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Questions tagged [radiation]

While rare, this tag should be used for questions pertaining to using electronic devices (passive or active) in an ionizing radiation environment. This could be space, medical facilities or physics labs. Defense or military related questions are probably classified.

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Does anyone know the history of the SBM-20 Geiger Tube?

I know they were manufactured by the Soviets, but anything more than that I'm unsure of. I really want to know who originally designed the tube and what companies manufactured it and where it was ...
rhett a's user avatar
  • 11
0 votes
0 answers
77 views

SRAM not writing properly after radiation exposure

I have an SRAM memory device GM76C88AL with this datasheet. The RAM was exposed to a radioactive beta source (~2MeV) for some time (about 2 hours). The source was just right above it (placed on it), ...
ludicrous's user avatar
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0 votes
1 answer
76 views

Harmonics of Ethernet (100MBps) MLT-3 signals [closed]

I have EMC Issue (Radiation) as attached..where at some frequencies the emission levels are exceeding the limits.. I use 36V power and Ethernet (MLT3) for communication. These failing frequencies are ...
NICEGUY NICEGUY's user avatar
4 votes
2 answers
299 views

Can I test the EM shielding of a material with a spectrum analyzer?

I am a hobbyist and I am intersted in testing some materials for their ability of reflectance/absorbance/transmittance for microwave radiation and I want to know if a spectrum analyzer is suitable ...
Tintin's user avatar
  • 75
1 vote
1 answer
58 views

Is it possible to slow down the rise time when using the DRV8412 for PWM?

I am using a DRV8412 to drive a 36 V DC motor with 100 kHz PWM. I see a radiation issue due to sharp 100 kHz PWM to the motor. When I probe the motor current, I see current ringing at each transition ...
NICEGUY NICEGUY's user avatar
0 votes
2 answers
83 views

Testing antenna without anechoic chamber or RF foam absorber

I have to test an inset-fed microstrip antenna operating at 2.4 GHz. My objective is to measure S11 and the radiation pattern. The problem is I cannot count on an anechoic chamber or microwave ...
fraghotmailcom's user avatar
2 votes
3 answers
114 views

Why are signals reflected from an antennas dish as opposed to being absorbed?

I am trying to learn in the area of electromagnetic noise ect. I see online that a Faraday cage can work without been contected to ground (like the ones found on radio PCBs.) It sort of makes sense to ...
George kirby's user avatar
0 votes
0 answers
45 views

NE555 pulse extender for PIN photodiode radiation detector is it fast enough? And more

I've designed a circuit using a PIN photodiode for a radiation detector aimed at identifying radium in an old watch. However, I'm uncertain about its effectiveness, particularly regarding the speed of ...
Doobalo's user avatar
0 votes
1 answer
47 views

Does an aggregation of two lambda/2 dipole antennas z-axis oriented radiate towards the mentioned axis?

I'm asked whether by grouping two dipole antennas pointing towards the z-axis, they'll radiate in that direction. I'm aware each dipole alone doesn't do that thus refraction lobes in the z-axis ...
Ketterle's user avatar
0 votes
0 answers
49 views

Antennas Far field radiation pattern

I want to understand this Far field graph of an antenna generated in CST, from the picture: Is this a good radiation pattern? If yes, then how? How to explain the graph?
Trisha Das Mou's user avatar
0 votes
0 answers
67 views

Plotting the radiation pattern of a half-wave dipole antenna with a frequency of 144 MHz in MATLAB

I need to plot the radiation pattern of a half-wave dipole antenna with a frequency of 144 Mhz in MATLAB but I don't know the code, can someone please help me?
Azl's user avatar
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0 answers
125 views

Looking to solve radiated emission test issues (CISPR 11)

We did the radiated emission test as per CISPR 11 with our device similar to tablet and observations were as below When we tested with an IEC60601-1 certified adapter, many frequencies were going ...
HR86's user avatar
  • 1
0 votes
1 answer
231 views

SBM-20 Geiger-Muller tube constantly on

I have recently purchased an SBM-20 Soviet Geiger-Muller Tube, which I want to use in a Geiger Counter circuit. I powered it with a 12V to 400V DC-DC power supply, connected in series with a 5.6 ...
leo's user avatar
  • 1
3 votes
2 answers
614 views

MOSFET as a radiation detector

We are making a thesis where we use MOSFETs as an alternative radiation detector. So to explain it, it works when the MOSFET is irradiated with an external radiation source; its voltage threshold ...
Lazy Hotdog's user avatar
2 votes
1 answer
139 views

Is it possible to connect an antenna of the proper length to a CPU and radiate its 4 GHz oscillating current?

Since a 4 GHz CPU has been made to provide that super high frequency, is it possible to connect an antenna of the right length to it and radiate its 4 GHz oscillating current?
ghd's user avatar
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2 votes
0 answers
117 views

IR LED Safety: Where does this OSRAM App note (AN090) formula come from?

The formula is from OSRAM application note AN090 "Eye safety of IREDs used in lamp applications": $$ L_{ir} \approx \frac{I_e R(\lambda)}{Z^2} $$ In the app note, they don't give a reference ...
InTheWorks's user avatar
5 votes
2 answers
487 views

Radiation tolerance of MCUs

I'm working on a cubesat project intended to operate in low earth orbit. We're considering a few different options for our flight computer, ranging from Raspberry Pi to something like STM32L476. ...
crossroad's user avatar
  • 1,430
0 votes
1 answer
236 views

FCC certification for different products with the same antenna design

I was reading about FCC intentional radiation certification and am confused about a scenario. Let's say I have two products - Product A and product B. Say I get FCC certification (for the wireless ...
vkbb's user avatar
  • 21
1 vote
2 answers
398 views

How is the frequency in the label behind microwave ovens determined? How could one measure the frequency?

It is very common online for people on youtube, forums, and other social media to bring up the following fun home experiment to "measure the speed of light" using chocolate and a microwave ...
Maximal Ideal's user avatar
1 vote
0 answers
133 views

Will 500 THz frequency glow antenna while radiating?

I read 700 nm wavelength is visible light, for which frequency is 429 THz. If we produce that frequency, whether antenna will be radiating visible light? Correct me if wrong.
E2.0's user avatar
  • 23
0 votes
2 answers
1k views

Half power beamwidth of antenna

I was solving a problem regarding HPBW. From what I understood, HPBW of antenna is the angular separation on the beam where the radiation intensity is half of its maximum value. That means U(radiation ...
user305532's user avatar
1 vote
1 answer
149 views

How do PCB trace antennas with pigtail sockets work?

I am trying to understand the general way how wireless devices (cell modem, wifi card, router, other) work that have a socket for an optional external antenna. The main goal is to increase signal ...
Boris's user avatar
  • 13
-1 votes
1 answer
222 views

How or why are powerful but low-frequency radio waves, such as from a radio station or cell tower, potentially dangerous? [closed]

Cell towers / base stations and such are limited in the power they are allowed use, even if the wavelengths of radiation used do not adversely affect people or animals. I have heard (and read) that it ...
Kurt Hikes's user avatar
2 votes
1 answer
84 views

Why are there two different charges on a patch antenna? How are these charge distributions formed?

If we apply an AC signal to a capacitor, we can see only one type of charge on an individual plate. If we apply an AC signal to a patch antenna, there are two different charge distributions on the ...
Mrunal Shinde's user avatar
1 vote
1 answer
589 views

Why are patch antennas used instead of planar dipole antennas?

As far as I know, the major advantage of patch antenna over dipole antenna is its directivity. If the planar dipole antenna can achieve the same directivity then why do we use patch antennas? Are ...
Mrunal Shinde's user avatar
3 votes
1 answer
602 views

How does selecting a higher permittivity substrate in patch antenna reduce its size?

By selecting a higher permittivity substrate do we reduce the height of the antenna or we reduce the length of the patch antenna? We cannot reduce the length of the antenna as it is dependent on the ...
Mrunal Shinde's user avatar
1 vote
2 answers
146 views

IR LED Safety: Subtend Angle and Retinal Exposure Limit

The relevant formulas from OSRAM AN090 "Eye safety of IREDs used in lamp applications" with slight modifications : $$ Z = (l + w)/2 $$ $$ \alpha = Z/d $$ $$ L_{ir} \approx \frac{I_e R(\...
InTheWorks's user avatar
0 votes
2 answers
360 views

Can a LC circuit generate frequencies in the Gigahertz range or higher?

For instance, if you took a bunch of off the shelf capacitors and arranged them in series and a bunch of inductors and arranged them in parallel, could you make the resonant frequency of the LC ...
user11937382's user avatar
0 votes
1 answer
117 views

Does a DC power supply 24V 6A that functions as a motor for a standing desk produce radiation that might be harmful?

Just curious to know if there's any radiation coming from it that can be harmful if we stay close. Thanks.
Raaas's user avatar
  • 71
0 votes
1 answer
181 views

Microwave Turntable Absorption

Do microwaves turntables absorb some microwave radiation when being used? I heard that they can act as a minimum load on the magnetron. If this is true, can I interchange microwave turntables? Edit: ...
Steve's user avatar
  • 80
4 votes
2 answers
2k views

How do I find out the dimensions of a rectangular waveguide given the frequency I want to operate it at?

I want to design a horn antenna to detect the 21 cm hydrogen line. I know how to optimize the antenna dimensions by taking into account some functions that approximate the phase errors and ...
requiemman's user avatar
2 votes
0 answers
90 views

Why have space-grade components such long leads? [duplicate]

What are the reasons why (some) space-grade components are shaped like they are, with their characteristic long flat leads, golden finish, etc.? Image: DP83561-SP from TI Are the assembly houses ...
Harnex's user avatar
  • 166
2 votes
2 answers
567 views

Antenna radiation plot and negative gain values

In general, how to interpret the negative gain values on antenna radiation diagram plot? I have attached an example. My guess is that they represent some value relative to some reference value. If so, ...
Quirik's user avatar
  • 287
1 vote
2 answers
85 views

How to increase efficiency of antenna without moving antenna far from tree?

I have designed a monopole antenna at 868MHz frequency. Now I would like to attach that antenna to the tree (wood). But, due to Why does placing an antenna far from the wood increase the efficiency of ...
Sai's user avatar
  • 27
1 vote
1 answer
179 views

Why does placing an antenna far from the wood increase the efficiency of the antenna?

I designed a monopole antenna at 868MHz frequency. I placed wood as the surrounding material. I noticed that placing the antenna far from the wood increases the efficiency of the antenna. Can anyone ...
Sai's user avatar
  • 27
0 votes
2 answers
253 views

Is it possible to create a device that can decode the EM waves generated from an electronic machine?

I recently watched a movie in which the hero (a robber) invents a device that can capture and decode the EM waves generated from an Automated Teller Machine (ATM) during its use. The movie claims that ...
Sasikuttan's user avatar
0 votes
4 answers
217 views

FCC testing for boards with programmable firmware

I'm curious how FCC conformity testing is done on PCBs that contain devices with programmable firmware. Specifically, boards that are designed to allow the end-user to reprogram the firmware (such as ...
Sittin Hawk's user avatar
1 vote
2 answers
482 views

What are up-screened components?

What are up-screened components/devices in the frame of qualification of electronic components? How is it done?
lordlothard's user avatar
0 votes
2 answers
81 views

Calculating loss due to emission of EM waves (AC)

In AC due to the fact that electrons are accelerated back and forth they emit electromagnetic radiation. Electromagnetic radiation must depend on the value of AC because more accelerated charges emit ...
Cartoon Ryan's user avatar
0 votes
1 answer
1k views

Finding the side lobe level of an antenna array

I have a circular antenna array with N elements, for which the array factor can be defined as follows: $$AF(\phi)=\sum_{n=1}^N I_n \cdot e^{j \cdot(kr \cdot \cos(\phi-phi_n)+\beta_n}$$ I search a lot, ...
Reza_va's user avatar
0 votes
1 answer
51 views

Derivation of Dolph-Taylor Synthesis

Today, I was trying to deduce by myself the Dolph-Taylor Synthesis. After arriving at the expression: $$AF(\theta) = P_{N-1} \left( \cos \left( \frac{\psi}{2} \right) \right) = T_{N-1} \left(x_o \cos \...
user3141592's user avatar
0 votes
0 answers
138 views

How to determine radiation at a certain distance from a sunlamp

I have a sunlamp, with four UV bulbs, emitting UVA and UVB. These are parallel-mounted tube bulbs and the total area of the light emitting area is 20 cm × 25 cm = 0.05 m2. Each bulb is 15 W and so ...
Mark Roworth's user avatar
0 votes
1 answer
97 views

Removing collected charges in a IC CMOS circuit exposed under a 30keV electron beam source

I would like to know if there is any mechanism (for example UV light exposition) to remove charges collected in an IC CMOS circuit that was exposed under a 30keV electron beam source. Presumably, ...
Jorge Johanny Sáenz Noval's user avatar
-2 votes
1 answer
241 views

400Mhz frequence HackRF One

All, Sorry but I am new to this topic and have no experience with SDR myself.First, I briefly give the hardware that I am using: HackRF One Following antenna: https://zsecurity.org/product/atheros-...
HereToLearn's user avatar
0 votes
1 answer
432 views

How can someone determine from the surface current distribution the electric field polarization?

How someone can determine by looking at the surface current direction what e-field components to expect? For example only \$E_\theta\$ or only \$E_\phi\$ ?
bigboss's user avatar
  • 15
0 votes
1 answer
144 views

With Bluetooth turned off in PC settings, do keyboards and mice still emit radiation? [closed]

Do you know if a wireless mouse emits radiation in wired mode? Using the USB cable, With Bluetooth turned off, but with the switch set to "On"? And also do you know if a wireless keyboard, ...
Jack's user avatar
  • 3
0 votes
0 answers
153 views

Where are the sensors of the EMF/RF meter on the circuit board?

In the attached photo you can see the PCB of a simple EMF/RF meter. This meter shows, at the same time, the values of the electric field, magnetic field, and power density (see small illustration on ...
Gary's user avatar
  • 13
1 vote
1 answer
70 views

What is relation between power deposition and frequency?

1. What is relation between power deposition and frequency in electromagnetic waves? 2. Is it true that even very low power elec.mag.waves can be "dangerous" for long time health if ...
Anonymous's user avatar
  • 111
0 votes
0 answers
50 views

Maximum Allowed Radiated Continous Wave Power in 61.25GHz ISM Band

I am looking into a possibility for 60GHz energy harvesting for low power sensor nodes and I am little confused about the differences I have found between the US and European regulations related to ...
Horror Vacui's user avatar
  • 1,397
0 votes
2 answers
3k views

How 3mG can be dangerous if the Earth's magnetic field is 500mG? [closed]

All the things I have read says that magnetic fields above 3milligauss is dangerous for people. How this can be true if the Earth has a magnetic field of 500mG? Do smartphones and gaussmeters measure ...
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