#573c

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  • เผยแพร่เมื่อ 19 ม.ค. 2025

ความคิดเห็น • 53

  • @rossbrawley
    @rossbrawley 3 ปีที่แล้ว +6

    I've been a antenna building enthusiast since I was 15. I'm 37 now so it's I've done my share of experiments and trial and error.... I have never in 20 min gotten so much understanding of why some antenna work and others don't.... WOW! You are my favorite elmer now! Great job.

    • @IMSAIGuy
      @IMSAIGuy  3 ปีที่แล้ว +1

      Thank you

  • @clems6989
    @clems6989 ปีที่แล้ว +1

    love how excited you get over this subject. Lol good video !

  • @charlescartwright6367
    @charlescartwright6367 4 ปีที่แล้ว +10

    Aloha, the most entertaining explanation of transmission lines and antennas I have ever listened to. I am sure you have helped many of the younger generation of ham operators. Thanks for your time and efforts. Wouldn't it have been great to have the tiny-SA and the nano-VNA back in the 60's and 70's?

  • @SpiralDogma1990
    @SpiralDogma1990 หลายเดือนก่อน

    Best video ever. Watched probably over 100 videos about antennas and this one clicked instantly. Just started with 11m CB radio a few weeks ago. Thank you very much

  • @Steelplayer59
    @Steelplayer59 ปีที่แล้ว

    “Magic”. Yeah- you’re bringing the magic back to this hobby! Thanks for all the informative videos on the VNA and other test equipment we could only dream about years ago. I’m embarrassed to say I didn’t know that RF travels in the dielectric,despite being a ham for decades. Never too old to learn,I guess! I’ve built a few antennas,mainly by “recipes” and “seat of the pants”, so hoping that learning to use the NanoVNA will improve both my skills and antennas.

  • @ThermalWorld_
    @ThermalWorld_ 4 ปีที่แล้ว +2

    But what golden information for antenna technology.
    My Lora devices will now be more than happy with all this wonderful information for building antennas.
    Thank you man, you are gold for the knowledge of humanity.
    "If you can, maybe a few more episodes for the antennas would be nice.
    For many people, radio waves and antennas are still voodoo magic" 😅

  • @tomkeady1750
    @tomkeady1750 4 ปีที่แล้ว +2

    Thanks, this really pulled together some of the antenna information I've been trying to absorb (and retain) over the past few years. Finally able to begin to understand my NANOVNA as well. Really enjoy your enthusiasm. Nicely done.

  • @tomstrum6259
    @tomstrum6259 3 ปีที่แล้ว +1

    Thx for another informative demo..This explains why when building my CB ground plane antennas during my high school '60's,...the better looking & Intuitive "propper & correct" 90° angled ground plane radials produced discouraging High Vswr readings Despite length tuning attempts !!! ...Thx again for the cool video....?.tom

  • @bitemykrank1970
    @bitemykrank1970 3 ปีที่แล้ว

    I like your enthusiam, when you were describing the similarity between LED's and Antenna's it was like listening to a kid in a candy store...and VERY a informative video from start to finish to boot...I learned a lot more about things that I don't fully understand.

  • @arizona111
    @arizona111 3 ปีที่แล้ว +1

    Excellent vid! Pretty cool with your years of experience you are still so excited! Good stuff.

  • @sgifford1000
    @sgifford1000 11 หลายเดือนก่อน

    Those EM waves are alive! Thanks, got my first VNA!

  • @MarcusPocus
    @MarcusPocus 3 ปีที่แล้ว +1

    houww.. the electrons are happy now!! ..love the comic way you explain it!!!

  • @DavidLopez-bz4rj
    @DavidLopez-bz4rj 4 ปีที่แล้ว +1

    I love modelling antennas, building, and now testing and adjusting with the NanoVna.
    And of course, using them.

  • @davelapp4740
    @davelapp4740 4 ปีที่แล้ว +1

    I can honestly say I would never in a million years have expected to hear someone say solving Maxwell's equations was fun and sound like they actually mean it. I would have bet that they were being sarcastic. My hat's off to you!

    • @IMSAIGuy
      @IMSAIGuy  4 ปีที่แล้ว

      well, matlab does the heavy lifting

    • @davelapp4740
      @davelapp4740 4 ปีที่แล้ว

      @@IMSAIGuy I knew there had to be some secret :-)

  • @98xjdriver
    @98xjdriver 4 ปีที่แล้ว +2

    Nice explanation of a discone. Appreciate the diagrams also.

    • @IMSAIGuy
      @IMSAIGuy  4 ปีที่แล้ว +1

      I will be posting a video soon where I build a discone

  • @LionRoars918
    @LionRoars918 ปีที่แล้ว

    I just bought a Nanovna for exactly this reason. I am looking forward to testing my homebrew ADS-B 1/4 wave antenna very soon.

  • @PapasDino
    @PapasDino 4 ปีที่แล้ว +2

    I THINK the LPDA feed actually connects to all interconnected elements (usually at the smallest element) rather than the yagi feed point you showed for the log periodic. Nice to see your enthusiasm for the subject!

    • @IMSAIGuy
      @IMSAIGuy  4 ปีที่แล้ว +1

      yes I think that is right with phase reversal on each element

  • @needhelp2453
    @needhelp2453 3 ปีที่แล้ว +2

    Wow! Really interesting video. Thank you

  • @chriswalford4161
    @chriswalford4161 3 ปีที่แล้ว

    Really interesting. Thank you.
    I’m not a radio guy, but about 30 years ago I discover the cat’s cradle of the curtain arrays at BBC Rampisham, and was just fascinated by these huge towers precariously (apparently) holding up a filigree of radiators and reflectors and shapes and layer to transmit HF to directed targets thousands of miles away.
    The sound of the wind whistling through them…
    Then I discovered that the radiating pattern from these fixed arrays could be slewed up to 15* in 2 dimensions by playing with phase shift and I realising I was trying to understand magic.
    Then they reduced the magic to dust.
    In phases from 2017, they dropped the arrays and pulled over the huge steel towers with their sinister hammerheads and the silhouettes on the down were gone, leaving tell-tale concrete anchor blocks and tower foundations buried.

  • @combsrichard11
    @combsrichard11 4 ปีที่แล้ว +1

    Great explanations. I come from optics and love learning new insights for properties in the radio wave regime. Same effects but at a totally different scale. Lots to learn about these "big" radiators,😄👍

  • @johnwest7993
    @johnwest7993 3 ปีที่แล้ว

    The antenna array you mention may be the W5UN EME array in TX. It's not on tracks, but a computer-controlled vehicle chassis drives around in a circle to rotate it. Last I heard it had 64 long boom 2 meter horizontal and vertical Yagi beams.

    • @IMSAIGuy
      @IMSAIGuy  3 ปีที่แล้ว +1

      I think it was this:
      K5GW, the owner of Texas Towers, has a full-sized 3-element 80-meter yagi that uses Rohn 45 as the boom. The elements have mechanisms which vary the length of the elements so that the antenna performs well over the entire 500 kHz of the band.
      Years ago, there was an amateur radio operator who had a rhombic mounted on floats on his farm pond ("tank" here in Texas) that he rotated with 2-electric powered tractors mounted on tracks around the pond. That antenna gave gain on 160-meters through 10-meters with the exception of 15-meters. This antenna was featured in QST one month.
      Glen, K9STH

  • @janina3473
    @janina3473 3 ปีที่แล้ว

    Wooow, you are amazing i wish i had teachers like you

  • @rfmonkey4942
    @rfmonkey4942 3 ปีที่แล้ว

    nice , lots fun can be had with nano vna
    it really let people in the game who would not normally stand a chance
    i use them alot so compact !

  • @judd_s5643
    @judd_s5643 3 ปีที่แล้ว

    I’ve tuned damaged (slight) wave guides using a ball peen hammer and a TDR!

  • @technodruid
    @technodruid 2 ปีที่แล้ว

    You just gave me PTSD flashbacks to EM third year physics

  • @MrBanzoid
    @MrBanzoid 4 ปีที่แล้ว +2

    Thanks for your informative and enthusiastic video. You really know your stuff!
    Cheers
    Malc M0IYI

  • @TankmeUSA
    @TankmeUSA 3 ปีที่แล้ว

    Big fan of yours and a beginner antenna builder myself!!!
    I would love some explanation of the way some vertical antennas are feed , example Excalibur.64 or a maco v 5000 , that is what gets me a little confused

    • @IMSAIGuy
      @IMSAIGuy  3 ปีที่แล้ว +1

      I'll add it to the list

    • @TankmeUSA
      @TankmeUSA 3 ปีที่แล้ว

      @@IMSAIGuy thanks!!!
      here is a link to one of my first attempts without understanding the concept entirely.
      I would like to hear your critical opinion . th-cam.com/video/UJD8X40TKuQ/w-d-xo.html

    • @IMSAIGuy
      @IMSAIGuy  3 ปีที่แล้ว +1

      @@TankmeUSA looks like fun. I probably would have just put in four radials to the corners, but I'm lazy.

  • @ThinklikeTesla
    @ThinklikeTesla 4 ปีที่แล้ว

    IMSAI Guy, what references do you recommend for learning antenna physics, 3D Maxwell's equations, and so on? Currently making my way through Div, Grad, Curl, and All That: An Informal Text on Vector Calculus. (with the ARRL Antenna book waiting in the wings)

    • @IMSAIGuy
      @IMSAIGuy  4 ปีที่แล้ว

      Well I'm pretty old to be giving that advice. Got my degree in 1979. My textbook was: Electromagnetic fields and waves by Paul Lorrain and Dale Corson. It was the basics of E&M but did not touch on antennas much.

    • @IMSAIGuy
      @IMSAIGuy  4 ปีที่แล้ว

      eduguidehome.files.wordpress.com/2019/03/electromagnetic-fields-and-waves-by-paul-lorrain.pdf

  • @ahmedgaafar5369
    @ahmedgaafar5369 2 ปีที่แล้ว

    I really wish you were my professor during University.

    • @Bruce-f2r
      @Bruce-f2r 4 หลายเดือนก่อน

      Could you do a Video on a OP-Amp Log Amp with a feed back Diode and how to Caill uate the Output Voltage Thanks.

  • @warplanner8852
    @warplanner8852 3 ปีที่แล้ว

    "..don't ask me why.."
    Because you said a 1/2 wave dipole antenna's impedance is 73 ohms and your 1/4 vertical impedance was 23 ohms. If you had bent the radials down all the way, the antenna would resemble a half wave dipole and probably have an impedance close to the 73 ohms. I am sure the impedance is not linear from the 90 degree point to the "180 degree" point, but proportional.
    Try it. I did.

  • @seanmangan2769
    @seanmangan2769 4 ปีที่แล้ว +2

    What is an E and M wave?!? I know what an EM wave is...

  • @orhanboyac3693
    @orhanboyac3693 3 ปีที่แล้ว

    thankyou

  • @vidasvv
    @vidasvv 4 ปีที่แล้ว +1

    What a great explanation !
    73 N8AUM

  • @egbertgroot2737
    @egbertgroot2737 4 ปีที่แล้ว

    That was an easy impedance match! ;-)

  • @tahirsongelen7781
    @tahirsongelen7781 3 ปีที่แล้ว

    ALL YR TOPICS ARE EXCELENT I AM FOLLOWER 73 TA1BJ

    • @IMSAIGuy
      @IMSAIGuy  3 ปีที่แล้ว

      Thanks and welcome

  • @k19radio13
    @k19radio13 4 ปีที่แล้ว