Short for Radio-Frequency. Frequencies at which radiation (intentional or not) plays a role. Typically associated with wireless communications, but also relevant for high-speed PCB design.

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3answers
75 views

How to chose an IF, or how bad is zero-IF really?

In a superheterodyne receiver, what must one consider in order to chose an intermediate frequency? Specifically, I'm working on a radio telescope project. It is basically a superheterodyne receiver ...
0
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1answer
34 views

How to determine antenna noise power?

For a 1.4 GHz radio telescope project I'm working on, I need to know the power level of noise an outdoor dipole antenna will be outputting in order to determine the amount of amplification needed. ...
3
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1answer
79 views

Analyzing this RF circuit

I'm trying to analyze this RF circuit: This circuit is designed for about 915 MHz operation. I'd be happy in fact understanding this smaller section of the circuit: I have been trying to find ...
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0answers
17 views

Exchanging packets over an nRF24L01+

I have two nRF24L01+ chips each attached to a Bus Pirate. I'm trying to write some code to test exchanging packets between them, at first entirely on my laptop before I eventually move out to an AVR ...
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1answer
32 views

Impedance line matching and component value matching

I have the following circuit for the SIM900's antenna connection, using the A10393 antenna from digikey: In closer look: First of all my knowledge on RF design is not great. My questions now are ...
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1answer
70 views

RF load (terminator) at the end of RF attenuator

Do I need to install RF terminator at the end of RF attenuator? Let's say that max power output for RM port is 50W and I'm using 100W 50dB attenuator. What if I was using 50W 40dB attenuator? Is there ...
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0answers
96 views

Would anyone explain this circuit? [duplicate]

I know that the transistor works as an amplifier but I can not understand why it is connected this way. I'm a beginner in electronics and I just want an explanation for this circuit (especially the ...
0
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2answers
124 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 ...
2
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1answer
37 views

Is RF Transformer Impedance Significantly Affected by Wire Size?

I'm building a Softrock Ensemble III HF Receiver. The online instructions are pretty good, but have a few remnants from an earlier version that no longer apply. So, despite the discussion about the ...
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1answer
30 views

S-parameter measurement of a 3-port splitter

I am looking for possible ways to measure s-parameters of a 3-port power splitter (1 input and 2 outputs). It is similar in concept to a wilkinson, but also provides matching and none of the ports are ...
0
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0answers
43 views

How to replace all the arduino shields with just one [closed]

I came to know about a shield named 1shield by which we can use our android phone as many shields like g-sensor, GSM and etc. So this product is not available in my country and, can I replicate it ...
0
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1answer
28 views

Piezoelectric Transducer, effect of voltage amplitude vs frequency of pulsing signal?

I am not an expert in piezoelectric transducers used for ultrasound applications so I am looking for some insight into the matter. To extract the greatest amount of acoustic energy from the ...
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0answers
38 views

RF frequency based question [closed]

which is the component used to tune Radio frequency?? which is the component used to tune Radio frequency??
1
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1answer
32 views

Reduce Interference in Wireless Mesh Network

I am playing with the idea of mesh network path finding. The goal is that each node can find the most efficient path through other node to a hub. One way I could approach it is by flooding the ...
0
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1answer
42 views

Parsing .s2p data through an automation script to plot graphs of the various s-parameters

Need to find a way to quickly decipher and plot s-parameters for tons of .s2p files in a short period of time. In specific, I need to plot the angle of the s-parameters versus frequency and then the ...
0
votes
1answer
79 views

Two-stage amplifier

This is my first time designing a circuit by myself :) The input of this circuit is the output jack of my MP3 Player. The output of this circuit is 4-Ohm loud speaker (sometimes I connect 8-Ohm ...
0
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1answer
45 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
17 views

reflection and transmission coefficients when not given information of second medium

I need help with only part (A). I am stuck on this question, i have to find transmission coefficient and reflection coeeficient. I don't know how to get this, I don't have any information from the ...
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1answer
86 views

Using attenuators to damp reflections on transmission line?

I have a 3m long transmission line that transmits a 100ns bipolar square pulse every 200us. At the beginning of the coax cable is a pulsing circuit board, that generates the waveform, then it sends ...
0
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0answers
19 views

WS-RX-02 Receiver Range in Arduino

I have been preparing the receiver using WS-RX-02 receiver and arduino Uno R3 board. My connections are as follows. 3 GND PINS on RECEIVE UNITS are Connected to GND of ARDUINO 2 VCC PINS on RECEIVER ...
0
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1answer
29 views

Any Way of Converting Several 2-Port S-Parameters Measurement to 4-Port S-Parameters

I have a bi-driectional coupler and attenuator (att) in which I would like to capture its s-parameters: So I measured 2-port s-parameters between ports 1 & 2, 1 & 3, 1 & 4, 2 & 3, 2 ...
1
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1answer
104 views

Would you help me understand this simple circuit?

I have three questions: Is it common emitter or common collector (emitter follower) or something else? How do you recognize it? What is the function/usage of R1 and C1? Are they for biasing the ...
0
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1answer
66 views

What is the purpose of the following configuration of diodes on an RF line?

I've been told that these are disconnect diodes. However, I am unsure as to what purpose they serve. They are used on the line that sends a signal to a piezoelectric, the return signal from the ...
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1answer
25 views

XBee Power Consumption, RX Current and TX Peak Current

I'm trying to find out the max power consumption for an XBee Series 2 2mW module so as to pick out a suitable power supply for the system. The docs state that it has a TX Peak Current of 40 mA and RX ...
2
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2answers
48 views

Multipath fading in mobile radio systems

Here is the problem that left me thinking: "In a mobile radio system (e.g., cell phones), there is one type of degradation that can be modeled easily with sinusoids. This is the case of multipath ...
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0answers
63 views

Interfacing MP3 player audio output to a simple FM Transmitter

I found this circuit on the Internet that I'd like to modify. Rather than a microphone as the input I'd like to take the output from an MP3 player so I can play music remotely using this circuit: ...
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2answers
29 views

Reading S2P Files - What Does Each Column Represent

I'm having a hard time reading s2p files. For an example say that I am measuring the parameters of a 2-port network (port 1 and port 2). What do each columns represent? I can tell that the first ...
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1answer
44 views

Is it possible to use a XBee module to controll a quadcopter? [closed]

I'm thinking to design my own quadcopter and wondered if it's possible to use a XBee module to control the drone? The reason I'm thinking about an XBee module is because I want to be able to plug it ...
0
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3answers
60 views

Simulate RF transmission lines at Low frequencies

I would like to simulate RF transmission lines in how they propagate, and how impedance mismatches at the end of the transmission line cause reflections and power transfer does not work. It would be ...
0
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0answers
64 views

Would my project be affected by lack of a filter?

I have chosen to do a final project, I will be transmitting bits using a wien bridge oscilator, I want a 160 MHZ sine wave and I have chosen values for it. I have chosen the AD8041 op amp because it ...
2
votes
1answer
120 views

RC toy car RF signal drops out when at full speed

Short version (TL;DR): I need help troubleshooting the radio communication of an RC car that I made. Every 5s or so, the connection drops out and the car spends about 1s without receiving instructions ...
5
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2answers
64 views

How Reflex Klystron works

I have a doubt on how exactly a reflex klystron works(as an RF source). In wikipedia it says that, The electrons are fired into one end of the tube by an electron gun. After passing through the ...
0
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1answer
55 views

Generating Rolling Code with Arduino for RF Switch

I am working home automation using Arduino and TX/RX module. From various sources I learned that Rolling Code based RF Switches are having better security. I have following queries How suitable it ...
3
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1answer
53 views

How to reduce objects/hands impact on PCB antenna efficiency

I am trying to learn about planar inverted F antennas creation and have designed two different designs for two different frequencies with success. One seems pretty much unaffected by the proximity of ...
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0answers
34 views

RF Receiver sniff encryption

I am trying to build a home automation system using Arduino Uno R3 and transmitter and receiver module. I will be buying a RF remote switch. RF remote switch specification says it uses pairing coding ...
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votes
1answer
57 views

How can i send bits using a wien bridge oscilator?

so i have a string of bits that my shift register will be outputting one after another, i wanna use a wien bridge to send them into air. if a bit is a "1", i want the wien bridge to send a wave, and ...
0
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1answer
50 views

BJT Topologies - Design Principles at RF

Here are some rules of thumb I've learned when designing single-transistor BJT amplifiers: High input impedance is good Low output impedance is good Biasing resistors should draw ~10% of the ...
0
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2answers
69 views

How do I hold a signal high from one high pulse?

Assuming I send a signal wirelessly to a receiver connected to a fan. if the receiver detects that a pulse is there, it switches on the fan. the fan should stay on until it detects another high pulse, ...
0
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1answer
20 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 ...
1
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1answer
126 views

I want to make an oscillator with 160 MHz

I want this for my project. So I have decided to make a basic Wien bridge oscillator. $$f = \frac{1}{2\pi R C}$$ So if I choose a capacitor of 0.1 nano farads and a resistor of 10 ohms, I should ...
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0answers
14 views

RF Solutions ZULU module

I am trying to set up a remote battery voltage checker that will radio the voltage read from the battery to a computer. I went for the ZULU module (by mistake as I should have brought the ZULU-M ...
2
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0answers
55 views

Does a 40 MHz radio frequency have any interference to Bluetooth signal?

From my understanding, the Bluetooth signal is using a 2.4 GHz frequency. However, when someone is playing with a 40 MHz RC vehicle, the Bluetooth signal keep on getting interrupted or disconnected. ...
1
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1answer
95 views

Help with a RF reciever circuit

Recently I have been working on a basic RF receiver, but my efforts so far have proved fruitless. I designed the following circuit based of of previous research into the topic. According to what I ...
4
votes
3answers
104 views

Impedance matching an RLC circuit (inductor macroscopically drawn on PCB)

Context: I am a physics grad student with basic knowledge of circuits, but impedance matching and RF domain are beyond my normal scope. My PCB is actually copper bonded to a ceramic substrate that is ...
8
votes
3answers
190 views

PCB RF Layout Critique: Input on my radio-telescope PCB

I'm attempting to do the board layout for a radio-telescope we're building at one of my jobs. Here is the overall system topology: QRFH is for "Quad Ridged Feed Horn". It's a rather esoteric ...
0
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2answers
44 views

RF remote with three buttons

I am trying to create an RF remote that has 6 buttons but the RF encoder only has 4 inputs. Is this possible and preferably I would not like to use a separate chip. This is what I am using: ...
2
votes
1answer
74 views

RF Harmonics and Spectrum Analysers

Please forgive the long question. I have split it into 2 parts. I am very confused about how harmonic suppression is measured in RF system (in my case, ham radios). I have picked up a couple of the ...
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2answers
59 views

How to make a RF Additive Mixer for two inputs in same frequency band?

One of the most common designs for a SSB modulator (phase shift method) involves an additive mixer as the very last stage. Here is a block diagram for reference: This additive mixer must provide ...
0
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1answer
70 views

USB to RF bridge: Kettler Ergorace bike

I own a Kettler Ergorace indoor bike. It's possible to create exercises using the USB interface. When plugged into a PC, it is shown as a virtual com port (SiLabs CP2102) I would like to control it ...
1
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1answer
56 views

Determine the working frequency band of unknown RFID chip

I have a passive RFID chip from which I would like to scan the ID. I have a standard USB RFID Reader, but this doesnt print out anything. This reader scans the 120–150 kHz range, so the chip must ...