Antennas Part II: Radiation Demo & Antenna Modeling - DC To Daylight
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- čas přidán 30. 07. 2024
- Continuing our deep dive into antennas on DC to Daylight, Derek shows how a dipole antenna radiates RF and demonstrates how that RF behaves with a receive antenna. He also continues the conversation with RF expert Sterling Mann, and does some antenna modeling with a program called MMANA-GA.
In the next application-based episode, we'll build our own antenna, and use it to communicate around the globe!
Discuss the episode and ask Derek questions on the element14 Community! bit.ly/3J5eDO8
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#0:00 Welcome to DC To Daylight
#0:44 Demo
#2:26 Modeling
#8:20 Sterling Mann
#16:03 Give Your Feedback
#antenna #radiofrequency #maxwellequations #dipole #antennas - Věda a technologie
Im an expert at building antennas by mistake when designing PCBs 😂😂
😂
I was once mentored to treat every single trace on a pcb as a transmission line. Because ultimately it is; for very slow signals its just low frequency and thus very short and so you can get away with more (maybe, the rising edge of your signal is actually the driver of design). The faster the frequency/ data rate (in digital systems) the more you need to pay attention to things, even modeling the EM properties.
Inverse square law is a 1/x^2 decay rather than exponential as said in the video. Good video though
Lol, that bugs me too. It's such a common error in science videos. Just because there's an exponent involved does not make it exponential.
And the interesting part is that there happens to be an exponential term in the RaDAR and LiDAR equations in addition to the inverse square fall off. It is the term that accounts for absorption or extinction. But is definitely not the same as exponential fall off. And ironically, despite it being exponential it is a much more subtle effect than the inverse square law except in mediums like water.
Superb content and I love the phrase *"...DC to daylight..."* ❤
Hi Derek. I just found your videos and am excited to see the rest of them. I'm a new ham and am interested in learning more about antennas, so your videos are perfect. I'm eager to see the next video to learn how you build them. Thanks!
A 12oz aluminum pop can makes an excellent UHF mobile antenna. It's not durable. It does not like car washes. But, as a simple unity dipole on the roof of a car or truck, it performs extremely well. And it doubles as a 700/800Mhz antenna too.
I’ve always built antennas - but the nanoVNAs have made it so much cheaper and easier now. A real game changer- now I’m off into all types of filters as well.
Where can one learn about those and this?
NanoVNAs have totally switched things up for RF. They've made complex impedance measurements accessible to anyone for around fifty bucks. Amazing times we live in.. A VNA from the 80's or 90's would make a great boat anchor and be about the cost of a small boat!
@Deez Nutz check CZcams for W2AEW he did some great tutorials on nanoVNA and reading Smith charts.
@@DeezNutz-ce5se
czcams.com/video/xa6dqx9udcg/video.html
Excellent video Derek! That was a great deep dive!
Jiiiiiiim. Thanks man. Tell Chuck there's an FT-991a in the next video. I know he's a Yaesu fanboy like me!
This is amazing content! Sterling is a great guest too
Really superb content. Enjoyed the discussion . Brings back my memories of university days.
Thanks asif! -Derek
That was superb... much moooore of that please! :)
I came across this in my suggested by youtube it is good but your discussions are too dense for someone that is new. Like feed point? Was that where you connect your wires to the antenna? I am keen to learn how to make an antenna and attach a custom length wire to improve my mobile data signal as the 4g modem router doesn't have direct line of sight in the house and would love to add an antenna outside on the fence and run a wire inside through the fly screen to the modem router.
Could you put together a video on the new Orange Pi-5 running some GPIO examples? Do you have the O-Pi-5 26-pin breakout cable-board for a bread-board? 😎 Thank you.
I often informally teach tech, and that light-up antenna showing field strength is awesome. Where can I find out about building it?
Awesome..
What frequency were you using for your lightbulb dipole demo? Also, what is the minimum power wattage required to make this demo work? I'm interested in constructing something similar to this.
My main question is will this help me build a herf gun wave guide allowing for electronics to be disabled from a distance? 🤔
i'm interested to know how SDRs deal with digitally tuning without changing antenna length. Are they just more sensitive at some frequencies? or do they digitally change their length?
As per my knowledge, these types of RF transceiver uses a single wideband antenna for the rated frequency range and has a spectrum of values of S21 parameter for different frequencies and typically these S21 value is poor as compared to their single frequency counter tuned antenna
What happens if I send a different frequency signal to the dipole which was calculated to a different wavelength ? Does it radiate at all, even inefficiently ?
Providing you use a tuner to match impedance your transmitter will be happy but your efficiency may suffer.
If the antenna length is a multiple of the wavelength it will still work.
@@tedmead465 Thanks.
How can I make 74HC194 4-bit bidirectional universal shift ragister
Please help us
I would love to do some videos on 74xxx series logic, but it sounds like since there are 3 requests in the comments for this specific application, it is somewhat urgent? I would recommend joining the element14 community and asking questions there - there are many many folks that could help out with a faster turnaround time. However, I did have a look at the datasheet for the '194 4-bit bidirectional shift register, and the connections, timing diagrams, and conditions are highly detailed and is probably the best place to start. Of course, if you are overwhelmed and have trouble getting it to run the first time, e14 community is the place to be! -Derek
Whooooaaaa
You text on the screen said that the dipole formula accounts for RF traveling slower in the atmosphere. I think it should have said it accounts for RF traveling slower in wire or other metal.
I just want to hear the explanation 🎉 is it both the atmosphere and wire?
@@felixer80 it travels slower in wire than free space.
I have confidence in speculating that even in the atmosphere and Metal Conductor that there is an element of which a certain percentage of RF (E and B field) strength can act upon the Nucleus of each atom that it excites its respective electron to a state higher than its ground state, and if so, it would make sense that under a certain threshold of voltage (Likely on the level of milivolts or picovolts) there will be NO displacent of a certain amount of current that does not decelerate; hence remaining at the speed of light. This would, if true, imply that the threshold is different for each element (oxygen atoms for atmosphere or Copper per se) or its diatomic naturally occuring state (O2) as well as Compounds (CO2, H20, etc.) and Alloys (like Steel conductors).
This is just speculation because I have not come across any provable studies demonstrating this since it likely falls outside of basic electricity and more into the field of Nuclear Physics which understandably is has a lot of data still classified.
My thoughts are based on what we know about lightning being 6-7 times hotter than the surface of the sun and how you can see the blueish radiation around lightning bolts that is "temporary 03" (ozone) Synthesis. It seems plausible that all nuclei of atoms can be deformed in the presence of both E and B fields and that said deformation can modulate the ratio of both Extensive properties and Intensive properties; and it's the Intensive property of a Nucleus wherein the "weak force" that holds the neutron and protons together can be temporarily weakened long enough to alter the shape of electron orbitals that intrigues me. After all, even Endothermic chemical reactions have enough heat energy associated for Acids and Bases to exchange their respective Electrons and Protons when trying to achieve stability. The amount of time it takes to modulate the strength of these bonds is "Specific Impulse". Which acts in stages like quantum mechanics does.
Just imagine that a bolt of lightning isn't just a very powerful discharge of Electrical Potential but it's also capable of thermonuclear Fission.
2:00 it doesn’t decrease exponentially. It decreases by a power of -2
I went online for a wavelength calculator, and 432.1MHz has a wavelength of 27.3 inches, where did I go wrong ?
The elements in a dipole are typically 1/2 wavelengths. If it was a full wavelength would cancel out etc. least that’s what I understand
Dang, you’re in my neighborhood.
I also used to live in that area for a very long time - really grabbed my attention when Derek said where he was located. Wow.
Somthing died on your face😂
I ordered from these guys 219 days ago and dont have my order yet
Hey there, element14 Community and element14 presents are distinctly disconnected from the online stores, including element14 in the asia pacific/oceanic region. If you have problems with your order please take it up directly with them, you can use this link for your local store: bit.ly/40gefTI - sorry to hear you're having problems, but 219 days is a surprisingly long time to not chase it up! Good luck!
First
Like this comment if you think he looks like Robert Downey Jr.
Real life Tony Stark 😂
@element14presents >>> 👍👍