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I don't have any formal education whatsoever but I've been trying to teach myself EE for a few years now, and over the last year and a half I've focused on RF EE and I think I might be ready for a internship soon. I don't know a good way to know for sure if I am though so I wanted to get some type of certification to kind of prove to myself, and an employer that I have what it takes to at least help around in some way. I first looked into the FE exam but they require some form of schooling so is there a credible certification I can get that can help me in finding an internship, and then job later on. I've looked into the CWNP, but I don't know if there is a better one for me. Also is there a test out there that I can do online to determine if I'm ready to get into this professionally? I think I have the theoretical knowledge down, I'm just teaching myself the math a little more. I am going to be 21 in a few months, and I would prefer a payed internship even if it's the low end of their asking on the listing because of my lack of certification. I am in California and close enough to commute to silicone valley luckily so location shouldn't be an issue I don't think, but some insight would be nice thank you.

Is it possible to improve the input/output return loss of internally matched components?
I would think the best you could do is shift a more favorable match at some passband to where you want it.

The international adaptation seems to be similar to the 4th edition but cheaper and available in physical copy.

Is there an actual difference between the two ?

If the following statements are all true:

• Antennas designed for a particular frequency have a reflection coefficient that changes as you move away from the centre freq, to a maximum of 1.

• The reflection coefficient at any frequency can be measured with a VNA.

• Given the reflection coefficient of a system, we can calculate input impedance and design a matching circuit to Z0.

Then why do we consider frequency when designing the antenna at all? Why does the antenna design process starts by calculating the relevant half / quarter wavelength, and then matching impedance afterwards? Why can’t we just take any piece of conductor, impedance match it to Z0, and have a perfectly good antenna?

Of course it makes sense that the antenna element has to support resonance at the centre frequency, but I can’t conciliate that with the above statements. What am I missing?

Edit: Okay I realised why approximately a minute after posting. The difference is how the energy is dissipated after the impedance is matched. A properly tuned antenna dissipates almost all the energy into free space. An incorrectly tuned antenna can also dissipate all the input energy if properly matched, but it will dissipate most of it as heat in the resistance of the conductor. This is the step I was missing, a subtlety never covered in lectures.

I have a A300 power supply ENI and I can't get more than 9 watts at the Driver output. I have changed all the transistors and some resistor's value to obtain the emitter voltages, but still nothing happens. I appreciate any help.

I am characterizing a programmable attenuator with a VNA checking it’s set attenuation vs measured across a frequency range. The attenuator goes from 0-95dB.

I’ve calibrated the VNA and have set a program up to capture the trace data. Measuring in 2MHz steps of a 100MHz BW at 2.4GHz Wi-Fi frequency.

At the low range of the attenuator(95dB) I am seeing up to 8dB swings and even in a 2MHz step can see 6dB.

Wondering if I am missing anything or this is just the performance of the attenuator/cable. I am using pretty high quality VNA cables(gore) but not sure if I need even better cables? Typical accuracy for this configuration is +-3dB up to 4dB max.

Hi All,

Im new here and not acquainted with the etiquette in this specific subreddit so apologies if this is not the right place for this.

Im considering purchasing a flat on the top floor of a building in the UK. The apartment is amazing, however it has these antennae next to it, right next to the roof terrace and also within about 3 to 5 meters which is about 15 feet from the bed in the primary bedroom.

I am not personally worried, other than the aesthetic aspect, however I have been unable to find proper studies by a european government body or entity to confirm these are not harmful for the health. Could anyone point me in the right direction here?

I understand the RF are non ionising, but could anyone point me in the direction of one of these studies to give comfort to my family who are understandibly slightly tentative.

I have attached photos of the array of antenna and also a list of the equiptment which I have also been unable to find on google. The photos of the antennas was taken from a different terrace.

Id appreciate any help, especially from people who know what they are talking about =)

https://preview.redd.it/03d8er8iby0d1.png?width=1011&format=png&auto=webp&s=2539d86de2fb2ec78f03a30ee49c14980b9c0c43

taken from different roof terrace

Taken from a different roof terrace. The apartment in question is just behind the array.

I'm currently working on the design of a multiband circular patch antenna , and i am having a problem with the radiation pattern . Specifically , i've noticed that there is directivity ,but the gain values i am getting are negative ( in dB) . I was expecting to get positive gain , but i am puzzled as to why they are negative. Can anyone help me understand why the gain values are negative and how n i solve this problem ?

I know I sound like a kook, but can someone please explain if the RF or microwave or whatever is emitted from baby monitors (a plug-in, DECT, and sound only version) is harmful?

I have had them plugged in near my children’s cribs and am worried I gave them a brain tumor. I came across this site that spooked me: https://buildingbiologyinstitute.org/wp-content/uploads/2019/05/Baby-Monitors-Fact-Sheet.pdf

Hello, I am working on an RF project where I want to generate a pulsed signal. I am noticing when I try making the duty cycle smaller and smaller I am running into issues with a lot of noise in the background. I have done a bit of digging and I am wondering if this has something to do with "ringing" but I am not sure. If anyone can help me figure out what is causing this and what I can do to fix it that would be greatly appreciated.

Here is on/off of 1ms

https://preview.redd.it/5gkegyajbv0d1.png?width=1311&format=png&auto=webp&s=f7282ad723f1424d31281ba02670c696d06480c1

Here is on/off of 100us

https://preview.redd.it/191egaptbv0d1.png?width=1310&format=png&auto=webp&s=8cfe60a198208466cf5830f01b6d426bc6661b64

Here is on/off of 10us

https://preview.redd.it/pg4cypk3cv0d1.png?width=1309&format=png&auto=webp&s=914bf708dd705d57e14f2ce694e3043859acc708

I am using the HMC321ALP4E for toggling the output and an stm32 for controlling it.

Hey all, i've been working on designing a board that uses an NRF52840 for 2.4ghz communication and it needs to have a directional antenna. I've chosen a moxon as it seems to have a good balance between FOV and higher gain. Because it's a pcb antenna, i checked my fab's stackup and for a 50ohm trace they recommend 0.035mm x 0.167mm and i've converted that to an equivalent circular cross section (0.0431r). I then used MoxGen to get the dimensions and then simulated that it should work well with 4nec2.

My confusion lies in that something with the antenna just, feels off to me? The traces are very thin which i dont see in other pcb moxon antenna products and i also feel like i'm feeding it wrong? Having a trace run underneath the reflector and then connect with a via seems like it would cause issues.

Is my design actually wrong? Or should I just trust the simulations that it will work well?

MoxGen screengrab

4nec2 Simulation

PCB Design

Hello there, I've been thinking of building an short range( below 25m ) , live audio streaming from an microphone to and receiver block near, I have prior experience in embedded systems, but I'm not sure about the complexity and approach towards this project, I've tried googling some RF SOC's for this, they come in all shapes and size, I would like to get some insights on this topic, there aren't many projects online over this topic. I don't want an hi-fi system, but more like a hobby project with standard audio quality, please give your insights to this. Thanks

I'm not an RF engineer so if I sound like a "differently abled" person please cut me 2M of slack. :)

For debugging Wi-Fi interference issues I have an idea for using a directional antenna to take a narrow slice (1-2°) of the RF activity in a given direction. I would then using a stepper traverse the antenna and take additional slices. These slices could then be stitched together to produce a "photo" of the RF sources in a given area.

My questions are:

1. Does such an antenna - for lack of a better term a "narrow aperture" device - exist or could be fabricated?
2. Is there a reasonably straight forward way to feed this information into something like a Raspberry PI?

If anyone could point me in the right direction, I'm willing to study and learn what is necessary; as much as anything I'm just trying to judge the feasibility of this project. Thanks!

So power is radiated from the antenna in an rf circuit. If I understand things correctly, there's no (or very little at least) radiation from the feedline, since it sits tightly coupled to ground, so the waves radiated from the feedline and ground cancel each other out. But if they are radiated from the feedline (but cancelled), does that mean that that power is in fact "wasted"? Or is it somehow induced back into the system? (My rf knowledge is limited, so some terms I use might be off...)

Hi everyone,

I have been using a KeySight N9020A MXA Spectrum Analyzer to capture IQ data. In order to automate my measurements, I have been setting the equipment with a Trigger Mode that is based a RF Burst that my DUT sends and then I try to read the IQ data via SCPI commands on Python.

However, I'm having issues with this because it seems the equipment keeps on hanging when I try to read the IQ Data. This behavior is somehow intermittent. Based on what I could understand, the equipment always hangs when the screen is showing the following message: "Waiting for trigger"

https://preview.redd.it/ppg035w8tl0d1.png?width=1150&format=png&auto=webp&s=bf596b4d8b857198d9ceac9e361aa8b3b96d1cca

Now, this message takes some time (1/2 seconds maybe) to appear after the DUT transmits data. What is bugging me is that this behavior is not consistent, that is, it sometimes hangs and other times it does not. Sometimes my scripts are running just fine, and suddenly they start hanging on the read SCPI IQ read command. I noticed that if I restart the equipment, it starts working again. Has anyone else faced similar issues? Any recommendations on what to do?

Appreciate your time!

Thanks!

I'm electronics engineering student interested in RF, i finally decided to start getting my own workshop together (open lab at my university sucks). I don't really know if 150MHz more is enough of an improvement to pay so much more. I was never interested in RF before my studying so idk what i really need, also is 250MHz near enough VHF to work in it? or is 300MHz minimum?

edit: cheaper one is rigol dho804 (modded for more bandwidth) the more expensive one is rigol dho914 also modded. i can also pay about 40€ more to get included AWS but it doesn't look very useful at 25MHz sine wave and much less at other ones

edit2: Thanks everyone <3, after a lot of consideration i decided to get cheaper Rigol DHO804 and tinySA

I'm a teenager who's learning about rf engineering and I have one question which I still can't get past. According to everyone I've asked they say as you try to send more symbols per second, you must increase bandwidth to avoid interference, my one question is, if it's like a highway and if you have too many cars in one lane, they crash etc. why can't we just send rockets spaced apart equally and they'll go as fast as light ? I assume their is an obvious answer but I don't understand it,if anyone would like to message me if I'm not being clear enough I would be honored to talk to an expert in the field.

What’s the difference using a horn antenna and a dipole as a source antenna?

For example, is it okay to use one dipole as a source antenna if antenna under test is a monopole antenna?

I purchased a wireless mic off Amazon, Ulanzi AM18 (2.4GHz transmitter & receiver).

There is a safety statement regarding possible radiation.

“This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This equipment should be installed and operated with minimum distance 20cm between the radiatior & your body.”

It’s a wireless mic designed to clip onto our shirt so will be using this within 20cm of my body, can these devices emit enough radiation to cause harm?

I have been looking around for outdoor battery powered WSNs with longer range than the 902-928MHz 1W systems commonly available, but can't seem to locate any.

The frequency band of interest is around 40-41MHz or thereabouts, preferably FSK. This band sits in spectrum that would not need to be individually licensed here.

Has anyone crossed paths with such a system before?

Thanks!

This is the picture of the Radio Frequency Module they're using in an Xbox 360 E. I was trying to connect a USB A cable to it to use its controller with my PC.

Microsoft's Xbox 360 RF module

Color code of a USB-A cable

I just need help in understanding which colored wire would go on which pin on the pcb

ps. im talking about this part

https://preview.redd.it/voq58mmigb0d1.png?width=423&format=png&auto=webp&s=67bd6ceaf04ebcbb764e91c79a7e67d3f6372bc7

also, for reference this is what i came across after searching through the internet for the connection circuit with a usb cable

Circuit diagram to connect the USB cable to the RF module *ACCORDING TO ME*

I'm using an LNA to boost a signal going into an SDR. My receive levels aren't matching my link budget so I'm double checking that I'm not making bad assumptions anywhere.

Here's the LNA

https://preview.redd.it/4x7ro2ka990d1.png?width=1122&format=png&auto=webp&s=638bc928dbaf89e2397d10abca9c0f8e487473f2

It's a '50 Ohm' LNA, but when plotting the S-parameters provided by Minicircuits (and I confirmed on a VNA) there are very few frequencies that are matched exactly. Is the expectation that the user is going to provide a matching network so that there's an impedance match at the frequency being used?

Is the smith chart above normalized so that any point on the plot is close enough to 50 ohms?

Sorry if I'm missing something obvious, just trying to identify what I might be missing. Thanks!

I need to connect to Wi-Fi to download from internet, to stream through Miracast to a display (with the least latency), plus BT to pair the device with other BT devices. Would a 2x2 solution makes much difference over a 1x1?

I’m buying a bond bridge to operate my ceiling fans and I thought it would be helpful to know the FCC ID so I can get the. This little guy comes from a Chinese made tiny 22 inch ceiling fan in my theater room.

The brand of the fan is Ocioc. Model:TLYCFL03 The remote case has no FCC ID number on it and neither does the fan that I can see from the outside.

Hi, I'm looking to make a BPSK modulator for evaluating a CCSDS compliant telecommand system(PCM/PSK/FM or PM).

The data rate is upto 4kbps Sub Carrier: 8kHz / 16kHz - BPSK modulation Carrier: S Band with PM/FM. I need to generate data modulated on a bpsk sub carrier so that it can be fed to a signal generator as external source for PM/FM modulation (if there's any other way, please suggest)

I can get PCM data in diffential form, that needs to be BPSK modulated onto a sub carrier i.e., 8kHz or 16kHz. Can anyone suggest a way for this. I'm thinking to use AD633 for modulating, to generate the sub carrier I'm planning to use a crystal oscillator. Would it work? Or is there a better and simpler way?

I am designing a PA for 3.0-4.5 GHz freq, and i need to select the Chip Capacitors for stuffing on the prototype. Could anyone help me refer the high frequency chip capacitors linking to the datasheet, cause mostly I could find AVX or TDK packages which are for max 2.4GHz. Thanks

Power-up/power-down sequencer and power/bias corcuitry for some broadband Mini-Circuits amplifiers modules.

Bias/powe board was manufactured and populated by JLCPCB, while the MMIC amplifier modules were fabbed by OSHPark and populated by me.

The bias/power board works well. The amplifiers are supposed to go to 20 GHz, so I'll see how well those work when I get access to my workplace VNAs.