Search results

  1. T

    Radiofrequency communication through tissue

    2.550 GHz is easy to work with and works well trough skin. I'd suggest looking around on NCBI as well.
  2. T

    How Do Microwave transmitters work without physical connections?

    So I recently picked up 40 of 10.525 GHz Microwave RADAR transmitters: I opened up one out of curiosity and had something like this (image attached) . I noticed some parts of the PCB aren't even connected to anything. How do the different shapes and sizes of the PCB interact with each-other...
  3. T

    Why does the sun affect radio wave propagation?

    I noticed HF radio waves travel farther and easier when the sun is out rather then during the night. Why?
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    Power Line powered FM radio

    I had an idea of building an FM receiver that is powered from the electromagnetic fields generated by power-lines. My question is , how can I make the electromagnetic field receiving antenna? Will a simple copper coil work? If so, can the same coil be used as the RF antenna or will that have to...
  5. T

    How do computers keep time without power?

    I know the CMOS battery keeps the time and BIOS settings , but what is powered by the batter to keep time? A crystal oscillator? And why is it so crucial to keep time on a regular desktop computer?
  6. T

    B Cell Phone Tower Cell Spacing

    Can't multiple different cell towers that close to each other cause interference? Thanks lol
  7. T

    B Cell Phone Tower Cell Spacing

    If Cellular network towers are supposedly divided in cells , like this image , then why do we loose connection even when outdoors and not inside or near any buildings/cars. Also why is it common to see more than 1 cell tower near each other?
  8. T

    Best Open source projects to contribute to?

    OpenCV is always an attention grabber, generally anything involving AI.
  9. T

    B Why does time only move forward and not backwards?

    Probably an unanswered question , just wondering what people have to say.
  10. T

    B Why does GPS require an accurate clock?

    Why do GPS need a cesium clock accurate to 10ns? Is this strictly for time keeping or is there some synchronization between satellites?
  11. T

    What makes a yagi antenna directional?

    How exactly do the elements "connect" to each other to make an antenna directional? I see some Yagi's have a reflector but most do not.
  12. T

    MATLAB Binary bitstream from QPSK with MATLAB?

    Hi , I am trying to extract the binary bitstream from QPSK using MATLAB. Will something like Frames = reshape(B,[],N) work? If not, can someone point me in another direction?
  13. T

    Tinspire calculator apps

    This website has some great Ti calc programs https://tiplanet.org/forum/portal.php
  14. T

    I How can I go about making a "Space Proof" coating?

    Yup , found this one http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.29.5395&rep=rep1&type=pdf
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    I How can I go about making a "Space Proof" coating?

    So I am planning on launching a Satellite to promote the Dogecoin cryptocurrency. One of the main points is printing/painting (Or whatever) the logo on the side of a metal panel. How can I make it so it doesn't melt off or turn white from radiation so quickly?
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    Electronics 3D Printed 2.25 Ghz Microwave RADAR horn antenna

    I lined the inside and outside of the horn with Microwave paint , seems to work well enough for my use,
  17. T

    In layman's terms , how strong is a 3 Tesla Magnet?

    I saw a post where someone was granted access to a 1.5 Tesla MRI. After some research I discovered a 3 Tesla MRI. How strong is this magnet?
  18. T

    Electronics 3D Printed 2.25 Ghz Microwave RADAR horn antenna

    I do not have a license but I am doing this in a controlled environment. I have not detected microwaves outside of the room I am testing in.,
  19. T

    Electronics 3D Printed 2.25 Ghz Microwave RADAR horn antenna

    Yeah I put the tape after to try to fix it. I will try brass with solder and thinner walls and let you know how it goes. Thanks.
  20. T

    Electronics 3D Printed 2.25 Ghz Microwave RADAR horn antenna

    There is no coax feedline as this is for an electronic transmitter using gunn diodes. I generated the horn measurements from a tool that used to be on this website : http://67.225.133.110/cgi-sys/defaultwebpage.cgi
  21. T

    Electronics 3D Printed 2.25 Ghz Microwave RADAR horn antenna

    This is S-Band, less than 1.5 W. The thick walls were meant to try to prevent microwave from leaking , which as you can see did not work.
  22. T

    Electronics 3D Printed 2.25 Ghz Microwave RADAR horn antenna

    So I printed this antenna with some conductive filament , however the microwaves seems to be going between the layers of the plastic. I surrounded it with Aluminum and still leaking, what can I do to fix it? Can conductive silver paint work?
  23. T

    B Why do rockets explode so easily when they tip over?

    I've seen the SpaceX fail videos, even when they tip over on water the rockets still explode. Why?
  24. T

    I What would be a useful application for 10 Thz nano-antennas?

    Reading: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3597338/ However I don't understand what a useful application for this is? can someone explain?
  25. T

    A ELI5 : Fourier Series

    Thank you! Finally something that made sense
  26. T

    A ELI5 : Fourier Series

    Basically what I understand is that it is a method to find different parts of a continuous signal.
  27. T

    A ELI5 : Fourier Series

    What are Fourier Series in layman's terms ?
  28. T

    A ELI5 : Fourier Series

    Working on some microwave stuff, read about this but can't understand the explanations online.
  29. T

    B Why do microcontrollers fail in a Vacuum?

    Well exactly what I mean, at -30inHg they just powered off and would not reboot
  30. T

    B Why do microcontrollers fail in a Vacuum?

    Arduino - https://www.arduino.cc/en/uploads/Main/arduino-uno-schematic.pdf rPi2 - https://www.raspberrypi.org/app/uploads/2012/04/Raspberry-Pi-Schematics-R1.0.pdf
  31. T

    B Why do microcontrollers fail in a Vacuum?

    I haven't tried measure that yet, but the power supply is not the issue
  32. T

    B Why do microcontrollers fail in a Vacuum?

    Yes, but those seem fine, were not bloated and no signs of leakage.
  33. T

    B Why do microcontrollers fail in a Vacuum?

    I was trying to log data inside a vacuum chamber, tried an arduino and a rasperry pi. When reaching -30inHg the devices just stopped working, they powered off, no data in or out and would not work ever again. Why? And no, they did not overheat.
  34. T

    Why do radio transmission harmonics occur?

    Thanks for the explanation, Just getting started with learning antenna theory.
  35. T

    Database for chemical and physical properties

    This sire might be more what you're looking for: http://www.chemspider.com/
  36. T

    Database for chemical and physical properties

    I use and love Pubchem which branches off NCBI if I remember correctly. https://pubchem.ncbi.nlm.nih.gov/ https://www.ncbi.nlm.nih.gov/
  37. T

    Why do radio transmission harmonics occur?

    What I understand about harmonics, is when something is transmitted at high power, the antenna resonates on other frequencies besides the desired one. But Why?
  38. T

    Pseudo Random Encryption?

    Interesting, Will try that, Do you know any good Encryption/Cipher analyzer software for Windows?
  39. T

    Pseudo Random Encryption?

    Hi, I am trying to decrypt something in a .txt file as a challenge from a friend, the file contains: pÿd“ÙÃÊÌßéh'rv‹"^÷ù O˜w؉D•ÍúúYíY’ ∞¶iÀªÆzI¥r=«Å∑F¸¡„;≥ûü¸ã7∂.ˆ– ã<¿µD~’ÅsG›îwA_4Gå#›¥’6ª˝_ÎaÍÑjù]ÚU3Y{äF-Ê#i 33(›öR `?™|¸ ®flîè+zÂ√œ/fiãìR˛˙˚∂ZëìƺΩÒ†»˘∂®∑‘¬z vóR◊r∂Øûp)E...
  40. T

    What are the best VPN solutions?

    No, some of them only accept pay-pal or credit card which links back to your name. Most VPN's like Norton keep logs.
  41. T

    What are the best VPN solutions?

    I use and love ExpressVPN, you can pay with bitcoin for almost 100% anonymous purchases, they keep no logs, have an internet kill switch.
  42. T

    B Why do chains on tires provide more traction in the snow?

    Wouldn't the chain easily get caught on a rock or something? And how does metal provide more traction than rubber wheels?
  43. T

    B How do digital radios tune?

    I get how analog ones with knobs tune by physically changing length of elements to match the frequency, but what about the ones that just have a screen and you type in what frequency you want?
  44. T

    Opening a car door at a high speed

    Yes, the door would theoretically be held open mechanically.
  45. T

    Is there a reaction for which the product is the catalyst?

    Is there a reaction of which the product is the catalyst for that same reaction?
  46. T

    Opening a car door at a high speed

    What would happen if a car is driving down a highway at 80Mph and one of the doors is fully opened. Will it make a big change and make it slow down or start turning?
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