47
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 ...
- 81.2k
39
votes
Accepted
Is it possible to jam wireless home alarm systems?
A "denial-of-service" wireless attack is very easy. It will disrupt radio communication between sensor and panel. Hopefully, the panel is smart enough to detect that one (or more) of its sensors has ...
- 27k
29
votes
Accepted
Why are many IR receivers in metal cages?
[ added 2_D resistor_grid methodology for exploring shielding topologies ]
You want that IR receiver to respond to photons, not to external electric fields. Yet the photodiode is a fine target for ...
- 34.6k
23
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 ...
- 73.3k
21
votes
Is it possible to jam wireless home alarm systems?
First of all, to clear some things up: All digital signals are built up by analog signals. As already mentioned in the comments, all wireless communications can be jammed, encrypted or no. And last ...
- 3,807
16
votes
Accepted
Why do cell phones sometimes interfere with amplifiers
The usual problem with interference from GSM cell phones is caused by rectification of the strong RF signal at the semiconductor junctions at the input of the amplifier.
GSM uses Time Domain ...
- 33.8k
14
votes
Why does a 50 Hz, 200 mV sine wave appear sometimes on my portable oscilloscope without a probe connected to anything?
The probe may be characterized by a capacitive coupling.
This make the probe acting like an antenna receiving 50 Hz as power lines radiations.
14
votes
Can two interfering light beams create radio waves?
Yes, however you would need a nonlinear optical medium to get mixing such that sum and difference frequencies are generated.
In a linear medium like air or vacuum, adding and subtracting does not ...
11
votes
Radio static due to neighbor's shredder
Take a look on the bottom or back of your radio. You should see something about FCC rules Part 15:
(Source)
In particular:
This device must accept any interference received, including interference ...
- 34.8k
11
votes
USB shielding, device or host side?
How to connect cable shields
a.k.a: A short summary of Henry Ott's approach in Electromagnetic Compatibility Engineering (2009).
Foreword
Does it matter if the shield gets shorted to ground on the ...
- 7,267
10
votes
Does a twisted pair cable radiate more EM radiation than non-twisted pair?
Yes, it is vice-versa, through the principle of reciprocity.
Any "antenna" is just as (in)effective at transmitting as it is at receiving, so the advantages of twisting the conductors together apply ...
- 177k
10
votes
Can two interfering light beams create radio waves?
The assumption in the question is: If one wave at a high frequency \$f_1\$ and another wave at a similarly high frequency \$ f_2 = f_1 + \epsilon \$ are added together, it's possible to obtain a new ...
- 7,267
9
votes
Accepted
What are some quick, cheap hacks for determining the source of EMI in my house?
A yagi antenna and a cheap SDR might be good to play around with. Make sure the antenna and SDR work in the frequency range of interest (so if you want to look for wifi signals, then the antenna and ...
- 87.2k
9
votes
Can two interfering light beams create radio waves?
By interference (meaning linear addition) it is not possible to generate an RF (radio frequency) signal because linear addition does not generate new frequency components. However, it is possible by ...
- 1,735
9
votes
Accepted
Why are green pair (or orange pair) wires not adjacent in RJ45 connectors?
Legacy. Isn't it always.
For POTS (telephone) the RJ11 jack used a single pair in the middle.
The design of the jack series was such that as the number of pairs increased they would build out from the ...
- 68.8k
8
votes
Accepted
Long wires causing Raspberry Pi to die?
The wire has inductance and, the longer the wire is the more inductance it has. An inductance likes to maintain the current flowing through itself so, when your switch opens, the small stored energy ...
- 467k
8
votes
Radio static due to neighbor's shredder
The dipole antenna connected to the Bose Wave Radio might have a pretty good null off the ends. Since your neighbor is in the apartment above you, it's worth a try using that null to reduce the ...
- 5,909
7
votes
Accepted
Why is an HDMI signal causing interference with Over-The-Air digital television?
ATSC is an all digital feed. As such math, can be used to compensate for weak and / or corrupted signals. This can be done to such an extent that the recovered data may be indistinguishable from the ...
- 3,399
7
votes
Accepted
433 MHz RF noise problems
Are you using such type of modules?
If yes, then don't expect them to work without proper software noise filtering algorithms. This module will give out data at Rx output even if there is no other ...
- 798
6
votes
Accepted
FCC part 15 "must accept interference from other sources": what does this mean?
"Interference" in this context applies to one, radiated RF signal affecting the reception of another radiated RF signal. The interference is not produced within the interfering transmit ...
- 176
6
votes
Accepted
Transformer vs capacitive vs both coupling to speaker
Option E: None of the above.
None of those have anything to do with your problem.
The problem you describe is caused by RF (radio frequency signals) getting in to the amplifier circuit. The ...
- 73.1k
6
votes
Accepted
Could multiple transmitters on the same frequency work if phase-locked to GPS? (gedanken)
Yes, absolutely. The physics work how you think they do - the radio signals just add up. In fact you don't necessarily need GPS as (I think) you could use the radio waves themselves for ...
- 12.6k
6
votes
Accepted
Why is inductive coupling negligible at low frequencies?
I've been reading some papers from the early telephone era. I see a lot of statements thrown around like "crosstalk at low or voice frequencies, where inductive coupling is negligible..."
...
- 17k
6
votes
Can two interfering light beams create radio waves?
In vacuum and linear media (read: most situations), two lasers of different frequencies do linearly superimpose, meaning that the sum of two electromagnetic waves with different frequencies simply ...
- 98.3k
5
votes
Will this PCB trace GSM antenna be affected by EMI?
Apart from EMI issues, I have a hard time believing that this will work at all. Is there a reference design available for something similar? From what I would guess (I'm not an antenna specialist at ...
- 8,089
5
votes
Is it possible to jam wireless home alarm systems?
Yes, it is possible to jam wireless alarm systems, probably even with low-cost, low-tech DIY devices (google "broadband jamming DIY"). There are a couple of articles online which report successful ...
5
votes
How to know which radio frequency is free to transmit data over a particular frequency to avoid interference
In general terms, equipment on any band needs to be licensed for use there.
Some bands are licence-free, such as the 433MHz band in Europe, the 902MHz band in USA or the 2.4GHz band world-wide.
In ...
- 21.6k
Only top scored, non community-wiki answers of a minimum length are eligible