Antennas Part II: Radiation Demo & Antenna Modeling - DC To Daylight

[@kingsman428]

Superb content and I love the phrase *"...DC to daylight..."* ❤

[@digus]

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.

[@DeezNutz-ce5se]

Where can one learn about those and this?

[@digus]

@@DeezNutz-ce5se kzbin.info/www/bejne/rpKZlaSubtqXmck

[@nqobilesibisi3544]

Im an expert at building antennas by mistake when designing PCBs 😂😂

[@raduandreinegrila215]

😂

[@jflu1]

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.

[@gaillipfert9606]

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!

[@asif530]

Really superb content. Enjoyed the discussion . Brings back my memories of university days.

[@coledelong427]

Inverse square law is a 1/x^2 decay rather than exponential as said in the video. Good video though

[@whatelseison8970]

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.

[@lidarman2]

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.

[@charvakkarpe]

Glad someone else beat me to this comment. Some keen viewers out there.

[@paparapiropip87]

Was looking for this comment!

[@FEPLabsRadio]

Excellent video Derek! That was a great deep dive!

[@blenkiron1795]

This is amazing content! Sterling is a great guest too

[@joegeoghegan9493]

Is there documentation on how you made the simple little antenna and even the led connected the light up RF detector? I think what you demonstrated is a fantastic teaching tool

[@pesekmar]

That was superb... much moooore of that please! :)

[@billgeorge7607]

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.

[@Kevin89866]

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.

[@mewintle]

I often informally teach tech, and that light-up antenna showing field strength is awesome. Where can I find out about building it?

[@owenpenning1597]

2:00 it doesn’t decrease exponentially. It decreases by a power of -2

[@mdab121]

Ok that’s exactly what I wanted to comment :P

[@sagunmishra8212]

How can I make 74HC194 4-bit bidirectional universal shift ragister Please help us

[@qzorn4440]

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.

[@alanjewell9550]

I've always wondered about ferrite rod am antennas. As I understand them, they pick up primarily the magnetic component which induces a current in the coil wrapped around it. Does it pick up the electric field component at all? Also, they don't seem to be usable as transmit antennas, is that correct? All the am transmit antennas I've seen are a vertical mast or an array of suspended long wires.

[@SpeedDeamon95]

My main question is will this help me build a herf gun wave guide allowing for electronics to be disabled from a distance? 🤔

[@lloydbaker7337]

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.

[@kellyhofer]

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?

[@gopalagarwal9240]

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

[@oakspines7171]

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 ?

[@tedmead465]

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.

[@oakspines7171]

@@tedmead465 Thanks.

[@brucetouzel6484]

I went online for a wavelength calculator, and 432.1MHz has a wavelength of 27.3 inches, where did I go wrong ?

[@Len02013]

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

[@norbertdapunt1444]

Awesome..

[@rmccombs66]

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.

[@felixer80]

I just want to hear the explanation 🎉 is it both the atmosphere and wire?

[@rmccombs66]

@@felixer80 it travels slower in wire than free space.

[@joelmanthis9523]

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.

[@Hacker-at-Large]

Dang, you’re in my neighborhood.

[@arnotek]

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.

[@HeathHunnicutt]

1/r^2 decay is "inverse geometric" decay, not "inverse exponential" decay. Put another way, r^2 exhibits geometric growth, not exponential growth. An example of exponential growth of a function might be the factorial function, n! . This function grows roughly in proportion to e^n, which fits the definition of an exponential function -- one in which the independent variable appears in an exponent. It is not just a small discrepancy to call something exponential when it is not. Consider the example in the video, of doubling r. Doing so reduces the intensity by a factor of 4. Compare with factorial: 4! / 2! = 12, 6! / 3! = 120, while 8! / 4! = 1680. Not only do exponential functions grow faster than geometric functions, the rate of growth increases as it grows! This is why they are considered entirely different types of growth. Another angle on this: we have heard the P != NP is an interesting unproven conjecture of computer science. All algorithms which run in time proportional to a geometric function of their input size are in P, and no algorithms which run in time proportional to an exponential function of the input size ate in P. (They are in EXP.) It should make sense that the decline in radiative power per unit are declines geometrically. For an isotropic radiator, a conserved amount of energy spreads out over the increasing area of a sphere centered on the radiator. The area of this sphere is proportional to r^2. The received power is subject to geometric decay exactly because it is due to geometry that it decays. It is less exciting to say that the decay increases geometrically. After all 1/r is also a "geometric" decay, even though it is only linear. It may be helpful to enjoy the term "explosive" growth. Consider an actual explosion. The surface area of the shockwave for an isotropic explosion also increases as r^2. The volume of a fireball is proportional to r^3. Therefore, such functions can be said to grow "explosively," buy not "exponentially."

[@tristang8929]

I ordered from these guys 219 days ago and dont have my order yet

[@element14presents]

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[@mewintle]

Whooooaaaa

[@itzchi]

Like this comment if you think he looks like Robert Downey Jr. Real life Tony Stark 😂

[@supernova86]

A 7 minute isn't a deep dive. Terrible content

[@gad3]

Somthing died on your face😂

[@haval00]

First

[@Allan_aka_RocKITEman]

@element14presents >>> 👍👍