
  • 766
2 votes

Most practical way to wirelessly transmit a single bit of information?

To be totally honest there is really only one technology you should be looking for. Infrared, all you need is a light transistor and a infrared led, thats it. Cheap as hell, well known, and robust ...
joojaa's user avatar
  • 3,577
2 votes

Tethered Balloons vs Towers for Wireless Communication

They would be a great hazard to air traffic; The umbilical would be essentially invisible to passing aircraft. In spite of regulations not to fly here or there.
blacksmith37's user avatar
  • 6,144
2 votes
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Can wider range (i.e. 600-700 MHz) antenna replace lower range (650-700 MHz) antenna?

The operational frequency operational range of the proposed antenna is within the frequency range of the old antenna. It should not be an issue from frequency standpoint. If the gains are similar ...
Mahendra Gunawardena's user avatar
2 votes

Bandwidth vs Capacity

Your understanding is correct. Here is an alternate definition from Wikipedia - Bandwidth Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. ...
Mahendra Gunawardena's user avatar
2 votes

Why do we always use 3.8 x 10^(-3) value as Forward Error Correction (FEC) threshold?

I found this. Which states: For example, for 7% overhead HD-FEC with a NCG of 9.19 dB at a corrected BER of 10−15, the pre-FEC BER should be lower than $3.8 × 10^{−3}$ [4], which is regarded as ‘...
DKNguyen's user avatar
  • 5,641
1 vote
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Most practical way to wirelessly transmit a single bit of information?

Few of the technologies that fit well are Bluetooth Low Energy and Thread. Both of them operate in the 2.4 GHZ ISM band. Also you might want take a look at Zigbee. These all offer basic level of ...
Mahendra Gunawardena's user avatar
1 vote
Accepted

Why does India have more than 1 MCC (Mobile Country Code)?

The Mobile Network Code (MNC) is either a two digit ("European" standard) or three digit ("North American" standard) identifier, with in the Mobile Country Code (MCC). According to https://en....
alephzero's user avatar
  • 12.5k
1 vote

How to decode radio thermometer / hygrometer bytes to floats?

This is not a full answer but I can't comment yet due to too less reputation, sorry. I+J seems to have a strong correlation with the temperature. I did a scatter plot of I+J vs. Temp and I can see at ...
JLo's user avatar
  • 163
1 vote
Accepted

What criteria to focus on when selecting a BLE module?

Looking at if the device supports BLE 4.0, 4.1, 4.2 or 5.0 is a good start. Not all BLE modules are 5.0 capable. What type is distance range might be a parameter to consider some BLE module have line ...
Mahendra Gunawardena's user avatar
1 vote

dB/s/Hz in spectrum efficiency

As with any physical equation, the units of a constant, in this case "spectrum efficiency," are chosen so that the final result is in the units desired. So, if you're going for an answer in dB, then ...
Carl Witthoft's user avatar
1 vote

Making my microcontroller transmit audio to any bluetooth headphones/speakers

There are Bluetooth adapters available which will hook into audio system via 3mm jack or optical jack and broadcast the music to your headset. However if you want to receive the music into your phone,...
kamran's user avatar
  • 22.5k
1 vote
Accepted

Can you detect the operation of a wireless radio (or other wavelength) receiver?

many radio receivers contain a circuit called an IF oscillator. the output of this oscillator is added to the radio frequency signal that the radio is receiving to downconvert the incoming high ...
niels nielsen's user avatar
1 vote

How can I make a GPS traceable microchip?

I second Pisda's point, but lets get hypothetical here: RFID and related chip technology already uses a chip that is powered by the radio signal send to it. So in 'theory' you could use that to ...
RC NL's user avatar
  • 11
1 vote

Why not only GSM (3G/4G/..)? Why do we need Bluetooth, Wifi,etc...?

Several reasons but mostly bandwidth and speed. It makes sense to keep all communication channels as short and local as possible. This reduces likelihood of interference, channel contention and cost. ...
Transistor's user avatar
  • 10.9k

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