AmRad Podcast
AmRad Podcast
  • Видео 33
  • Просмотров 1 056 889
SWR OK, But Nobody Can Hear me?
I recently had an issue where tuning my antenna at the shack gave a 1:1 SWR, but I was barely getting out calling CQ. Measuring directly at the antenna showed resonance where I expected, but at the choke-side, no resonance at all! Could it be water in the coax? Could it be a faulty choke? Let's dig in!
Просмотров: 1 135

Видео

Doorknob Capacitor 20/40m Trap Antenna
Просмотров 5 тыс.Год назад
My experimental coax-based 20/40m trap vertical antenna has finally bitten the dust. Now it's time to replace it with a proper discrete capacitor-inductor trap. So in this episode I touch on the subject of putting the trap together, show how I put it together, and we do a quick test on the RigExpert. Some other issues are uncovered, that will no doubt make it into the next episode, so come on b...
Installing Coax from Shack to Antenna
Просмотров 6 тыс.2 года назад
Today I'm finally installing my direct burial LMR-400 from my radio, up into the attic, down the outside of the house, and finally underground. I show a goofy tool I hacked together to make slits in the ground in order to run the coax, and show some of the components that make up the lightning arrestor at the base of the house. It is a much needed improvement over the noisy attic dipoles for sure!
Taking the DX Commander Multiband Antenna for a Spin
Просмотров 5 тыс.2 года назад
Callum over at DX Commander sent me a “Commander Classic” to have a play with. In this video, I go through some of the assembly, and test it out with a little WSPR and FT8. Short story, I liked it so much, I’m going to replace my DIY antenna with it. Callum's Channel: ruclips.net/channel/UCEWRZEIjVQB8aUkyUQ-g-zA Mike's Channel: ruclips.net/user/Hollyend1 Our chat on HF Verticals and Magnetic Lo...
Self-resonant Trap - No Capacitor?
Просмотров 11 тыс.3 года назад
I wanted to turn my monoband 20m vertical into a dual band 20/40m antenna by installing a trap. A little bit of theory, a build, and of course some testing. The theory here applies to multiband dipoles as well. Follow more stuff here: @tcurrentsource www.thecurrentsource.com
Repair of a Dynamic Signal Analyzer (HP3562A)
Просмотров 1,8 тыс.3 года назад
I have a sick dynamic signal analyzer that needs some TLC. I try to find an intermittent fault that causes the source to output gibberish instead of a nice clean sine wave.
Marantz 2220B Restoration
Просмотров 4,4 тыс.3 года назад
Restoring old radios can be fun and rewarding, or it can be a dusty horror show. This one's a bit of both. The Ol' Marantz calls for recapping everything in the signal path, as well as the power supply. We replace a majority of the small-signal transistors, DeoxIT the potentiometers and switches, relamp the incandescent bulbs with LEDs and she even gets a new pair of kicks. Finally, the power a...
Building an HF Vertical 1/4 Wavelength Monopole
Просмотров 41 тыс.3 года назад
Today I'm building an HF monopole for 20 meters. I go through a basic formula, for fun we model the antenna in MMANA-GAL, then I show you how I put it together and tune the elements. Stick around until the fireside chat at the end, and I talk a little bit about ground-mounted vs. above-ground monopoles.. and proximity to trees. This should be a lively debate in the comments section ;) Follow mo...
Measure Cable Length with an Oscilloscope
Просмотров 5 тыс.3 года назад
Today we take a crack at measuring some coax cable using TDR on an oscilloscope with the help of a pulse generator. Cable length can be calculated by sending a pulse down a cable and measuring how long it takes for the pulse to return. If you don't have a pulse generator, here are a couple of cool little circuits from fellow RUclipsrs: Mr. Carlson's Lab TDR: ruclips.net/video/I1gfUNh5PJQ/видео....
DIY High Voltage Variable Capacitor
Просмотров 35 тыс.3 года назад
Prompted by the need for a high voltage variable capacitor to tune an (magnetic loop) antenna, I go through the calculations on how to make one using single sided PCB blanks. We also take a look at calculating capacitance using air and mixed dielectric materials. Follow more stuff here: @tcurrentsource www.thecurrentsource.com
Hardline RF Power Divider v2.0
Просмотров 7 тыс.4 года назад
This is the second attempt at making an RF power divider (and the second attempt at uploading this video). If you haven’t been following along, I’ve decided to make a couple of high gain antennas for the 70cm band and need to split the power between them. So what better way than to make your own power divider! I go through what I did wrong the first time and how to test and measure the performa...
Make a 1/4 Wavelength Antenna + Calculations
Просмотров 45 тыс.4 года назад
Today I’m going to show you how to make a 1/4 wavelength antenna for the 70cm amateur radio band. Of course physics doesn’t care who’s using her laws, so this design can be applied to really any frequency, though the lower in frequency you go, the bigger it gets! We’ll cover a little basic antenna theory, build it, install it in the attic and do some testing & tuning on a nanoVNA vector network...
Hardline Coax RF Power Divider
Просмотров 14 тыс.4 года назад
This video is a kind of, "Here's what I'm working on" - I don't explain everything, but "let's hang out and make something while we all have cabin fever". Now, I'm no RF expert, but I've been dabbling in amateur radio for quite some time. The latest effort is setting up an EME (moonbounce) station. I need to make a power divider to split the RF between two stacked yagi antennas. In this video I...
45) Solder Surface Tension and Why You Should Care
Просмотров 49 тыс.5 лет назад
Support: www.patreon.com/thecurrentsource Twitter: TCurrentSource Web: www.thecurrentsource.com/ I have a PCB design that’s been giving me some trouble during the reflow process. That got me thinking, surface tension of solder is a pretty interesting and useful thing. In this video, I look at what surface tension is, how it’s useful and some of the problems that it can create. So co...
43) Junk Box Current Source
Просмотров 2,9 тыс.5 лет назад
I finally built a permanent-solution current source, albeit from my junkbox, but at least now I have something to pull off the shelf as I need it. There need to be some refinements, however hopefully it inspires you to make your own out of an LM317 adjustable regulator IC. I’ll show you roughly how I made it and why such a device is useful. We’ll use it in future videos to analyze band theory o...
42) Make a Rack Enclosure For Your Test Gear
Просмотров 9 тыс.5 лет назад
42) Make a Rack Enclosure For Your Test Gear
39) Electronic Components vs. 1.5kV
Просмотров 1,7 тыс.6 лет назад
39) Electronic Components vs. 1.5kV
38) Repairing a 4,000 Volt Power Supply
Просмотров 4,1 тыс.6 лет назад
38) Repairing a 4,000 Volt Power Supply
37) Contact Bounce & Mitigation
Просмотров 8 тыс.6 лет назад
37) Contact Bounce & Mitigation
36) DIY TEM Cell for EMC Pre-Compliance Testing
Просмотров 14 тыс.6 лет назад
36) DIY TEM Cell for EMC Pre-Compliance Testing
35) Part3: RocketCam Gets a New PCB + Pan/Tilt Testing
Просмотров 1,5 тыс.6 лет назад
35) Part3: RocketCam Gets a New PCB Pan/Tilt Testing
34) Part2: RocketCam Power Up & Repair(?)
Просмотров 1,8 тыс.6 лет назад
34) Part2: RocketCam Power Up & Repair(?)
33) Part1: Teardown Pan / Tilt RocketCam Project
Просмотров 2,2 тыс.6 лет назад
33) Part1: Teardown Pan / Tilt RocketCam Project
31) Acrylic Bending for Electronics Enclosures
Просмотров 19 тыс.6 лет назад
31) Acrylic Bending for Electronics Enclosures
30) Op-Amps vs. Comparators
Просмотров 4,8 тыс.6 лет назад
30) Op-Amps vs. Comparators
29) Non-Invasive Power Failure Monitor
Просмотров 7 тыс.6 лет назад
29) Non-Invasive Power Failure Monitor
27) Four Wire Kelvin Resistance Measurement
Просмотров 9 тыс.6 лет назад
27) Four Wire Kelvin Resistance Measurement
25) Driving Inductive Loads via RPi or Microcontroller
Просмотров 3,4 тыс.7 лет назад
25) Driving Inductive Loads via RPi or Microcontroller
24) Linear Variable Differential Transformer (LVDT) & Coefficient of Coupling
Просмотров 28 тыс.7 лет назад
24) Linear Variable Differential Transformer (LVDT) & Coefficient of Coupling
20) DIY Stomp Box Build + Analysis
Просмотров 2,2 тыс.7 лет назад
20) DIY Stomp Box Build Analysis

Комментарии

  • @SimonsRadioSpam
    @SimonsRadioSpam 10 дней назад

    I think you mean millimetres not centimetres 😬

  • @bussi7859
    @bussi7859 17 дней назад

    A moron that makes crappy uploads to get a few cents from RUclips I’m 75 now and got my ham radio certificate when I was 16 I built a few rigs in my life and have a lot of friends that also are builders, This is absolutely stupid waste of time.

  • @bussi7859
    @bussi7859 17 дней назад

    What an ignorant person, I’m not allowed to say other words that sauté better

  • @bussi7859
    @bussi7859 17 дней назад

    For crap sake, you are inventing the wheel all over again, high voltage variable capacitors are on eBay some of them are vacuum capacitors for 20kV 25pF to 1500pF, what is wrong with you?

    • @AmRadPodcast
      @AmRadPodcast 17 дней назад

      I'm not inventing anything. I'm using what I had on hand to make an alternative. You clearly didn't listen to what I had to say in the video. Pay attention. So glad I'm not making these videos anymore so I don't have to listen to armchair quarterbacks put their two cents in every day. Don't like what you see? Go watch someone else.

  • @pasadenaphil8804
    @pasadenaphil8804 20 дней назад

    I'm late discovering this video but I am about to recap my 2220B this weekend. I've already cleaned out the pots (this greatly improved the sound and removed most of the scratching) and re-lamped all but the dial and stereo indicator light (LED is too bright). My only question is: how do you determine that transistors need to be replaced and which ones? Thanks. Great job with the video.

  • @jasonf9736
    @jasonf9736 22 дня назад

    Nice video and good craftsmanship on the antenna build, Derek. If you enjoyed the lower recieve noise, just wait until you throw a 20 meter mono band yagi on top of a 40 foot tower! I was blown away at how quiet it was compared to my ground mounted hustler 5BTV. Speaking of the 5BTV, I recently relocated it to 16 foot above ground and following manufacturers installation recommendations, ran several tuned "raised" radials for each band of interest. It worked fine, and was quieter than when on the ground, but not much. I then moved it to 12 foot above ground and attached the 10 foot rigid steel mast to my RV's bumper and a unistrut bracket at the roofline, mast not touching the earth. I then bonded my radial plate to the metal skin of the RV and completely removed the raised wire radials. This is working extremely well and dare I say BETTER than any combination previously used. SWR is < 1.5 on all bands except for 40 meters, which is at 1.7. The takeoff angle must be better for DX than before, due to the locations of contacts I have made now compared to being ground mounted. I haven't tried to model it due to not having the program yet, but I will try to download the modeling software you gave the link to in the description, although, Im not sure if it's possible to model a 30' RV as a radial field. 😅 Anyway, thanks again for taking the time to document and explain things! Experimenting is truly the best part of the hobby, or at least it is for me. 73 DE KN6UIZ

  • @daRealGamer22
    @daRealGamer22 Месяц назад

    Thumbs up just for the Ukraine patch 👍 🇺🇦 Thanks for your support

  • @keithtreisch6890
    @keithtreisch6890 Месяц назад

    Love the video. I have been doing experumenting with j poles fopper and ed fond pvc style. Just built a quarter wave and i love it. I ned to revise how i did mine a little but love the video. Straight to the point and simpke.

  • @lmp2208
    @lmp2208 Месяц назад

    Thanks for technical explanation. Much appreciated. However, no doubt you realise by now (3 years ago ?) that you slipped a decimal place in your calculations. At 8:00, up pops the line with 1/4 wave length calculation. 0.172 metres should be 17.2 cm …. they don’t cal it “centi” for nothing 🙂 ….. or you could have left it as mm. Assume you’re USA, so maybe you’re use to using Imperial units, and are metrically “challenged”. 😆 I’m from Australia. I read down thru the first 20 comments or so, on my iPhone and couldn’t see any pick-up on this point so posting. I notice one commentator was Canadian (metric), but no mention ?

    • @lmp2208
      @lmp2208 Месяц назад

      Ok … I should have kept watching … corrected. Perhaps you should have subtitled the correction immediately instead of waiting 45 secs in the video, and then only leaving it up for 10 secs.

  • @Rabbit.760
    @Rabbit.760 2 месяца назад

    I hate rosin core solder... it fucks me off cuz im not that good at soldering to begin with. However I've found that one drop of 85% phosphoric acid diluted 5 to 1 works wonders. Dip the tip in the acid before tinning and a couple drops in my flux is the shit

  • @franc_ea6fs
    @franc_ea6fs 2 месяца назад

    Excellent job, dear OM. Many thanks for sharing!

  • @michanoymark2109
    @michanoymark2109 2 месяца назад

    Where is the video summarizing that the problem has been solved?

  • @JohnSmith-wl8cv
    @JohnSmith-wl8cv 3 месяца назад

    Why do Americans leave out the ketter T in inter they say inernet 😂 mobile not moble solder not soder

  • @JohnSmith-wl8cv
    @JohnSmith-wl8cv 3 месяца назад

    There are online antenna calculators to work out the measurement of antennas ,just go tell us the measurements, never mind the science lesson get on with ,,I skipped to half the video

  • @jamesryan6370
    @jamesryan6370 3 месяца назад

    Lost me with the Ukraine flag shirt...

  • @eagleviewhd
    @eagleviewhd 4 месяца назад

    are the radials 183 cm total lengtth, before being bent?

  • @user-kn4wv2wf1q
    @user-kn4wv2wf1q 4 месяца назад

    VERY GOOD VIDEO

  • @72chargerse72
    @72chargerse72 4 месяца назад

    Very well explained. Thanks for takeing the time.

  • @mroe34
    @mroe34 4 месяца назад

    Enjoyed the video. Which vertical antenna did you install? Thanks.

  • @williammarkley1037
    @williammarkley1037 5 месяцев назад

    It’s looking good though

  • @williammarkley1037
    @williammarkley1037 5 месяцев назад

    As long as your soldered inner conductor to tube you should be good

  • @williammarkley1037
    @williammarkley1037 5 месяцев назад

    But you can make the that way too

  • @williammarkley1037
    @williammarkley1037 5 месяцев назад

    I dont think that wires has to be there as long as you touch the tube with center of pl 239,s or whatever your useing and have it soldered that’s all that matters

  • @seniorchief48
    @seniorchief48 5 месяцев назад

    KF0OIY….. “*@#’&&*)(“ you made me understand antenna math.

  • @dsmith004
    @dsmith004 5 месяцев назад

    Just found your channel. I find the math helps me understand the design and modifications of an antenna.

  • @subdynoman
    @subdynoman 5 месяцев назад

    Absolutely BEAUTIFUL! Such a fantastic display of the marrige of math, geometry, pyshics and electronics. And it all begins to feel more intuitive. It brings my world of acoustic transmission to life.

  • @tvdylan
    @tvdylan 8 месяцев назад

    if i want to make a higher capacity capacitor, aka more pico farrads, whats the approach ? just add more plates and larger surface area ? very nice construction you have !! well done ! im experimenting with resonance ! and looking to atain a use'able variable capacitor with say 0-1000 pf or more. but i think 1000 pf is a good start.

  • @sawdustjohnny
    @sawdustjohnny 8 месяцев назад

    Nice one, the explanation at 11.55 minutes in is really helpful.

  • @bjmaratonista
    @bjmaratonista 8 месяцев назад

    Greetings from Colombia. I am new in ham radio, I want to make and install my own antenna for 20 meters band, and I don't see all the real dimensions of your antenna and others details. Why two holes? What is the diameter of your antenna? What material is using for that? Exactly how meters tall? Why 3 radials instead of 1 radial? If you offer this details in a blog, please tell me the link. 73!

  • @mikeramsey9747
    @mikeramsey9747 9 месяцев назад

    First one of your videos that I have caught and your monopole sounds like an interesting build and the performance comparison to your attic antenna was informative.

  • @56pavel53
    @56pavel53 9 месяцев назад

    👍

  • @johnpetters
    @johnpetters 9 месяцев назад

    Great presentation. Many thanks. De G3YPZ

  • @aerofart
    @aerofart 10 месяцев назад

    You make good videos. Why did you stop?

    • @AmRadPodcast
      @AmRadPodcast 10 месяцев назад

      Thanks. I've been making electronics videos for element14.. that plus the "real" job, doesn't leave much time. I hope to have more time this year so will probably get back to it.

  • @alrubio4401
    @alrubio4401 10 месяцев назад

    Noticed your Yaseu FT710..... I have one and love it... Go work on the antenna attic run.

  • @E57det7I
    @E57det7I 10 месяцев назад

    It is a violation of FCC regulation for a homeowners association to require or attempt to stop a resident building and operating ham radio, and all of its required instruments, including antennas. It is considered an emergency communication method, and any local authorities that attempt to prevent a licensed ham operator from operating are in open violation of federal law. Regardless of any HOA agreements.

  • @py2rpjrubens450
    @py2rpjrubens450 11 месяцев назад

    FJ OM! TNX for sharing! My TS-440AT have dots in display! 73

    • @AmRadPodcast
      @AmRadPodcast 11 месяцев назад

      Dots are an easy fix if you have tweezers and a bucket load of patience.

  • @sobamani1244
    @sobamani1244 11 месяцев назад

    Well done 👍👍👍

  • @michaelanasakta2378
    @michaelanasakta2378 11 месяцев назад

    Thank you so much. I will copy this in full. Could you please post a brief video of your completed and installed capacitor? I am sure many of us would like to see it in action and so learn even more.

  • @Dave_____
    @Dave_____ Год назад

    There is a gentleman that makes replacement LCD screens for the HP3562A

    • @AmRadPodcast
      @AmRadPodcast Год назад

      I’ve seen them and they look fantastic, but I think around $400 last I checked… someday.

  • @paulziminskin2ghr282
    @paulziminskin2ghr282 Год назад

    A weller soldering gun works well for this ..

  • @stephenwalters9891
    @stephenwalters9891 Год назад

    Considering how much space you have in your attic you could install a dual band slim-jim or a 7/8 vertical or a j-pole. at 70cms you can get some serious gain from a vertical G7VFY

  • @JA-fy1bn
    @JA-fy1bn Год назад

    Very informative. Thanks!

  • @adriancressy8363
    @adriancressy8363 Год назад

    I have the Rapide and my 15m band is not very good. Barely got to 2:1 SWR. 10M was a little squirrly. 20M and 40M great match. 17M reasonable.

  • @Chickendoc
    @Chickendoc Год назад

    Sweeeeeet build and video - give us another helping!

  • @80lab38
    @80lab38 Год назад

    thumbs up for reverse umlauts!

  • @mrderekbarthow5967
    @mrderekbarthow5967 Год назад

    For your four ground plane radials is the measurement from the edge of the aluminium base? Or do you measure from the edge of the So239 socket? They are significantly different numbers. Thanks Derek ZL1DCB

    • @AmRadPodcast
      @AmRadPodcast Год назад

      The aluminum plate is part of the ground plane, so should be included.

  • @seeharvester
    @seeharvester Год назад

    I'm guessing that burying the cable helps to quiet down your noise floor too.

  • @longrider42
    @longrider42 Год назад

    Question, and I hope you will answer me. I have a Diamond 7900 Super Gainer 7/8 wave 2m/70cm antenna, which says on the site where I bought it "Does not require ground plane" But I am planning on using this antenna for Field day, on a 12 foot tall mast. What I want to know, is if I added a ground plane to it, would it help? And if so how long do I need to make the radials. I have been trying to find an answer to this, with no luck. I'm lucky, I live in a HOA controlled mobile home park. But one of the board member is also a ham. So I had no problem putting up a Arrow Open Stub J-pole, on a 15 foot mast. Hey you never know till you ask.

  • @dmgx
    @dmgx Год назад

    Great info. Well explained.