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.

learn more… | top users | synonyms (1)

0
votes
1answer
41 views

How does Android able to communicate with IO Circuits [on hold]

How does Android for mobile devices actually able to communicate with IO such as the integrated modem circuit built into the latest Qualcomm Snapdragon ARM core IC's ? Would it be through the CPU via ...
2
votes
1answer
281 views

simplest FM radio receiver?

As per this building simple radio it is the simplest AM radio receiver. obviously this is very poor AM receiver.(but it was working for someone in comment) I'm wondering what will happen when ...
0
votes
2answers
52 views

Can a COTS FM Radio transmit?

This is probably a really silly question, but I still want to know... Given a standard off-the-shelf FM radio alarm clock, what is to stop it from transmitting radio waves when physical motion causes ...
0
votes
1answer
46 views

Remotely (long-distance) triggering a 12V solenoid?

I have purchased a "1CH DC12V 2000M Long Range RF Remote Controller Kit" - this is a remote relay. With this gear, I have to power both the receiver and the load with 12V sources. I'm trying to ...
0
votes
2answers
367 views

How to measure EMI without special equipment?

I have bought a cheap dashcam to play with, only to discover that my GPS receiver stops working when it's on. After I ruled out power supply issues (both devices have batteries), I'm left with a ...
3
votes
0answers
43 views

Blocking RF on same side as PCB antenna?

I have a penta-band GSM transciever on a 4-layer board, along with a matched chip antenna. Similar concept to ...
0
votes
2answers
60 views

What is load on an antenna? Is it safe to short the antenna port?

On the readme page of https://github.com/pwarren/rtl-entropy, it says: If you're serious about the cryptographic security of your entropy source, you should probably short, or put a 50 Ohm load ...
-3
votes
1answer
46 views

RF Transceivers [on hold]

I just need to send signal pulses with different duty cycle from RF transmitters of same frequency to a single RF receiver. How to differentiate the pulses from each transmitter?? Can anyone help me.. ...
0
votes
0answers
24 views

How detect activation loop from AMB / Mylaps transponder

I have a kart track with AMB transponder TRANX 140 and TRANX 3 decoder, That transponders has a small battery with 5 years duration, so i guess they are activated by loop just few millisecons and ...
5
votes
1answer
45 views

Placement of two independent crystals

This one is completely about PCB layout. I have two 26MHz crystals in the design, one for each processor on the board (TXC 7M-26.000MEEQ-T, datasheet: ...
-3
votes
0answers
12 views

SM5172 RF encoder replacement [closed]

I searching the IC SM5172-L3, it's a RF Encoder where it was located in wireless remote control. I can't find it nowhere! Is there some other which can replace it?
0
votes
0answers
33 views

Xbee pro 900 MHz long range just reach 950m

Thanks for your time. I´m developing a communication system that need to reach 1.3km to carrier water to a native community in Colombia. I´m using the Xbee pro 900 ...
0
votes
0answers
20 views

More traffic decreases the signal strength [closed]

Why the higher/more traffic that travels through the Access point, will decrease the signal strength of the access point? is there any invers relationships between them ? what is the theory ?
0
votes
1answer
40 views

Is it possible to multiplex the same frequency (without bandwidth division)?

I have a range of bandwidth (e.g. [865,868] MHz) and more than one RFID tag I'd like to receive information from, over that range. How could I multiplex those ...
1
vote
1answer
44 views

Retrofit a Hi-Fi remote with a RF 433 MHz module

In the past I used a remote for a AIWA Hi-Fi to control a AVR processor and circuit I custom made. I used an infrared receiver from Vishay (tuned on the 38 kHz) to demodulate the signal, then fed to ...
1
vote
2answers
59 views

Royer Oscillator

Hello everyone and thanks for your time reading this. I recently switch my oscillator circuit over to a digital based version. With this topology I can monitor source currents on each RF MOSFETs ...
0
votes
2answers
97 views

What are the differences between function generator and oscillator? (Specific design)

I design the attached circuit: 75 MHz Sine wave that connected to R and C in parallel: In the output, the amplitude of the sine wave is changing according to the C, more capacitance smaller ...
0
votes
1answer
47 views

What free software can be used to simulate transmission lines and other RF circuits? [closed]

Technically, one can use LTSpice as it features a transmission line model, but obviously it doesn't like dangling nodes (ie. open lines) and isn't really suited for that purpose anyway due to lack of ...
0
votes
2answers
33 views

Increasing loss of cables to attain dynamic range

RF newbie here. Trying to learn about cables and losses and how they contribute to dynamic range. I'm creating a shielding effectiveness system for enclosures with a 120dB dynamic range using signal ...
3
votes
1answer
79 views

Would you explain the output waveform of this FM transmitter circuit?

I build this circuit and it works. I wanted to look at the output waveform by my soundcard oscilloscope software. I would expect something like the following picture: But the output waveform was ...
1
vote
0answers
54 views

What signal loss can I expect by routing a 20 dBm 900MHz signal in a 90° curve in a PCB?

I would like to change a PCB to add a (not straight angle) 90° curve in a 900MHz signal path. From my understanding my PCB designer is simply using the correct impedance, routing the signal on the ...
0
votes
1answer
36 views

Shielding effectiveness system

I've been working on a Shielding Effectiveness system of 120dB according to IEEE299-2006 standards. The frequency range covered is 9kHz to 40GHz. I've designed it using an analog signal generator, ...
0
votes
1answer
38 views

Unnatural AD9850 Output Attenuation

Yes, another question about this DDS. However, I think mine is sufficiently different from the others I've read. I purchased an AD9850 board on Amazon for $17 from "NooElec" (see here). I've been ...
6
votes
1answer
68 views

Can I solder a RG316 coax directly to a PCB instead of using the intended SMA connectors?

I have a length of RG-316 single shield 50Ω coaxial cable carrying a 5.8 GHz signal that I need to connect to a PCB. While cheap relative to most coaxial connectors, SMA connectors are still quite ...
0
votes
1answer
46 views

RF cable with DC power cable?

I have a satellite communication system at office running on C-band. The C-band is downconverted to L-band and carried to the l-band modem. With this RF coaxial waveguide/cable, +12V DC power cable ...
-1
votes
0answers
39 views

TV Demodulator and TV Tuner

I was wondering what is the difference between a TV Demodulator and a TV Tuner. When I google TV Demodulator, things like Olson OTD-3000 shows up as opposed to googling TV tuner which either shows ...
0
votes
1answer
41 views

How can I amplify 868MHz transmission done with a wire antenna?

My garage door is sending its status to a control device we have in the house. This signal is not always received by the control unit so it wrongly shows the garage door is open when it's closed. The ...
1
vote
1answer
62 views

My first RF Transmitter Circuit

I'm in the process of creating my first 433mhz RF transmitter with a PT2622 encoder & SAW Resonator. I included a portion of my schematic below that shows my PT2622. Does my schematic look ...
0
votes
1answer
111 views

Are RF shields necessary?

I see that some wireless devices like Bluetooth speakers don't use shields like this one but some do. My understanding of FCC Part 15 is that only modules need shields. So how come some devices use ...
0
votes
2answers
55 views

What does SMA Tee Adapter do?

SMA tee connector is something like this: What does it do? Is it something like a power divider?
1
vote
1answer
52 views

SPI Read Function of STM8S

I am converting arduino-nrf905 library for stm8s. There is one spi function on the arduino library, it is SPI.Transfer(uint8_t reg). This function can write and read spi. But, there is two function on ...
0
votes
5answers
82 views

Will the data throughput decrease if the transmitter and receiver are in motion?

What I'm thinking of is a 2 way communication (voice communication) between two systems which are in motion. (like 100 km/h difference) Will the data transmission and reception be disturbed, by how ...
0
votes
2answers
29 views

Transceiver and RF Emissions (Unintentional)

My question is simply what is RF emissions (unintentional) and how does it relate to a device (such as a smart phone) which contains a transceiver or transmitter (baseband IC) ? Which part of a RF ...
1
vote
0answers
26 views

Compressed single-sideband modulation?

I've had an idea for a new form of SSB modulation, using half-angle formulas as a basis for compressing the sideband of a SSB voice transmission. However, this idea seems so simple that I feel it must ...
3
votes
2answers
74 views

How “pinless” moisture meters work?

I see that there are "pinless" moisture meters on the market, e.g., http://www.omega.com/pptst/HHMM257.html that look like this My understanding is that they measure the amount of reflected RF. ...
2
votes
7answers
109 views

No batteries power method (induction, motion, heat etc)

I am using an ATtiny85 to sleep for a long period of time, collect some data, send it over radio, and go back to sleep, after disabling everything possible. The ATtiny is currently powered by a coin ...
0
votes
1answer
44 views

Expanded standard deviation in logarithmic scale [closed]

Hello and good day to all. Referring to picture attached I have a question. . I am working on different measurements and trying to find the mean and standard deviation values of these ...
1
vote
1answer
44 views

What is “ripple bandwidth” in filter terminology?

I'm told "ripple bandwidth" is different from a "-3dB bandwidth" or corner frequency. How is this commonly defined, and how do I derive it? My application: There seems to be a discrepancy in the way ...
0
votes
0answers
42 views

How can I convert Mentum Planet .pln (or .msi) file to SPLAT! .az and .el format?

I'm trying to split and convert a single Antenna Radiation Pattern definition file in .pln format (Mentum Planet) into a couple of SPLAT! .az (Azimuth Radiation pattern) and a .el (Elevation radiation ...
0
votes
0answers
47 views

Stanley garage door

i've an old Stanley garage door remote that is giving is last breath, i want to make a new one so i can put it in those "extra buttons" in my car dashboard but i can't find the datasheet for the IC on ...
3
votes
1answer
80 views

FCC's allowable margin of error

Below is taken from the test report for FCC Part 15 for a Bluetooth module: The heading says "2402Mhz", but the marker shows 2401.9772MHz. It's 23kHz off. However, does FCC permit this kind of ...
2
votes
2answers
41 views

Affordable way to test frequency range of a 2.4GHz device [closed]

Does anyone know of a good/affordable way to test the frequency range of a RF device (e.g., Bluetooth module)? Not spectrum analysers since they're rather unaffordable. Are there relatively affordable ...
1
vote
0answers
68 views

Detecting the distance of my dog to the food bowl

When one of my dogs sneaks to another dog's food bowl, I want to be notified so I can stop it. I have EZ430-RF2500 (msp430) development kit. Is it suitable for such project? I also have Arduino so I ...
3
votes
3answers
82 views

How can I wirelessly deliver ~30B of data to ~10 peripherals roughly every 50ms?

I am thinking of a system where 10 or so peripherals need to receive 30-50B of data every 50-ish milliseconds (each peripheral gets unique data). The total throughput required might not be huge ...
0
votes
0answers
54 views

Calculating mean and standard deviation of Power values

My question is related to measurements in communication field. I have done some measurements using spectrum analyzer. I did repeative measurements and got 10 values in dBuV/m. Now I want to calculate ...
1
vote
1answer
35 views

GSM/GPRS reach for Class 4 2W 900MHz/ Class 1 1W 1800Mhz

I'm studying differents GSM/GPRS modules and all of them have two operation modes depending the frecuency (900MHz and 1800Mhz). If I'm not wrong, for the same power higher frecuencies have a lower ...
0
votes
0answers
54 views

Effect of copper thickness in PCB antenna design

I have been going through TI's design note DN0007 recently which describes the inverted F antenna design supposed to be used with 2.4 GHz systems. This is the antenna I am talking about: Design ...
3
votes
2answers
45 views

Do I need coupling capacitors with this balun?

I'm connecting an antenna to Atmel's SAMR21 microcontroller and the datasheet provides this guidance: I've found 2450BL15B100E, an SMD balun, but I'm not sure if it actually contains a transformer, ...
1
vote
5answers
141 views

Blocking DC without blocking any frequencies?

Is there any practical way of blocking DC without blocking any AC frequencies (or as few as possible)? Suppose I wanted to block DC and let through all frequencies between 2Hz and 10Ghz with minimum ...
3
votes
1answer
72 views

How to automatically switch RF path to external antenna

I'm designing a circuit that has 2 antenna options for one transceiver @ 1.6 GHz. One antenna is internal and is the default RF load. Another antenna is external - to be attached by the user if ...