64
votes
Why is wired Ethernet losing its speed advantage over wireless?
Wired ethernet is not losing its advantage. There are standards out there for 10Gig Ethernet (802.3ae), 40Gig Ethernet (802.3ba), and 25Gig Ethernet (802.3bq). These are primarily backbone/backhaul ...
- 976
55
votes
Accepted
Why is the bitrate of infrared smaller than the bitrate of WiFi?
The premise is false. Infrared communication can be much higher bandwidth than wifi; just look at modern fiber-optic communications.
It looks like you're really asking why wifi is faster than the ...
- 38.5k
48
votes
Accepted
Does Bluetooth interfere with WiFi?
Yes, WiFi and Bluetooth can disturb each other.
But both are equipped to handle that. A standard that is not capable to handle disturbance and/or interference will simply be unusable under many ...
- 81.4k
37
votes
Accepted
Why are there no WiFi earbuds?
Because wifi is the wrong technology for audio transport.
The highly nondeterministic, large-burst approach to data networking introduces a need for a large buffer. This inherently means high latency ...
- 100k
35
votes
Accepted
How is Wi-Fi throughput so high?
You're correct that the actual bandwidth for a single WiFi stream is rather narrow, ranging between 20 MHz for older specs and 160 MHz for 802.11ax. However, the spectral efficiency of WiFi is often ...
- 20.6k
34
votes
Accepted
Are antennas specified for a certain frequency?
It's not so much that antennas are specified at certain frequencies (they usually are), but that they tend to work best over certain frequency ranges, determined by their physical shape and the ...
- 47.1k
29
votes
Which signals (Wi-Fi, mobile phone, and GPS) can reliably be blocked by aluminum foil?
Tim is absolutely correct. I am an EMC engineer and use aluminum foil on occasion to wrap equipment to prove whether emissions of equipment are from the unit or its power cable (or other cables).
In ...
- 661
28
votes
Why is wired Ethernet losing its speed advantage over wireless?
We see now the MKBHD guy going to some street with a phone and getting over 1Gbps. Surly a reserved and shielded Ethernet channel should give us 1Tbps right?
nope, why should it? Data rate is a ...
- 100k
27
votes
Why does WiFi have a shorter range than LTE?
As with any radio receiver, if it can handle a higher data rate, then it is usually burdened with having a higher RF bandwidth and this inevitably means more received background noise i.e. a wider BW ...
- 473k
24
votes
Does Bluetooth interfere with WiFi?
Wifi uses a listen before transmit system. If the channel is busy, it holds off transmitting. Eventually it gets through. Each channel is fixed. If it tries to use a channel that is busy, from ...
- 73.4k
24
votes
Does living next to an electrified railway cause WiFi outages?
The answer is "Maybe". If you look at trains moving along such lines you often see sparking. This is going to cause RF interference. Additionally, the length of the power line itself might act as an ...
- 14.3k
23
votes
Accepted
How does a Dual-Antenna WiFi router work better in terms of signal strength?
In free space with a nice direct path, it would make little difference.
Unfortunately, WiFi doesn't operate in free space: it operates in a complicated sea of reflections from walls, people, ...
- 174k
23
votes
Why is wired Ethernet losing its speed advantage over wireless?
So why is wireless transmission catching up to Ethernet in therms of transmission speed?
Wireless is not catching up to Ethernet in terms of transmission speed, but it is becoming fast enough that ...
- 18.2k
22
votes
What innovation made WiFi amenable to mobile devices without prematurely depleting them of power?
In June 2004, the Economist,
A financial / economy magazine should be read with a lot of caution when it comes to technical claims made therein – the people writing, interviewing, editing such a ...
- 100k
20
votes
Are TV coaxial cables compatible with WiFi antennas?
So you want to transport that 2.5 GHz (or even 5 GHz ?) Wifi signal over TV COAX cable ?
Indeed to the non-RF people you'd just think that would work. And it does BUT there will be almost no signal ...
- 81.4k
19
votes
Why is wired Ethernet losing its speed advantage over wireless?
So why is wireless transmission catching up to Ethernet in therms of transmission speed?
Money. Time is money, but convenience is REAL money.
Because the speed-per-user cost is relatively low, and ...
- 23.2k
16
votes
Are antennas specified for a certain frequency?
Antennas are tuned for particular frequency bands. They won't be damaged by using other frequencies (in theory the transmitter could be damaged by a mismatched antenna, but most commercial ...
- 20.3k
16
votes
Which signals (Wi-Fi, mobile phone, and GPS) can reliably be blocked by aluminum foil?
Aluminum foil is more than thick enough to block plane waves of these frequencies (ballpark 1GHz) to a high ratio.
It is not easy to employ in practice, however. Seams are transparent to RF fields, ...
- 45.6k
15
votes
Accepted
ESP8266 - is it used in real industry?
The ESP8266 chip is relatively new to the market (circa 2014, I think). So it's short market availability has limited its adoption somewhat -- some early adopters have chosen it, but that's usually ...
- 709
15
votes
Through-Glass WiFi Antenna
Parallel capacitor plates of 25 mm by 25 mm seperated by 4mm of glass with a relative permittivity of 4 would give a coupling capacitance of about 5 pF. That capacitance is in series with an antenna ...
- 473k
15
votes
Why is wired Ethernet losing its speed advantage over wireless?
There's room for argument about some of the details. For example, I've omitted some of the rarely-used standards such as the original 802.11 and 802.11a, as well as some of the early 100 GBps Ethernet ...
- 3,689
15
votes
Why is the bitrate of infrared smaller than the bitrate of WiFi?
Even free-space IR connections can be quicker than you think - or at least they were 20 years ago.
Consider some of the IrDA standards for line-of-sight IR. They can get into the hundreds of Mbit or ...
- 3,090
14
votes
Accepted
What is the purpose of the elements of this antenna?
It seems to be a patch antenna array, analogous (among many images you could find googling around) to this one:
Patch antenna arrays are a special kind of microstrip antennas. You can find many ...
14
votes
Why are there no WiFi earbuds?
Although the answer from Marcus Müller is good, he leaves out an important factor: standardization. This is not the same thing as market share. Wi-fi is a general-purpose protocol designed to carry ...
- 251
13
votes
Accepted
WiFi antenna understanding, which is 2.4, 5 GHz
The USB Wifi adapter you mentioned has two antennas. Each of these operates on both 2.4 and 5GHz bands per the specification-"2.4G/5GHz Dual-Band 5dBi dipole antenna".
The reason you have 2 ...
- 1,504
13
votes
How is Wi-Fi throughput so high?
The Shannon-Hartley channel capacity equation tells us that:
$$C = B \log_2 (1 + S/N)$$
Where C is channel capacity, B is channel bandwidth, and S/N is signal to noise ratio.
The reason WiFi has made ...
- 58.2k
12
votes
Does living next to an electrified railway cause WiFi outages?
First off: do really try to be 100% sure that the wifi isn't available, and not just the internet connection through that wifi. It'd be sad to figure that out later on. Smart phones do report Wifi ...
- 100k
12
votes
Does living next to an electrified railway cause WiFi outages?
Many years ago I was asked to consult on a flawed speed-controller in an European electric train system. As result, I acquired some awareness of electric train speed controller waveforms and switching....
- 35k
11
votes
Through-Glass WiFi Antenna
I never fully understood how or why it worked
Well, it's not magic ;-)
Actually it can either be done
magnetically using coupled inductors. This is like a transformer without a magnetic core. ...
- 81.4k
11
votes
Accepted
How is the esp8266 is able to generate 2.4 GHz wifi signals?
The radio contains a voltage controlled oscillator that is locked to an external reference oscillator using a phase locked loop (PLL). This results in a very precise high frequency signal for the ...
- 41.6k
Only top scored, non community-wiki answers of a minimum length are eligible