Tagged Questions

Using other than a wired connection to transfer signals or power. Includes optical and (ultra)sound, but most often refers to RF (radio-frequent). Distances can be as low as centimeters (e.g. RFID), there's no upper limit.

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2answers
79 views

How to start LED wirelessly in a very compact and cheap module?

I have been thinking and researching about this issue for a while with no success. I am hoping someone can solve this problem in the community. I want to have many small modules each with a small ...
0
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0answers
31 views

Is possible to get very narrow beamwidth antenna?

Is possible to make 60 dBi sector or patch antenna by make its beam width 0.17°/0.17° only ? how to calculate ideal dimensions against frequency at this range of beam width ?
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1answer
39 views

Design of 5 - 15 MHz Voltage Preamplifier

I'm trying to design a power amplifier for the HF band to drive an inductive charger. The stage I'm working on now is a voltage preamplifier which needs to be able to amplify 1 Vpp to 10 Vpp. The ...
4
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1answer
56 views

ZigBee vs WiFi for wireless communication

I've been working on a product using WiFi. The reason I picked WiFi, is cause I essentially have 20-30 nodes communicating to a main node via a router. This all works very well, and its easy as its ...
0
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2answers
108 views

Is possible to build -168 dBm amplifer?

we know that GPS receiver can reach sensitivty of -168dBm, and also it is possible to make receivers with similar sensetitvity can operate at another bands/frequencies . but I just want to know if ...
0
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1answer
60 views

Data transmission in ocean

What is the greatest depth where we can communicate with the submarine over the sonar system in ocean? Also, how can we calculate how much data can be transmitted using this method?
0
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1answer
33 views

Fastest short-range (millimeter) wireless data transfer rates? [closed]

This question asks about the limits of wireless data transfer rates. I'd like to know what speeds have been accomplished, and more importantly, some of the design details of their underlying systems ...
2
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1answer
42 views

How is CPM Modulation Different from PSK?

Continuous phase modulation has been described to me very similar to wikipedia's definition, which basically indicated that the CPM is different from QPSK, for example, because QPSK abruptly shifts ...
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0answers
34 views

Packet Loss decreases as the nnumber of nodes increases, isn't it counter-intuitive?

I am reading the results of a research publication about clustering algorithms. The results show that the Packet Loss decreases as the number of the nodes increases. This is a bit counter-intuitive ...
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0answers
25 views

What are the most important metrics for evaluating the quality of a communication protocol

In a discussion with some Phd students I heard them mentioning Packet Loss Rate, Channel Utilization and Delay are the main metrics to evaluate the quality of a (wireless) communication channel. What ...
0
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0answers
60 views

1 Mbps satellite channel with a 270 ms delay

Consider 500 byte frames sends on a satellite channel with a 270 ms delay on send an receive by 1 Mbps rate. by ignore the length of ACK message and using Slide Window technique, how many bits need ...
0
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2answers
73 views

How wireless communication works?

When an AC signal is transmitted through a conductor, direction of flow of electrons is continuously alternated. In wireless communication signal is transmitted through air, in this case which ...
0
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1answer
44 views

How to make a USB receiver for the wireless mouse? [closed]

I have a Microsoft Wireless mouse but the USB receiver is long lost. Is there anyway I can make the receiver myself?
0
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0answers
37 views

Form of the received signal in a MIMO communication

I am reading an article which is related to MIMO communication networks. Consider that there are \$U\$ users, each of them have \$J_{u}, u=1,...U\$, different layers. We want to calculate the received ...
1
vote
1answer
81 views

Making Device to Send Data to Smartphones: 100m range, 1kb/s bandwidth, low power

What I want to make: A device that immediately sends a notification if the device incurs a moment of high acceleration. The notification needs to denote the acceleration. There is no guarantee that ...
0
votes
0answers
38 views

Remotely Toggle Relay

A while back I decided I wanted to get into electronics, after which I bought a number of components to get me started, along with the Raspberry Pi and breadboard I already had. I am now wanting to do ...
0
votes
2answers
217 views

2.4 GHz versus 434 MHz transceiver for home automation

I am working on a project that uses an Arduino Uno R3 and will have one receiver and one transmitter. I'm going to use this for home automation within my home in India. I want to know which ...
0
votes
1answer
34 views

A question about temporal diversity

I am reading a survey. In that survey the author talk about "Temporal diversity" I can guess what is the meaning of that. But he also announce one way of making Temporal diversity is channel ...
0
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1answer
50 views

How do multiple users connected to a wireless router receive their signals?

In other words how does a wireless router with multiple users work? I know that routers use electromagnetic waves radio waves, but how does information get sent to the user it is intended to? and if ...
0
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0answers
68 views

Accelerometer (or something else) to detect rotary oscillations

I'd like to detect oscillations of a rotating disk. If an heavy weight object is placed in the wrong way on the rotating disk, the rotation it's not anymore only on a straight plane (perpendicular ...
0
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0answers
50 views

AT86RF212b connections

I'm trying to communicate at86rf212b with atmega328 , I have connected all SPI connections( MISO, MOSI, SCk, SS), IRQ, SLP_TR and RST with suitable 5v/3.3v conversion (74hc4050) and trying to read ...
0
votes
2answers
86 views

Best way to wirelessly transmit and receive data

I'm working on a project that requires wireless transmission and reception of data. I wonder what the best technology would be. It is not tons of data maybe not even a kilobyte. And the range should ...
0
votes
1answer
32 views

ISM RF link problem

I've established an RF link using TWS-CS-2 as a transmitter and AM-HRR3-433 as a receiver. The carrier frequency : 433.92MHz. Modulation type : ASK. ATtiny25 to generate and decode Manchester ...
0
votes
1answer
57 views

Radio direction finding - dependence on source signal type

I want to make a robot that can track the direction of the transmitter that is controlling it, for example to aim a camera at the transmitter. The robot vehicle will be controlled by a 2.4ghz ...
1
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0answers
78 views

Wireless Mesh Sensor network comparisons [closed]

From your past experiences (don't need a whitepaper): Could you guys compare Zigbee, Z-Wave and 6LowPan? Please also include information about compatibility with regular internet protocols. I think ...
0
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2answers
173 views

Long range Arduino communication

The project must be able to detect the amount of water in tanks and transmit the information to a farm house it must be wireless and unfortunately there is no cell phone reception in the places that ...
25
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5answers
4k views

Why 2.4 GHz Band?

Bluetooth, WiFi, Zigbee, Remote Controls, Alarms, Cordless Phones etc.. Why all of these protocols, devices, etc. use 2.4 GHz band instead of 3.14 GHz. What is so special about it?
1
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0answers
76 views

Insufficient Power when using one power source vs two [duplicate]

So I've been working on a wireless remote relay switch using several components and have struck a break wall. The issue I'm having is that the D0 siginal output triggers the relay but only at short ...
0
votes
1answer
50 views

Distance confusion about Shuncom SZ05-ADV ZigBee module

I ordered this module looking at the datasheet that it has a range of 2000m LOS distance. But now when I test it, I can receive signal from a maximum of 50m distance! It sends 2.4GHz signals. As far I ...
0
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0answers
26 views

What wireless sensor network should I choose which can be customized with respect to hardware?

I am looking for a WSN OS which can accommodate approx 100 sensor nodes. I had looked at various available WSN OS like TinyOS (source code is available at GitHub) and Contiki and others but they all ...
7
votes
7answers
320 views

Measuring direction of object (or angle of signal origin)

I am interested in somehow tracking the "compass" direction of a moving object from a reference-station -- in other words, something similar to submarine sonar systems (although I'm unsure how those ...
0
votes
3answers
63 views

Synchronized pulse generation from wirelessly connected boards

I want two or more boards (less than 10m range) to generate a LED blink at same time, within 1 ms difference, using wireless communication. First, due to power consumption, I am thinking to use ...
1
vote
4answers
66 views

GPS Antenna Selector: How to electronically select one antenna from multiple available antennas?

I want to connect multiple GPS antennas to a single GPS module and select one of them based on some logic. Basically, I want the module to receive signals from only the selected antenna. Is there an ...
0
votes
1answer
333 views

SC2272-M4 Behaviour when using relay SRD-05VDC-SL-C 5V DC

I'm currently encountering a problem when using a relay switch with a 5v receiver. When using the same receiver with a row of LEDS it works flawlessly. I've noticed that the relay keeps making the ...
1
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2answers
49 views

Could transmit/receive turnaround be improved by having a heterodyne receiver switchable between high-side and low-side injection

In some of the small radios I've worked with such as the Nordic Semiconductor 24LE line, there is a significant (100us+) delay between transmitting data and being able to receive a response. By my ...
0
votes
1answer
116 views

Why RTS/CTS do not solve completely the hidden terminal problem and exposed terminal problem?

I was doing some reading online and textbooks about the RTS/CTS protocol for wireless transmission. Although, the textbook that I read said that the hidden terminal (and exposed terminal) is solved by ...
2
votes
3answers
108 views

What is Doppler Spread

What is the plain English explanation of the Doppler Spread? Looking at different sources I come across complicated definitions which I struggle to understand. Example for such one: Doppler ...
0
votes
0answers
14 views

How do Coherence Time and Coherence Bandwidth influence the decision on the diversity scheme?

I came across a statement in a lecture slide which states: Coherence Bandwidth and Coherence Time govern our decisions about the diversity scheme that we would choose The lecture is in the field ...
1
vote
1answer
60 views

Controlling various Arduinos with Android

I have an upcoming project which requires me to use about 8 different Arduinos, probably more. They all perform a light show which turns off and on various LEDs at different timings to simulate a ...
0
votes
1answer
100 views

Antenna Diversity: two Yagi antennas to the Rx and Rx/Tx u.fl-male points on the wifi-NIC?

I looked at the BCM4312 file - available as as doc or a pdf - and it says: BCM4312 has 2 radio chains, one is a dedicated Rx chain, the other is shared by TX and > RX chain using an RF switch ...
0
votes
1answer
46 views

Remote Wireless 4CH Switch On/Off - Data PIN Network Cable

Planning Stage I'm in the planning stages of making a wireless on/off switch that will basically cut off pin 6 on a network cable. I know little about electronics and I've attempted to learn as much ...
0
votes
0answers
71 views

Why is it that using RTS/CTS in 802.11 improves its throughput?

There is a famous paper which has shown that using the RTS/CTS scheme for medium access improves the throughput of a 802.11 system compared to a classical medium access scheme. The paper: ...
2
votes
2answers
66 views

What makes DSSS a more robust transmission technique compared to FHSS?

In many textbooks it is stated that DSSS is more robust than FHSS. Especially in terms of interference and delay spread? What is the exact reason. Lets say we multiply a given bit 1 with a larger bit ...
0
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3answers
263 views

Is it possible to measure the distance of a WiFi access point from the receiver?

I have signal strength in dBm and frequency in MHz is is possible to find the distance?? Any idea about how to do it?
0
votes
1answer
61 views

Plain English explanation of the Space-time Code Block by Alamouti

I checked about the Space-time code block online, but all of the explanations are either short or too simple, or too mathematical and complex Could anyone here provide an explanation of what ...
1
vote
1answer
73 views

How to transmit CAN signals wirelessly without line of sight (LOS)

I have a scenario where I have an OBD-II interface transmitting data via CAN across six wires to a display. I will have power on either side of the wires, but I cannot assume that the wires will have ...
0
votes
2answers
43 views

How are the Intersymbol Interference and Symbol Time (duration) related to each other?

In a lecture slide I noticed that OFDM(Orthogonal frequency-division multiplexing) mitigates the problem of Intersymbol Intereference over wireless systems because the symbol time is increased, in ...
2
votes
1answer
47 views

Upload XBee firmware without a PC and XCTU

So, as the title suggests, I would like to know if there is a way of uploading a firmware to a XBee module, throug the serial without a PC. What I mean is, I have a microcontroller, I would have the ...
1
vote
3answers
62 views

Using Bluetooth 4.0/LE verses RF

I am asking this question in hopes to get a solid answer from anyone who has direct experience dealing with the most recent RF as well as Bluetooth 4.0/LE developments. What I am essentially trying ...
0
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2answers
47 views

the response of wireless channel to an input

I am reading the wireless of David Tse. In the 2nd chapter of this book there is a discussion about the response of the channel due to an input. It has said that since the channel is linear its output ...