This one single video is more informative than hundreds of articles about radiowaves I've ever read! I had no idea that radio waves had polarity! Thanx a lot!
Excellent , the best explanation I have ever seen . I'm an ignoramus when it come to how radio works . And you have helped me a lot to understand how it works . Thank you for posting !
Fantastic vid. I was trained in Strategic Microwave Communications Systems Repair (26V20) years ago in the Army. Late 70s. They never had a vid as clear as this. Sure would have helped. Now I teach Middle School Science, and when we get to the sections on Energy, Electricity and Magnetism, I use vids like these to get the principles across to the kids. Thank you for taking the time to create and share this vid.
This video is really great. I am astrophysicist (working in optical and infra-red astronomy) who will go observe soon with a large radio telescope, thus I needed to learn as much as possible about radio stuff (telescopes, antenna, polarization, receivers,...). This video really helps. Thanks!!
What happens to the electrical signal as it reaches the radio wave? Does it generates a high frequency electrical signals and low voltage or maybe I'm mistaken?
This is also one of the best videos about radio in general and broadcast in particular that I have seen. I already took a few screen shots of it for a presentation that I made about radio relay systems for a sales colleague. I am RF system specialist, engineer and long time licensed ham as OZ7ACS too. I am trying to teach electronics and RF to my son and then I stumbled upon this excellent video. Keep up the good work and please make more videos like this one about more subjects within RF and antennas!
Outstanding video. I plan to require my employees (who are not trained technicians) to view this to give them a few more things to think about. I've had a ham license for 53 years and have been in the two-way and broadcast services industry for 42 years. I've been in business 31 years and I didn't know about the "solar winds" night time effect on the Ionosphere. There's always some thing new to learn before we ending up leaving this rock.
water blocks radio signal is not true. actually water carries rf further. when ever i go beside a river or lake or sea i get stronger signal than other places. i think they need a more to discover
I searched through numerous videos looking to understand radio waves and antenna length and by far this is the best video I found. Thank you so much for making this video!!
For explanatory purposes, I like the optical engineer's view of RF; photons coming off the antenna in response to the varying AC driving voltage. As the driving voltage builds, it excites the conduction electrons into a higher orbit, and when it drops the electrons return to a more stable orbit, releasing their energy in the form of a photon at the frequency of the driving voltage. The photons, traveling from the antenna, are picked up by the receiving antenna and induce a voltage in the antenna elements.
11:02 is what makes world wide radio contacts a regular thing for Amateurs and Broadcast stations. It's a bit more complicated than presented here and many more factors play into it. The lower frequencies are more predictable and the higher ones can be "magic" hence the "Magic Band" of 6 meters (50-54mHz in USA). Enhanced propagation is what makes things exciting on the amateur bands.
I already have some knowledge of antennas but I must say that this is a very good video on the subject. The different aspects of antennas and radios were discussed in a very clear way.
Dishes are used for very high frequencies, in the Gigahertz. The parabolic shape of the dish focuses the high frequencies into a very tight beam, this allows almost all the energy to be directed in one direction. When receiving the dish again focuses the received signal and amplifies it. Dishes work with both horizontal, vertical and circular polarized RF.
I have looked all over the place for some explanation about radio polarization. Especially what circular polarization is. Never would've thought i'd find the answer in a youtube video. Very detailed information in your video, thank you very much.
Brilliant! This is the best informational video I have ever watched on you tube! Very easy to understand!!! Radio waves have been difficult for me to grasp but this video helped me under stand soooooo much! Thank you sooooooo much!
I believe the crossed polarity as you've described is "dual polarity". Circular polarity is when the horizontal and vertical signals are out of phase and create a rotation in the polarity. A spin stabilized satellite most clearly demonstrates how circular polarization works. This WIKI has an excellent graphic and explanation: en.wikipedia.org/wiki/Circular_polarization
Excellent video, narration and animationns! This is EXTEMELY helpful for me to send to my sons who I am getting into Ham / Amateur radio! Thanks so much and keep them comming! :)
As a young ham i used to love 'sporadic E' some summer nights to talk up to 100's km's on my 2 metre homebrew. The E layer in the ionoshere sometimes ionizes in a way that VHF signals would bounce off it thereby effectively lengthening the horizon, sometimes for seconds or minutes occasionally for hours lol. In the 1970's govt's published prediction tables for HF propagation over DX, as different bands fron 3 to 30mhz would bounce repeately at different times. This enabled os staff to warm up the next Tx ready for opening, to keep those RTTY's going. Music to my ears!
Not sure about anyone else. This was very helpful on understanding how to use my RC to pilot my drone much farther I didn't understand that I had to be pointing my flat panels at the craft.
The only fear I have is the ability for governments to watch us 24/7. They can do this with home routers already, there is no telling how good it is with millimeter wave technology. I don’t care if I’m not doing anything wrong. We all have a right to privacy.
Mostly its the size and shape of the antenna that affects how much of a frequency it absorbs or emits. A wire strung out will transmit and receive a number of frequencies but not very efficiently, nor with any directivity. Sizing and shaping an antenna allows it to resonate more easily with a smaller range of frequencies and its shape lets it direct the area or pattern it transmits to or receives from. For transmit antennas they get bigger as the power they transmit increases. Hope this helps
Thank you for the awesome video. Very interesting. If you have the time will you make a complimentary video explaining how the information is actually encoded into the wave?
Signal processing can get complicated fast. If you are interested in some of the math behind it, look at 3blue1brown's video on Fourier transform, explains the topic amazingly. I haven't seen a good video explaining signal encoding yet so I'm all ears for recomendations.
It’s called modulation and can require the understanding of circuit design but a very simple explanation is that bandwidth is directly proportional to the frequency of a carrier (or transmit frequency). The higher the frequency the more available bandwidth (BW). The information is “modulated” onto the carrier via a circuit called a “mixer”. The information can never exceed the BW or the carrier frequency. The trade off is that higher frequencies become much more directional and tend to experience higher propagation loss. Microwave signals need to have the antennas directly lined up for maximum transmission. This video does a good job of relating basic RF and mW antenna propagation. If you like math and are interested in this topic Engineering is a fascinating career path and is well worth the effort to get a degree in Electrical Engineering. All it takes is a desire to learn. I’ve been an Engineer for 30 years and still learn new things all the time. Not trying to preach but a degree will serve you very well over a lifetime.
The tallest antenna was the Warsaw antella at 2,120 feet, but it collapsed. Today, the tallest antenna is the Tokyo Skytree antenna at 2,080 feet. In Ontario, Canada, the CN Tower, standing at 1,815 feet, is an antenna that also serves as an observation tower for people. The smallest antenna is only 14 mm by 11 mm. This was a great video. They should have mentioned the layers of the atmosphere, identified by capital letters (D, E, F1 and F2, increasing in height in the ionosphere), which reflect radio waves, and are different between day and night. For example, only during the night does the D layer reflect back to Earth SW radio waves, such as 2 meters to 80 meters, used for continuous-wave communication (Morse Code) by radio (Ham) operators. Frank Reiser M.S. KB2VNG Frank Reiser Video/Audio Service Caldwell, NJ., U.S.A. (973) 226-3476
Awesome, very informative. I have got many answers to the questions that i used to think when i was a kid haha. Thanks for sharing and making this wonderful and informative visualization about Radio Waves.
Just as an additional note - EM waves may be harmful if the radiation intensity is large enough (so-called "thermal effects"), but the health effects when exposed to EM waves also depends on the characteristics of the waveform which is transmitted. A number of studies have been performed to research the effects of EM waves, particularly with center frequencies used in cellular and Wi-Fi, combined with the actual waveforms to determine whether the exposure has any effect on mammalian health. Some of these studies have shown that these particular center frequencies and waveforms are coupled to e.g. VGCC activation in cells - but don't take my word for it - go ahead and read the research papers!
Great video! I enjoyed it very much. One observation, and with all due respect: It sounded to me like you said nuke-ya-lur. According to Websters dictionary it is pronounced: noo-klee-er.
The diagram at 7:06 has several errors in it. 1) This is not the pattern of "an" directional antenna, it is the pattern of any Yagi antenna with a certain design and in a certain environment. 2) The blue part where you have no radio waves is also wrong. A directional antenna transmits and receives in ALL directions (just not equally well).
Great video Except: at 12:30 it sounds like All radio waves follow the inverse squared law (twice the distance=1/4th the signal strength). However, if it is a directional radiation source as you discussed earlier in video, there will be more than 1/4th the signal strength b/c it's not omnidirectional (a sphere shape is what gives rise to the inverse square law).
I have a couple of questions. The graphics in this video mostly show radio waves travelling in a straight line and the same size. (1) I thought all EM waves propagate through space as a spherical wavefront from the point of source (until are blocked or reflected), hence the inverse square law applied to the strength at a given distance from the source. (2) When a dish antenna is used to improve gain, is the strength of signal concentrated as a cylinder parallel to the antenna, as a cone (in which case how is the cone radius calculated for a given distance), or as a hemisphere? Be warned ... I'm a newbie!
Your proposition (1) is right, but only for point sources as you noted. (2) is more specific and I can't answer whether or not it is correct since I have not studied this type of antenna.
this was very good, but do not treat RF as something "like" light. lightwaves and radiowaves are one and the same thing. radiowaves do not travel "near" lightspeed, they travel at lightspeed as they ARE light. great video, keep up the good work.
I was wondering if there may be some exceptions to RF ionization because of my experience: In 1996, I was installing a 410C4 at the 200' level of a 300' deactivated AM tower when I received a serious RF burn that lasted more than ten months. The landlord was supposed turn the active tower down. He said to hammer the lightening balls together. I did not feel right about it but, was young and my older coworker hammered and guilted me into climbing. Felt prickling in my feet and hands as I climbed and thought it was plant stuff from the overgrown field. Realized that it wasn't plants but ignored it- stupid kid! Hoisted 7\8" heliax up. When I touched the cable hoisting braid a blue arc went through my glove and opened up the end of my left index finger, cauterized- luckily I play 6 string.. calluses. Within the next day I started experiencing itchiness.. it became unbearable and affected my whole body, symmetrically: arms would itch, then legs, head, groin, tmi ... This feeling was similar to putting cold, outside hands under warm water, magnified much more. Many doctors later, and many foolish ideas. A natural path did a Bio-Terrain Assessment on me. He could not understand the results other than saying that it appeared that my nerves were cooked, was acidic, my sitting/standing blood pressure was negligible and my body was releasing histamines that made me feel like I was allegic to... everything, I guess. Reactine was the only 'accepted' medicine that helped relieve the crazy itching. puffing helped. Electrical engineers said that I was "electrocuted"... right word,, ? Makes sense, that I completed the circuit and 30,000 Watts of Burton Cummings sailed through me. ('Stand Tall' was playing on the radio station that owned the site). One said that I would itch for awhile... try 10months! I did many radicle self treatments and tried spiritual de-cookoo-ing. It sent me to the dark night of the soul. Finally, ten months later it started fading to nothing.
RF-burns are not "Ionization"- they are just the heating effect of RF-current. AM towers are usually insulated from the ground so they are subject to collect considerable RF from nearby transmitters. Usually if you are not touching something grounded you don't feel it. But if you are hauling up wires or coax they can be at a different potential and you will. Note too that static electricity from wind or nearby storms can also accumulate on ungrounded towers. I was a transmitter engineer for many years and sometimes the transmitter would trip off for a second as an arc would jump the johnny-balls at the tower. I'd look out the door and see that a thunderstorm was coming.
Excellent video, however I am still confused on polarization. Are not radio waves polarized perpendicular to the antenna? Such as a vertical antenna emitting a horizontal wave?
It doesn't reduce the distance in half but it does reduce the signal strength in a given plane by half. Originally FM stations broadcast horizontal only but when FM car radios became popular many stations switch to circular polarization to be picked up better by the vertical antennas used on cars. But to maintain the same horizontal signal strength they had to double the transmitter output power or double the number of bays on the transmit antenna.
It's no coincidence that the dual wave function representing the propagation of RF is almost identical to that of light. Seems that in 1873, Maxwell published his Theases (Maxwells equation) on Electricity and Magnetism, which contained a full mathematical description of the behavior of electric and magnetic fields. Later, Heinrich Hertz confirmed Maxwell's theory experimentally by generating and detecting radio waves in the laboratory and demonstrating that these waves behaved exactly like visible light, exhibiting properties such as reflection, refraction, diffraction and interference. Their collaboration laid the groundwork for the development of radio communications, television and the like..
Hi ! Nice video!! I want to ask you... if I only care about the receiving signals (don’t care about transmitting) would I have to prefer a high dbi antenna or a medium?? Is higher dbi antenna more sensitive to receive??? Thank you in advance
If you're interested in radio, this is the best video I've found to start out.
@صادق حسن التميمي البصراوي aáataayaáyÁpyyaytyyayuay9yyayaaayytaayaytyy0yytólotáóoķoä7ttýatyayaaaaaaaáyaĺñkljjlmvmbmblb00ápa
This one single video is more informative than hundreds of articles about radiowaves I've ever read! I had no idea that radio waves had polarity! Thanx a lot!
a must watch video for everyone trying to get into RF. many basic topics clearly explained. thank you !!
Agreed
The best video about this issue I have saw. Congrats!
Agreed...a fine basic intro to terms and good simple graphics.
Absolutely the best qualitative antenna video out there. You hit all the main points.
Excellent , the best explanation I have ever seen . I'm an ignoramus when it come to how radio works . And you have helped me a lot to understand how it works . Thank you for posting !
Fantastic vid. I was trained in Strategic Microwave Communications Systems Repair (26V20) years ago in the Army. Late 70s. They never had a vid as clear as this. Sure would have helped. Now I teach Middle School Science, and when we get to the sections on Energy, Electricity and Magnetism, I use vids like these to get the principles across to the kids. Thank you for taking the time to create and share this vid.
How do one get a radio frequency overhead ?
This video is really great. I am astrophysicist (working in optical and infra-red astronomy) who will go observe soon with a large radio telescope, thus I needed to learn as much as possible about radio stuff (telescopes, antenna, polarization, receivers,...). This video really helps. Thanks!!
What happens to the electrical signal as it reaches the radio wave? Does it generates a high frequency electrical signals and low voltage or maybe I'm mistaken?
This is also one of the best videos about radio in general and broadcast in particular that I have seen. I already took a few screen shots of it for a presentation that I made about radio relay systems for a sales colleague. I am RF system specialist, engineer and long time licensed ham as OZ7ACS too. I am trying to teach electronics and RF to my son and then I stumbled upon this excellent video. Keep up the good work and please make more videos like this one about more subjects within RF and antennas!
I am glad you and your students found my video tutorial useful. Thanks for your kind words. Russ
The earth is flat. The idea that radio waves would need a curved earth to propagate makes no sense.
@@ToolFan68 bros smarter than a fan
im here after 12 years of u uploading thiss vid
Outstanding video. I plan to require my employees (who are not trained technicians) to view this to give them a few more things to think about. I've had a ham license for 53 years and have been in the two-way and broadcast services industry for 42 years. I've been in business 31 years and I didn't know about the "solar winds" night time effect on the Ionosphere. There's always some thing new to learn before we ending up leaving this rock.
water blocks radio signal is not true. actually water carries rf further. when ever i go beside a river or lake or sea i get stronger signal than other places. i think they need a more to discover
asif iqbaL paLash That's because the signal bounces off the water's surface. It cannot penetrate the water very much.
then why i my music volume on radio get stronger while i am beside a river...
i observed similar incident in many places.
FM - 11-666
I searched through numerous videos looking to understand radio waves and antenna length and by far this is the best video I found. Thank you so much for making this video!!
For explanatory purposes, I like the optical engineer's view of RF; photons coming off the antenna in response to the varying AC driving voltage. As the driving voltage builds, it excites the conduction electrons into a higher orbit, and when it drops the electrons return to a more stable orbit, releasing their energy in the form of a photon at the frequency of the driving voltage. The photons, traveling from the antenna, are picked up by the receiving antenna and induce a voltage in the antenna elements.
11:02 is what makes world wide radio contacts a regular thing for Amateurs and Broadcast stations. It's a bit more complicated than presented here and many more factors play into it. The lower frequencies are more predictable and the higher ones can be "magic" hence the "Magic Band" of 6 meters (50-54mHz in USA). Enhanced propagation is what makes things exciting on the amateur bands.
Outstanding! It’s unimaginable that the radio frequency waves travel at the same speed as the speed of light. Thanks for all this Good information.
I already have some knowledge of antennas but I must say that this is a very good video on the subject. The different aspects of antennas and radios were discussed in a very clear way.
Dishes are used for very high frequencies, in the Gigahertz. The parabolic shape of the dish focuses the high frequencies into a very tight beam, this allows almost all the energy to be directed in one direction. When receiving the dish again focuses the received signal and amplifies it. Dishes work with both horizontal, vertical and circular polarized RF.
This video was really helpful. Instead of reading about radio wave watching this video was much worth. I wish it could have been in much deeper way.
I have looked all over the place for some explanation about radio polarization. Especially what circular polarization is. Never would've thought i'd find the answer in a youtube video. Very detailed information in your video, thank you very much.
Brilliant video. Don't know why anyone would not like this.
This is best video on radio that I have ever seen. Excellent work!
This is very well done. Clear, paced well, good animations. I used it as part of my College for Kids class on amateur radio. Thanks.
Came for clear information, received clear information. Thanks for making me smarter today.
Brilliant! This is the best informational video I have ever watched on you tube! Very easy to understand!!! Radio waves have been difficult for me to grasp but this video helped me under stand soooooo much! Thank you sooooooo much!
This is an EXCELLENT educational video. My only suggestion two 7+ minutes long Parts 1 & 2. Thank you.
This is a very very helpful video, clarified most of the issues I haven't been able to understanding for years. Thank you so much.
I believe the crossed polarity as you've described is "dual polarity". Circular polarity is when the horizontal and vertical signals are out of phase and create a rotation in the polarity. A spin stabilized satellite most clearly demonstrates how circular polarization works. This WIKI has an excellent graphic and explanation: en.wikipedia.org/wiki/Circular_polarization
Simple, but powerfull, very didactic, better than many of our university teachers, best regards from Colombia OnLineEngineer
Excellent video, narration and animationns! This is EXTEMELY helpful for me to send to my sons who I am getting into Ham / Amateur radio! Thanks so much and keep them comming! :)
As a young ham i used to love 'sporadic E' some summer nights to talk up to 100's km's on my 2 metre homebrew. The E layer in the ionoshere sometimes ionizes in a way that VHF signals would bounce off it thereby effectively lengthening the horizon, sometimes for seconds or minutes occasionally for hours lol. In the 1970's govt's published prediction tables for HF propagation over DX, as different bands fron 3 to 30mhz would bounce repeately at different times. This enabled os staff to warm up the next Tx ready for opening, to keep those RTTY's going. Music to my ears!
Not sure about anyone else. This was very helpful on understanding how to use my RC to pilot my drone much farther I didn't understand that I had to be pointing my flat panels at the craft.
I know it's a lot to learn but this is the first step for people to understand how 5G works instead of being afraid of it.
The only fear I have is the ability for governments to watch us 24/7. They can do this with home routers already, there is no telling how good it is with millimeter wave technology. I don’t care if I’m not doing anything wrong. We all have a right to privacy.
@@zach240don’t worry. Your tinfoil hat will protect you.
5g isn’t radio waves though it’s microwaves
simple and sharpen explanations ... Very good
73
Mostly its the size and shape of the antenna that affects how much of a frequency it absorbs or emits. A wire strung out will transmit and receive a number of frequencies but not very efficiently, nor with any directivity. Sizing and shaping an antenna allows it to resonate more easily with a smaller range of frequencies and its shape lets it direct the area or pattern it transmits to or receives from. For transmit antennas they get bigger as the power they transmit increases. Hope this helps
An excellent video with many good animations. I imagine you took quite a long time and a lot of effort to add so many animations to your slides.
wow, thank you. literally everything I wanted to know regarding this subject was answered in this video.
Thank you for this very lively and informative video, I now understand RF a lot better than I did before watching. Good job!
a brief but lucid tutorial. thank you for posting it.
well explained sir. now i am doing a project on designing an antenna. your video helped me alot.
Thank you for the awesome video. Very interesting. If you have the time will you make a complimentary video explaining how the information is actually encoded into the wave?
Signal processing can get complicated fast. If you are interested in some of the math behind it, look at 3blue1brown's video on Fourier transform, explains the topic amazingly. I haven't seen a good video explaining signal encoding yet so I'm all ears for recomendations.
It’s called modulation and can require the understanding of circuit design but a very simple explanation is that bandwidth is directly proportional to the frequency of a carrier (or transmit frequency). The higher the frequency the more available bandwidth (BW). The information is “modulated” onto the carrier via a circuit called a “mixer”. The information can never exceed the BW or the carrier frequency. The trade off is that higher frequencies become much more directional and tend to experience higher propagation loss. Microwave signals need to have the antennas directly lined up for maximum transmission. This video does a good job of relating basic RF and mW antenna propagation. If you like math and are interested in this topic Engineering is a fascinating career path and is well worth the effort to get a degree in Electrical Engineering. All it takes is a desire to learn. I’ve been an Engineer for 30 years and still learn new things all the time. Not trying to preach but a degree will serve you very well over a lifetime.
A degree is fundamentally useless. Use the internet.
Outstanding Video. Concepts explained in simple way.
I´ve been thinking about this video for a while now. Thanks!
Excellent video. Best one I've seen so far. Many thanks!
Where was this in 1992, when I really needed it. Books and more books.
so simple, yet so helpful ... thnx!
wow!I been missing this..this excellent
The tallest antenna was the Warsaw antella at 2,120 feet, but it collapsed. Today, the tallest antenna is the Tokyo Skytree antenna at 2,080 feet. In Ontario, Canada, the CN Tower, standing at 1,815 feet, is an antenna that also serves as an observation tower for people. The smallest antenna is only 14 mm by 11 mm. This was a great video. They should have mentioned the layers of the atmosphere, identified by capital letters (D, E, F1 and F2, increasing in height in the ionosphere), which reflect radio waves, and are different between day and night. For example, only during the night does the D layer reflect back to Earth SW radio waves, such as 2 meters to 80 meters, used for continuous-wave communication (Morse Code) by radio (Ham) operators.
Frank Reiser M.S. KB2VNG
Frank Reiser Video/Audio Service
Caldwell, NJ., U.S.A.
(973) 226-3476
Excellent, Excellent, Excellent!!!! Well done video
Absolutely the best video on this subject!
Awesome, very informative. I have got many answers to the questions that i used to think when i was a kid haha. Thanks for sharing and making this wonderful and informative visualization about Radio Waves.
Thank you very much for publishing this video. Great Help
Awesome video! Thanks heaps for putting the time in to make it. You've helped me understand the way radio waves behave a lot better. :-)
Thanks for your hard work
Best vedio on TH-cam
Very well explained! A really great video, with very useful information. Congrats!
Excellent ! thank you for sharing this
Very useful information and done in a very understandable way. Thank you.
Just as an additional note - EM waves may be harmful if the radiation intensity is large enough (so-called "thermal effects"), but the health effects when exposed to EM waves also depends on the characteristics of the waveform which is transmitted. A number of studies have been performed to research the effects of EM waves, particularly with center frequencies used in cellular and Wi-Fi, combined with the actual waveforms to determine whether the exposure has any effect on mammalian health.
Some of these studies have shown that these particular center frequencies and waveforms are coupled to e.g. VGCC activation in cells - but don't take my word for it - go ahead and read the research papers!
On 10 W radios, for example, there is advice on the danger of seeing the waveguide directly or standing in front of it. Yes, radios are hazardous.
Great work. Clarified why I would like to have a circularly polarized yagi for satelllite work.
its so organized and useful, thanks so much for making this
The on line engineer I like your utube videos are awesome
Greetings from Sweden 🇸🇪
Awesome explanation!
You just got yourself a new subscriber 🤖
Well described and good video
Great video! I enjoyed it very much. One observation, and with all due respect: It sounded to me like you said nuke-ya-lur. According to Websters dictionary it is pronounced: noo-klee-er.
The diagram at 7:06 has several errors in it. 1) This is not the pattern of "an" directional antenna, it is the pattern of any Yagi antenna with a certain design and in a certain environment. 2) The blue part where you have no radio waves is also wrong. A directional antenna transmits and receives in ALL directions (just not equally well).
12:17 This is why broadcasts of "Single Female Lawyer" never made it to Omicron Persei 8.
Hahahaha
Great reference!
***** Nobody loves Zoidberg.
Lmaoo did not expect this one
amazing presentation. very well presented.
Very good video so I could get some knowledge on radio waves
Great job! Very clear easy to comprehend.
Easy to understand, and information shared at a good speed.
Outstanding vedio & interesting &l like it
Great video Except: at 12:30 it sounds like All radio waves follow the inverse squared law (twice the distance=1/4th the signal strength). However, if it is a directional radiation source as you discussed earlier in video, there will be more than 1/4th the signal strength b/c it's not omnidirectional (a sphere shape is what gives rise to the inverse square law).
Very nicely and detailed demonstrated.
Understood it easily with the great explanation
Thanks, this really helped on some school work I was doing recently! :)
it would have been great to include also, how rf is generated and emitted
Great video! Thank you… ( did you mean ‘particles’ not ‘particals’ ? Spelling? )
Great explanation. Much obliged.
Well done. Thanks for Austin, Texas. May Jesus Christ bless you.
Excellent presentation.
I am curious to know what I did not get right on the tech side of things. Glad you liked it anyway.
Great introductory video 👍👍
Just amazing, thank you!!!
I have a couple of questions. The graphics in this video mostly show radio waves travelling in a straight line and the same size.
(1) I thought all EM waves propagate through space as a spherical wavefront from the point of source (until are blocked or reflected), hence the inverse square law applied to the strength at a given distance from the source.
(2) When a dish antenna is used to improve gain, is the strength of signal concentrated as a cylinder parallel to the antenna, as a cone (in which case how is the cone radius calculated for a given distance), or as a hemisphere?
Be warned ... I'm a newbie!
Your proposition (1) is right, but only for point sources as you noted. (2) is more specific and I can't answer whether or not it is correct since I have not studied this type of antenna.
this was very good, but do not treat RF as something "like" light.
lightwaves and radiowaves are one and the same thing.
radiowaves do not travel "near" lightspeed, they travel at lightspeed as they ARE light.
great video, keep up the good work.
I learned a lot from this video.
excellent animation with explanation ! thank you sir. !
I was wondering if there may be some exceptions to RF ionization because of my experience:
In 1996, I was installing a 410C4 at the 200' level of a 300' deactivated AM tower when I received a serious RF burn that lasted more than ten months.
The landlord was supposed turn the active tower down. He said to hammer the lightening balls together.
I did not feel right about it but, was young and my older coworker hammered and guilted me into climbing.
Felt prickling in my feet and hands as I climbed and thought it was plant stuff from the overgrown field.
Realized that it wasn't plants but ignored it- stupid kid!
Hoisted 7\8" heliax up. When I touched the cable hoisting braid a blue arc went through my glove and opened up the end of my left index finger, cauterized- luckily I play 6 string.. calluses.
Within the next day I started experiencing itchiness.. it became unbearable and affected my whole body, symmetrically: arms would itch, then legs, head, groin, tmi ... This feeling was similar to putting cold, outside hands under warm water, magnified much more.
Many doctors later, and many foolish ideas. A natural path did a Bio-Terrain Assessment on me. He could not understand the results other than saying that it appeared that my nerves were cooked, was acidic, my sitting/standing blood pressure was negligible and my body was releasing histamines that made me feel like I was allegic to... everything, I guess.
Reactine was the only 'accepted' medicine that helped relieve the crazy itching. puffing helped.
Electrical engineers said that I was "electrocuted"... right word,, ? Makes sense, that I completed the circuit and 30,000 Watts of Burton Cummings sailed through me. ('Stand Tall' was playing on the radio station that owned the site). One said that I would itch for awhile... try 10months!
I did many radicle self treatments and tried spiritual de-cookoo-ing. It sent me to the dark night of the soul.
Finally, ten months later it started fading to nothing.
RF-burns are not "Ionization"- they are just the heating effect of RF-current. AM towers are usually insulated from the ground so they are subject to collect considerable RF from nearby transmitters. Usually if you are not touching something grounded you don't feel it. But if you are hauling up wires or coax they can be at a different potential and you will. Note too that static electricity from wind or nearby storms can also accumulate on ungrounded towers. I was a transmitter engineer for many years and sometimes the transmitter would trip off for a second as an arc would jump the johnny-balls at the tower. I'd look out the door and see that a thunderstorm was coming.
So you became ionised?😥
best ever......... thanx a lot sir,
Excellent video, however I am still confused on polarization. Are not radio waves polarized perpendicular to the antenna? Such as a vertical antenna emitting a horizontal wave?
a vertical whip or dipole will give a vertically polarised signal. A horizontal dipole, loop or yagi will give a horizontally polarised one
Excellent production! 73 de AC6GM!
Great simple to understand video.
What an awesome video! Thanks.
Very clear and good video; thank you!
awesome video.!. thank u so much for uploading :)
the intro alone is worth a thumbs up :D
This explained all the questions i had except one. So if i use circular polarization, vs linear, does that reduce the distance by half?
It doesn't reduce the distance in half but it does reduce the signal strength in a given plane by half. Originally FM stations broadcast horizontal only but when FM car radios became popular many stations switch to circular polarization to be picked up better by the vertical antennas used on cars. But to maintain the same horizontal signal strength they had to double the transmitter output power or double the number of bays on the transmit antenna.
It's no coincidence that the dual wave function representing the propagation of RF is almost identical to that of light. Seems that in 1873, Maxwell published his Theases (Maxwells equation) on Electricity and Magnetism, which contained a full mathematical description of the behavior of electric and magnetic fields. Later, Heinrich Hertz confirmed Maxwell's theory experimentally by generating and detecting radio waves in the laboratory and demonstrating that these waves behaved exactly like visible light, exhibiting properties such as reflection, refraction, diffraction and interference. Their collaboration laid the groundwork for the development of radio communications, television and the like..
Very useful comprehensive video, Thanks.
Hi ! Nice video!! I want to ask you... if I only care about the receiving signals (don’t care about transmitting) would I have to prefer a high dbi antenna or a medium?? Is higher dbi antenna more sensitive to receive??? Thank you in advance
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