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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47 views

Calculating the “ball-park” range of a transmitter including dBi

I'm looking to buy a tranceiver that has a LOS range over 100m at minimum 1kbps. (preferred 28kbps). I've been looking at this device I'm using this calculator and I'm getting over 180 miles which ...
2
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1answer
34 views

How does Altium Designer's “impedance constraint” feature work?

Altium has a design rules option for setting a track width constraint according to line's impedance (e.g.; 50\$\Omega\$). How do I use it? Please give me instructions or a link to an online tutorial. ...
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3answers
28 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 ...
2
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3answers
111 views

RF transmitter circuit explanation

I just can't get my head around how these RF transmitters work: simulate this circuit – Schematic created using CircuitLab What I do know about them is the following, correct me if I am ...
3
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3answers
116 views

loop area and EMI

I always hear something like "reduce the loop area" when reading materials on EMI reduction. Why we need to minimize the loop area? I have two guesses: Smaller loop area will influence less signal ...
3
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0answers
82 views

How to avoid regulatory approval regulations, when chosing a RF module?

I've been trying to implement RF capabilities into my projecto, but I don't want to pay thousands of euros to get an ETSI certification in case it gets into production. I know that if I get a complete ...
0
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1answer
17 views

Displacement current generation in dielectric and in vacuum? How is it different?

I understand how the displacement current work in dielectric such as in parallel plate capacitors but don't know how they would work in a vacuum where there is no dielectric present. Can someone ...
0
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1answer
42 views

Improving reception of 318MHZ remote control

We have a gate opener with keyfob-type RF remote transmitters that operate at 318MHZ. The range from inside the car is about 75 feet -- less than we'd like due to the time taken by the gate ...
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2answers
49 views

How to protect a RF chip from thunderstorm static electricity?

I'm working on a open-hardware wireless wind sensor. It's designed for being installed on mountains, where thunderstorm are quite often. I use a Si4461 RF chip, with a half wave whip antenna. My ...
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0answers
48 views

Getting the best range with XBee-Pro 900 XSC S3B

I have a pair of 900 XSC S3B xbee pros and a couple 2dBi duck antennas. I just did a simple outdoor range testing and only got about 2,000 feet. I was outdoors without any buildings in the way, but ...
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2answers
57 views

Perform digital modulations (HW or SW)

I am considering doing a project which revolves around microcontrollers (AVR, or arduino) and digital modulation to learn about digital RF. I have simple things in mind, just for experimentation. ...
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60 views

saw resonator based low power RF transmitter

I am basically trying to design a RF transmitter and receiver using the saw resonator. the values I am using for the circuit are: C1= 5pF, C2= 18pf ,L1= 33nH, RF bypass (Ceramic cap) = 470pf, R1= ...
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1answer
88 views

What is the difference between peak-power, average power and true RMS power in RF measurement?

What difference between peak-power, average power and true RMS power in RF measurement? I have read a peak-power measurement can calculate average power measurement also. Does any of these needs ...
0
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2answers
83 views

What power is measured by a spectrum analyzer?

Is the signal level that is shown in a spectrum analyzer power of the signal being measured. If yes then what power is it: average power, true power or peak power? Also when using a power meter for ...
3
votes
2answers
54 views

RF Wakeup - Battling power consumption

I am currently using two nRF24L01+ (2.4 GHz RF transceivers) together with two AVRs to create a keyless entry system. My problem is battery lifetime when using a CR2032 battery to power the key. The ...
2
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1answer
96 views

Choosing capacitors for Microwave RF application

I've recently been given a project to lay out some PCBs which will contain a few Mini-Circuits RF amplifiers, and their associated biasing components. However, since I need to have several stages of ...
0
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1answer
14 views

Need some RF help - integrating with a Xemics DP1203 transceiver

So there are some devices (timing photogates) that use these chips (DP1203C915) to send data out over RF at 915MHz to a box that performs timing and split-time calculations. I would like to be able ...
3
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4answers
307 views

Non linear device with two frequencies

I got this on an interview question and I still don't know the answer. What output will have a nonlinear device if we will give two random frequencies \$f_1\$ and \$f_2\$? I answered that it ...
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3answers
89 views

Wireless EEG electrode design

Currently, all 'wireless' EEG systems acquire signals from electrodes which are wired to an amplifier, a filter, a digitizer and then finally a wireless module. I want to design a system that's ...
2
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1answer
476 views

Does amplitude of FM signal even matter?

Thinking about FM modulated signals that store information only in frequency so that their amplitude has no effect on the sound, I began to wonder: Does the amplitude even matter in the end? Well, ...
0
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1answer
36 views

Bandpass Filter Balanced Ports?

I have a question regarding bandpass filter. What is unbalanced port and balanced ports? I noticed that outputs of balanced ports are connected to RF_P / RF_N of Zigbee IC. What are RF_P / RF_N?
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1answer
75 views

What signal will come in?

I have a simple setup as shown, I would like to know what kind of RF signal will come in? Since the filter is configured around 2.4GHz, will all ISM (WiFi, Bluetooth, Zigbee, etc.) come in? The ...
4
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2answers
417 views

Robot following you; what's the best way?

I built a human-sized robot that can follow anyone wearing an IR beacon. It works quite well indoors and it's quite precise, but outdoors it is completely blind due to sunlight infrared. I have a ...
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0answers
31 views

Push-on coaxial connector with RF leakage performance comparable to threaded-coax connector?

In examining the performance characteristics of the push-on SMP connector I've noticed that the RF leakage is at best -80dB @ 3 GHz and then continues to degrade as the frequency increases to -65 dB ...
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3answers
144 views

900 MHz vs 433 MHz for urban environments

At ranges of a few hundred meters, will there be an appreciable difference in performance (ie range, bit rate) between 900 MHz and 433 MHz for digital applications in an urban environment? Forgot to ...
0
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2answers
51 views

How does Signal-Noise-Ratio related to receiver power

If I have the instaneous Signal-Noise-Ratio (of the receiver), but no other information, and I am interested in the instaneous \$\mathbf{Power_{received}}\$, is there any relationship between these ...
1
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1answer
84 views

PC to Arduino wireless link (low latency)

I want to build a robot car with an camera gimbal on top of it. This robot and gimbal should be controlled wireless by a gamepad and the head tracking of an Oculus Rift. As it is with the Oculus Rift, ...
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45 views

How to calculate Input backoff per carrier of a satellite

I was trying to calculate the sizing of SSPA in my satcom network where input backoff per carrier is required to calculate Power flux density. My current network configuration in C band is Total ...
7
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1answer
172 views

What does sequences like 1-3, 1-10, 1-3-10 etc in a spectrum analyzer mean?

I have read in a paper explaining spectrum analyzer basic 'When selecting the RBW(resolution BW), there is usually a 1-10 or a 1-3-10 sequence of RBWs available. More RBWs are better because this ...
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1answer
82 views

Does there exist a digital wireless broadcast protocol?

EDIT: Thanks very much to @pjc50, @dave-tweed, and @MoJo For their valuable comments. I apologize for the ambiguity of the original question. I've made edits below to clarify. I am in search of a ...
0
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0answers
59 views

Communicate from Arduino to mobile phone using RF

I am looking to send an alert signal from an Arduino to a mobile phone (GSM, preferably Android) The signal by itself is quite small, hence high transmission rates are not a priority. The preferred ...
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0answers
75 views

Electromagnetic field voltage induction

I need help regarding voltage induced in load (cables). Say we have a 10 V/m radio field at 250MHz carrier. It induces 1V to an impedance of 50 Ohm (x length). If the cable impedance is increased to ...
6
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1answer
122 views

A poor man's alternative to a network analizer for antenna matching

I'm doing a small board with a 915 MHz transceiver. A small helical antenna is used, which is located on board with a very short path (10 mm) from the IC, including balun and a matching network. There ...
18
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4answers
513 views

At what frequencies does PCB design get tricky?

I have designed many mixed-signal PCB's where the highest-frequency component is the microcontroller's crystal oscillator itself. I understand the standard best practices: short traces, ground ...
0
votes
1answer
80 views

How to add automatic frequency control to varicap voltage?

I've built a TV tuner radio using a tuner with voltage synthesis tuning and a CD2003 FM demodulator. A similar schematic can be found here. The reception quality is very good, but it is difficult to ...
0
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1answer
56 views

Netduino and RF, on the cheap?

Hardware support for the Arduino is vast, much have already been done and a lot of devices has been tested. Netduino, not so much... But I want to add a RF receiver to my Netduino, so it wirelessly ...
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0answers
83 views

Interpreting Data Sheets (“Typical Applications”)

I've recently been researching various transceivers, but I run into trouble as soon as I get to the "typical applications" section of the data sheet. With the Si4464 for instance, the example ...
3
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1answer
107 views

Antenna matching network. What? Why? How?

I'm designing a small board featuring a transmitter in the 900 MHz band. Since RF is definitely not my strongest subject, I'm basically trying to follow all the datasheet recomendations regarding ...
0
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2answers
76 views

Is it possible to detect cellphone IDs in an enclosed area

I'm working on a project where I need to be able to identify different cellphones in an area. Ideally I need a way to identify when specific cellphones enter and exit a range - this could be IMEI or ...
6
votes
2answers
188 views

How does this quartz antenna work?

I picked up something called a quartz antenna at a surplus store for $2.75 so I could tear it apart. This is what I found: There were two small cardboard boxes filled with loose quartz crystals ...
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1answer
78 views

How do I sniff this RF Transmitter Gate Opener Circuit?

What piece of hardware am I looking for to observe the transmitted radio signal? Would an oscilloscope come in handy here? is this a 2-channel RF remote, a 3channel RF remote, or something else? My ...
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4answers
88 views

How do multiple transmitters and single reciever work?

I have multiple digital transmitters sending packets to an receiver, and packets from different transmitters may arrive at the same time, how can the receiver differentiate multiple packets at the ...
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2answers
61 views

NPN transistor to short RF remote switch button

simulate this circuit – Schematic created using CircuitLab Hi, I am trying to replace RF remote switches with transistors and want to control them using raspberry pi GPIO pins. Here as ...
2
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0answers
35 views

Is it possible to replace a CC2500 with a CC2531?

I have a working Arduino->CC2500 configuration, and I'd like to know if it's possible to replace that with a CC2531 USB dongle. Does the CC2531 have the ability to form the correct packet structure ...
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2answers
70 views

Wireless USB interface

I have been developing code for this open source flight controller, and the one thing that I would like to improve with my workflow is to be able to flash the firmware wirelessly. I am able to ...
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0answers
33 views

MIPI RFFE software implementation

I'm currently trying to implement the MIPI RFFE (As master) protocol on a simple AVR microcontroller, the specs says that the clock frequency can go down to 32 kHz, so I guess this it should be ...
2
votes
4answers
108 views

“If an antenna can transmit, it can usually receive as just as well”

Scenarios So, I set up an induction loop, just a simple single wire loop around a house with a little pickup coil for picking up the loop audio. Lets say I want to run this in REVERSE I have heard ...
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0answers
22 views

Which Communication technology to use? [duplicate]

I want to create a network of transreceivers which are able to send data to one base station these transreceivers should also have support unique ID the range should be around 5KM power no issue but ...
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1answer
70 views

Cloning Keeloq remote keyless entry system

Our house and a few other share the same gate, which is opened remotely by a 433Mhz transmitter. Unfortunately, we only get one remote per house, and we have two car. The company operating the gate ...
0
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1answer
58 views

Using filters to reduce bandwidth of received signal

I am doing some radio work, and I assume you can use a bandpass filter to reduce the bandwidth of a received signal. The application is modifying schematics for a FM broadcast receiver to a 5-25 kHz ...