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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Non-line-of-sight distance approximation between trasmitter and receiver

I have one stationary object in a 2d plane (no z-axis). Let's say this stationary sphere is in the middle of a rectangular plane. I have another object in the same rectangular plane that is in motion ...
1
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2answers
29 views

Antenna mounting question

Here is the datasheet and drawing of the antenna on this link I need to stick out the antenna from a thick metal enclosure, how much of the antenna should stick out? Is it 19 mm (the black rubber ...
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1answer
37 views

Using of RF transcieivers to communicate over 230VAC powerline

Initially I need to communicate between several devices placed within one appartment (or a building). All those devices will be connected to 230 VAC power line. I'd like to skip any wireless ...
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1answer
52 views

How deep can I bury a 1 MHz transmitter

So in designing a deep underground sensor network, my team wants to use a 1 MHz radio, but we cannot determine a way to model the soil, so as to calculate how deep i can bury a radio for showing proof ...
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1answer
42 views

how to make an rf choke ? & tx rx coils

i am an tinkerer and trying to make an wireless charger in which i felt difficulty in making an RF choke coil of 8.6uH , 0.674uH & 1.235uH so any can please help me out ...
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21 views

Does higher clock speed equate to higher resolution of distance measurement using RF?

I am trying to create a simple measurement system using RF but have found only devices that have fairly large windows of accuracy (+/- 1ft is the best one I've found yet). If I want to measure the ...
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30 views

What are Cadmiium fractions exactly? [closed]

Hello StackExchange Community, I'm working on a mini Introduction to engineering Assignment and I'm having a lot of trouble searching for something I been looking for three hours now and have no luck ...
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0answers
42 views

How many cell phone can one put in 1 cubic meter without interference for gsm and or gprs network? [closed]

I read the answer to the question "How come radio signals don't interfere with each other all the time?" and I was wondering how many cell phone can one put in a cubic meter without having them ...
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2answers
64 views

Electronic compass, RF and batteries

I am currently working with a project where i am creating a small embedded board consisting of a 9DoF IMU which is transmitting its data with RF (BLE or normal RF). Furthermore there will be a battery ...
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2answers
97 views

How can I best fake an (AM radio) antenna signal?

I have an old (~late 1920s) AM radio that I'm currently working on. As I don't want to modify any of the internals significantly, it would be nice to have a way to fake antenna input. It's not ...
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1answer
55 views

receiving transmissions transmitted on different channels sub-1 GHz using one receiver

I am using a RF development board along with a CC1120 RF modulator + CC1190 amplifier on carrier frequency 868MHz, RX filter bandwidth 25KHz, modulation format 2-FSK, 1.2Kbps bit rate, 10dBm output ...
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23 views

Achieving multiple transmissions at the same time within a Sub-1 node network

I am using a RF development board along with a CC1120 RF modulator + CC1190 amplifier on carrier frequency 868MHz, RX filter bandwidth 25KHz, modulation format 2-FSK, 1.2Kbps bit rate, 10dBm output ...
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19 views

RF Propagation of a beacon placed in a narrow hallway

If the walls are sufficiently thick concrete which have very high attenuation, and if the red circle is a beacon/ibeacon with an omni antenna, what is the expected propagation pattern? I want to ...
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1answer
22 views

Microstrip lenght problem

I'm simulating a single microstrip half-wave resonator (1.8 GHz) in Sonnet and using ADS LineCalc tool for calculating the microstrip length but I'm getting a wrong number. Substrate parameters ...
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2answers
35 views

Will an impedance matching network also act as a filter?

Will a matching impedance network also act as a filter? I'm using a pi network and am wondering if I should also add a filter. I designed the pi network by using the program SimSmith and it consists ...
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2answers
45 views

Band Pass Filters for MHz

I have come across the following site: Passive Band Pass Filter - Electronics Tutorials. It is a tutorial about band passive filter circuits. The following formular is given with: $$ C=\frac{1}{2 ...
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0answers
45 views

Lc tank resonator vs. quartz crystal?

For Colpitts and Hartley oscillators, which is preferable to use: an lc tank resonator, or a quartz crystal? I've built Colpitts oscillators with both an lc tank circuit resonator, and with a quartz ...
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58 views

tunable oscillator circuit: get rid of the variable capacitor

In these days I'm doing some experiments with oscillators circuits; I've built an oscillator circuit which is tunable using a variable capacitor (the range in picofarad of this variable capacitor is ...
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1answer
57 views

How to convert this FM transmitter to receiver?

I made this circuit and it works properly but I need to make an FM receiver using the same idea of this circuit (common base). Would you tell me what changes should I make so that the circuit is able ...
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7answers
791 views

Is the meaning of a Decibel different when applied to Voltage vs Watts?

If I have an amplifier that provides +3dB, or an attenuator that provides -20dB, then how do I know if that applies to Voltage or power? In other words, if I have a 0dBV signal and I run it though a ...
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2answers
45 views

Circuit board layout: wifi ceramic antenna next to a electromechanical relay

Is it okay to place a small ceramic antenna not far from a electromechanical relay? Would the magnetic field generated by the relay coil (when on) affect wifi operation? clarifying edit: not far = ~1 ...
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1answer
63 views

Boost a weak AM transmitter

I've made this simple AM transmitter: http://makerf.com/posts/fun_with_crystal_oscillators_part_3 The author of this circuit, claims that would be possible to extend the range of this transmitter ...
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2answers
61 views

Design options for a simple AVR (Arduino) based RF communication system

I am trying to build an AVR based, RF service calling system. It works like this: someone at the transmitter presses a button and the guy at the receiver get notified with the ID of the transmitter ...
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28 views

occupant sensor/detector for goods vehicles - active during driving

I need to detect and raise an alarm in the goods load area of a consumer goods vehicle if there is human movement detected whilst the vehicle is in motion. To put it simply - our goods vehicles are ...
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1answer
22 views

wireless sensor baud rate calculation

I need to calculate baud rate of wireless sensor which operates on 433.92Mhz and uses OOK modulation. Signal wave form and packet structure are known. Packet = 36bit (44.7ms), each bit consists of 2 ...
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1answer
52 views

Calculating expected receive power

I am using a TI CC1120 + CC1190 combination to transmit data wirelessly using Sub 1 GHz link. My output power is about 27dBm according to the CC1190 SOC. I want to determine the maximum power (an ...
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5 views

How to add Marker (Event) to a bitstream file in Agielnt MXG Signal Generator?

Using an Agilent N5182B MXG Vector Signal Generator in the Dual ARB mode I am able to create, download and play a baseband waveform with the samples' marker #1 set, and sensed via the ...
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75 views

Pic to Pic Communication with 434mhz wireless module?

I want to transmit Data From one Pic18f2550 to Another using a cheap 434mhz wireless module. but its not working at all. Following are the circuits for Tx and Rx respectively. the code for Tx ...
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1answer
40 views

Will a CC1120 IC be burnt during transmission if antenna is removed

I am using a TI CC1120 evaluation kit which is working in the 800MHz band amplified by a C1190 to a 27dBm output power. I would like to know if it would damage the board to be used with no antenna ...
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1answer
72 views

Why are shorter leads preferred over longer leads?

I'm building oscillator circuits on a copper plate for an RF design class using the dead-bug method. I know that short leads between components is preferred over long leads, but why is this? I heard ...
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1answer
55 views

How do I find spectral purity?

How is spectral purity measured? or evaluated? I have this signal coming from a 10 MHz crystal oscillator. I know how to calculate the SNR, but how do I calculate the spectral purity? Is it also a ...
2
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2answers
275 views

Why does a metal sheet block all noise, but not when wrapped around a cable?

If I place a flat sheet of aluminum foil between a near-field probe and a noisy wire, the sheet completely blocks the noise. However, if that sheet is then wrapped around the wire, it seems to have no ...
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0answers
36 views

Weather Balloon Wireless Mesh Networking

I am trying to get real-time data feed from a homemade weather balloon radiosonde with the objective of sending HD video during the flight; this could be relevant for GoPro-ers who want to send their ...
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38 views

What's google's balloon estimated LTE radiated power at ground ?

Google loon, google's internet balloon project , is transmitting from a height of 20km , and has a cell radius of 40km, and uses LTE. What would be the EIRP ? would be one such that EIRP at near ...
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1answer
50 views

Wide band vs Narrow band communication [closed]

When using the RF what is the difference of Wide band and Narrow band communication? Most ICs claim to use Narrow band and I have not come across ICs that use wide band communication. Is there a ...
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2answers
48 views

Protocol design in a steel conductor

I was wondering what energy efficient protocol should I use for a FSK modulation in a steel conductor. My limitation is on the number of continuous bits I can transmit due to the charging and ...
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1answer
77 views

Characterization of Power Harvester

I have chosen a power harvester to power a few things as part of a wireless system. This one is the one I have and it seems to be operational: http://www.powercastco.com/PDF/P2110-datasheet.pdf ...
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16 views

6LoWPAN deployment in an MCU

I need design a 6LoWPAN supported node using a TI CC1120 controlled by a TI ARM Cortex M4 TIVA 123 Lanchpad. I require to run TCP, IPV6 along with 6LoWPAN in the Lanchpad connected to the CC1120. I ...
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1answer
73 views

Why deliberately mismatch impedances in RF?

My professor wants me to design a cascaded RF amplifier, with mismatched stages. The reasoning is to increase bandwidth. Is this correct? If so, can anyone elaborate on the theory why mismatching ...
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1answer
76 views

Why don't we use cascoding in RF amplifiers?

I need to design an RF amplifier with high gain. It seems every RF book teaches cascading, but not cascoding. Is there a disadvantage to cascoding? It seems like we don't need to match impedances with ...
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1answer
123 views

How to conduct “Transient Power” measurement according to ETSI EN 300 220-1 (v2.4.1)?

Background Info The company I work for builds Active RFID hardware that needs to conform to the regulations defined in ETSI EN 300 220 (Part 1). Our working frequency is 433.92 MHz. I am responsible ...
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2answers
65 views

Hartley Oscillator Alternate Oscillation Mode

I've been trying to build a hartley oscillator and have almost succeeded, however my calculations are off by appx 1000 relative to the measured waveform. AND the kicker is that it only works when I ...
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0answers
22 views

IEEE 802.15.4 standerd

According to Wikipedia the said standard defines physical layer and media access control (MAC) control for devices working in the Sub-1 range. However I noted that this standard is not similar to ...
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0answers
43 views

Colpitts vs. Hartley?

What are the pros and cons of using a Colpitts or a Hartley configuration for an oscillator?I know that the difference between them is the form of feedback, but does one or the other perform better ...
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0answers
23 views

How to measure the QoS of an anlog wireless link

I am working with FSK transmitter and modulator on the 433 MHz band, I am wondering how can I measure the QoS of the resultant link given that The receiver reports the received analog data only with ...
0
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1answer
62 views

2.4GHz Bluetooth PCB Trace Antenna Range

I have designed a PCB trace antenna for a BLE module. I used an existing reference design, which is offered to be used in your own design. I am able to connect to the radio, and on a spectrum analyzer ...
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3answers
56 views

Efficiency of Antennas vs operating frequency

I have refereed a document from TI which mentions that antenna efficiency decreases as frequency is further decreased. Although 136 - 240 MHz has highest range for equal power, the efficiency of ...
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3answers
92 views

Sending data from 4 transmitters to 1 receiver without a microcontroller

I am working on a project to wirelessly check whether any of four switches are pressed and I don't want to use a microcontroller on the transmitter side. I have worked with the cheap 434MHz HT12E/D ...
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3answers
264 views

Frequency spacing and the doppler effect

Suppose that I'm working on a system which needs to use a transceiver with an FM signal. If that system moves very fast (i.e. it is a satellite or whatever) in which the maximum doppler effect can be ...
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2answers
41 views

Uneven (10 dB) RF Power Splitter/Combiner

I'm trying to modifying and improve the MIT radar project Here's the basic block diagram: Input power is split by 3 dB SPLTR1 to transmitting antenna and LO input to the mixer. From what I ...