Long range detection system

Discussion in 'The Projects Forum' started by Kuhny1, Aug 29, 2016.

  1. Kuhny1

    Thread Starter New Member

    Jul 2, 2015
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    Hi all,

    So I've been looking for parts for a long range (miles) detection system for use in a weather radar, but I couldn't really find anything. I was thinking about using high power RF, but I don't think I want to tangle with the FCC 0.o

    Anyways, so after radar was blown out of the water, I figured about using LiDAR.

    I can make high powered lasers +2W. But it's just the case of detecting the reflection from a distance. Another problem would be using it during the day let alone using it for detection of around 5 miles.

    If anyone has any advice on how I can achieve long range detection, that would be really nice :)

    Budget of around $200

    Thanks!
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    A GPS connected to a walkie-talkie?
     
  3. Kuhny1

    Thread Starter New Member

    Jul 2, 2015
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    Um, what?

    I was planing to send something up into the atmosphere and receive echos from it. Can you please elaborate more on that suggestion?

    I know at this point that using lidar may be unreasonable.
     
  4. DickCappels

    Moderator

    Aug 21, 2008
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    This might be difficult to calibrate, but if you have thunderstorms in your area you might be able to capture electrical disturbance using directional antennas to get the direction and capture the crack of thunder using microphones and calculate the distance by the delay. You could even factor temperature and/or air pressure into the calculation.
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    For about $250 you can get a complete lightning detector and emulator evaluation kit from AMS (http://ams.com/eng/Support/Demoboar.../Wireless-Sensor-Connectivity/AS3935-Demo-Kit). That is not a direct link. You need to click on the hot link in it.

    I have seen that kit available for about $217 from other dealers. You can also buy the critical chip (< $10) and make your own.

    Lightning correlates well with turbulence and/or high winds and is probably a bigger worry to most than rain itself. Although, heavy rain, turbulence, and lightning do come as a family.

    John
     
  6. wayneh

    Expert

    Sep 9, 2010
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    You haven't said what you are trying to detect. Birds? Airplanes? Clouds? Missile launches?
     
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  7. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    I thought the TS said weather radar. That is not good for airplanes or birds. It does OK with clouds.
     
  8. Kuhny1

    Thread Starter New Member

    Jul 2, 2015
    20
    3
    Yes i have messed around with the AS3935 before and have actually made lightning detector with it but its not directional.

    I intended on detecting a reflected signal of what ever i send up in the atmosphere. High precipitation amounts clouds will reflect radio waves, so for this, i need to figure out a way to send the radio waves (or light, invisible preferably like, IR) and receive them without breaking the law. If i can figure out a way to make a directional antenna and pick up on electrical disturbances than that would work too, but i just dont know where to start with that. Because i tried to use a TV dish for my antenna, but i get way to much inference (60Hz) and it doesnt seem directional at all. And im pretty sure that they only work for microwave RF.

    But yes, if i can make something that can detect electrical disturbances in a directional manner, than that would be perfect for mapping out storms. Which is my main goal. Once i get the directional antenna right, I will hook it up to a beefy stepper and rotate it to sniff out RF fields.

    Now, would it be possible to remove the feed horns and make a lower frequency receiver/antenna feed for the dish antenna?

    Thanks!
     
  9. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Have you considered two detectors with the reception antennas at right angles? Then direction = arctan (intensity #1/intensity #2). It is unclear to me whether there is a 180° ambiguity with that ( as there is with ADF). But if there is, that should be as easily solved as the ambiguity with ADF is solved. ADF = automatic direction finder (used in aircraft mainly)

    BTW, did you get the emulator too?

    There is a ton of information on the Internet about using lighting detectors in the LF/VLF band for detection and ranging.

    John
     
  10. Kuhny1

    Thread Starter New Member

    Jul 2, 2015
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    3

    No i didnt get the emulator, just this:

    http://www.playingwithfusion.com/productview.php?pdid=22

    Well they do use a ferrite rod as an antenna, so there may be some "directionality" (is this a word? lol) with it. If it is directional, i havnt noticed it though. It seems to pick up strikes regardless where the ends of the rod are pointing. Maybe if i would get another one, mount it 90 degrees of the other and compare the raw pulse strength of the 2. That would give me its position, but only in this way (in the picture). Now if i can make my own directional antenna, that would be just as fine. Its always more fun to make things than buy it :D




    This seems to be turning more into thread with dealing RF now, so if it needs to be moved thats fine.
     
  11. BR-549

    Well-Known Member

    Sep 22, 2013
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    A "weather radar" does not detect lightning. It detects precipitation. The allowable frequency spectrum will be limited.

    It will need to be an active system. You might find experimental frequencies and appropriate power levels up there.

    But 200 bucks ain't gonna do it.
     
  12. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    GPS:Global Positioning System: An inexpensive receiver outputting digital data for position and altitude.

    Walkie-Talkie: An inexpensive radio transmitter and receiver combination capable of communicating with a similar unit.

    Put them together (you might want to parse the direct GPS data stream with a micro) and you have a signal telling you where the transmitter is. Put that transmitter in your device and call it a day.

    DO check how high/fast your mystery vehicle can travel: exceed certain limits and your device falls into a classification called a "munition."
     
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