All Questions
Tagged with antennas electrical-engineering
22
questions
-4
votes
2
answers
82
views
Can we catch signals from a cellphone using an external device? [closed]
What if someone stole em waves from our mobile devices to listen to our conversations or get our OTP. Whatever encryptions they have they are just EM waves innit and they cannot be propagated only in ...
1
vote
2
answers
62
views
EM wave emission from earphone wires due to varying current signal
if we listen to some audio signal on a wired earphone, then does the wire of the earphone act as a transmitter antenna to emit the audio signal as radio waves even though its strength might be ...
- 23
-1
votes
1
answer
93
views
How does an antenna work?
I'm looking for a model of an antenna that would explain how it works an in particular where the values of impedance like 36.5 ohms come from. I've tried looking but everything i found was overly ...
- 31
-1
votes
2
answers
72
views
From the physics standpoint, how should I align a USB Internet stick relative to the nearest cell tower in order to have the best signal? [closed]
I use this USB Internet stick:
(Huawei E3372h-153)
To connect to the Internet, I simply insert a SIM card into this stick and then insert the stick into a USB port of my laptop.
Based on my ...
- 1,599
0
votes
0
answers
45
views
Mathematical Modelling of Wireless Power Transfer
I am trying to understand the interaction between a transmitting antenna with a certain transmitting power (denoted PTX in the diagram) and how the radiation pattern of the TX antenna is affected by a ...
- 11
1
vote
1
answer
132
views
How do electrons flow in a "random single wire antenna" of a Raspberry Pi, which is DC and just have one path? (no gnd)
I have been amazed by the fact that just by inserting a cable in a GPIO of the raspberry pic acts like an antenna, as far as I know, electromagnetic waves are generated when there's current, and also, ...
- 11
0
votes
1
answer
144
views
Using ham radio to communicate with an underground crew [closed]
In "Stranger things 3" Dustin uses a ham radio named Cerebro (an image https://www.reddit.com/r/StrangerThings/comments/fhrdml/will_cerebro_make_an_appearance_in_st4/) stationed on a hill ...
- 13
2
votes
1
answer
85
views
What is the explanation behind radio shadowing by people?
I called it shadowing but masking may be more appropriate, feel free to suggest a better question title after you read the following.
I have an old clock alarm radio receiver that plays at the center ...
- 3,236
1
vote
0
answers
28
views
In an AC Current, if the voltage is high, does this "amplify" the radiowave emissions without changing the frequency?
Hello
My question comes from my interest in antennas i suppose:
I understand that antennas utilize alternating current to generate EMF Waves along a particular frequency depending on how quickly the ...
- 53
5
votes
2
answers
3k
views
How come a mobile phone signal is blocked by aluminium foil, but Wi-Fi gets through?
Major puzzle for me. I have done a demonstration in lectures for years now, where I show that a mobile phone call can be blocked by wrapping the phone in a single sheet of standard Aluminium kitchen ...
- 133k
0
votes
1
answer
27
views
Is there any factors depends for electromagnetic waves?
I am staying in hostel. One person said me that he is getting better connection with the wifi when the door is opened.
I am wondering that what an electromagnetic wave can do with the door?
Is there ...
- 1
2
votes
1
answer
402
views
Is a radio receiver antenna a capacitor?
I think so, but its capacitance should be very small, so how can the antenna correctly receive the signal, the low capacitance wont bother the signal?
- 797
0
votes
1
answer
529
views
Patch antenna excitation
How can we excite the patch antenna in different modes like TM10 and TM30? If a microstrip patch antenna resonates at TM10 mode can it resonate in other modes also like TM30?
- 11
0
votes
1
answer
797
views
About The foxhole radio: coil rotation times, whether capacitor's needed
I recently tried to make a DIY [foxhole radio] (https://en.wikipedia.org/wiki/Foxhole_radio). Althogh, I made it according to the manual (140 times coil rotated, ground (220V), blue razor blade, ...
- 19
0
votes
2
answers
569
views
How do radio-frequency transmission work?
Are sound frequencies (20-20,000Hz) included in radio waves? If not, how does sound get to our end (radio/receivers)? Is there some type of encoding going on inside those radio-frequency waves or ...
- 1