How to Build RF Field Strength Meter. (HF VHF UHF) Passive & Sensitive RF Meter.

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  • Опубликовано: 13 янв 2025

Комментарии • 58

  • @crazyham
    @crazyham  6 месяцев назад

    How to Build a Long Range LED RF Meter (Cheap & Easy)
    Link Below :
    ruclips.net/video/hJHk-zmoFBk/видео.htmlsi=ap_3iDpobd3kcKon

  • @izzzzzz6
    @izzzzzz6 2 месяца назад +1

    Very cool. The ones I've seen only have one side of the antenna they probably use the metal enclosure as the counter poise. Would be cool to add a wireless transmitter to be able to see the values from a distance for antenna comparisons etc.

    • @crazyham
      @crazyham  2 месяца назад

      Thank You.
      When one side is only a reference
      (like the chassy)
      then the potential difference between each side is lesser.
      When it has two active (equal and oppsoite sides)
      then each side has a greater potential difference and then it is more efficient.
      I do have more efficient models that use resonance
      yet I haven't published those yet.
      Thanks so much for your comment.
      73 and enjoy experimenting.
      de VK3VKe 🙏⚡🙏

    • @izzzzzz6
      @izzzzzz6 2 месяца назад

      @@crazyham I found a chip that does 92db gain from 1-500Mhz The circuit is very simple and it can run from 2AA batteries or one lithium cell.
      Check out the data sheet on the AD8307
      A youtuber did a really nice circuit diagram and posted a link to it. There is also another version of the chip that covers microwave.
      Check out the video " Relative RF Field Strength Meter "
      Lloyd's Demos
      He has a link to the schema in the description. It's very simple and has some extra features. I would just love to see these be able to transmit data back to a device so you could place it at distance from the antenna for comparisons.
      Finally i would use a jumper board for the chip placed on headers or similar so it could be swapped out for the high frequency version for the occasional experiment.

    • @izzzzzz6
      @izzzzzz6 2 месяца назад +1

      @@crazyham It's nice to have a magnetic loop to be able to use with these. An external antenna connector could allow different types of antenna to be used. The dipole will do almost as good a job at directional detection. If you use screw in telescopic stainless antenna then perhaps it's possible to find or make the female section with solder tab so they can be removable. or even a kill switch for the dipole to be able to use different antenna on an external connector.
      Keep up the good work.

    • @crazyham
      @crazyham  2 месяца назад

      @@izzzzzz6 Excellent ideas my friend. I have recently built an LED RF meter with BNC connectors for interchangeable antennas.
      73 de VK3VKE ⚡🙏⚡

  • @robertdejonge3607
    @robertdejonge3607 Год назад +2

    This is great! Im going to build one to locate antenna / connector / RG-213 cable trouble on marine vhf uhf equipment. Thanks for sharing!

    • @crazyham
      @crazyham  Год назад +1

      Excellent my friend.
      Yeah it will be useful for finding RF on cables etc.
      Let me know how you go.
      73 de VK3VKe ⚡🙏⚡

    • @robertdejonge3607
      @robertdejonge3607 Год назад +1

      @@crazyham I will let you know! ;)

    • @robertdejonge3607
      @robertdejonge3607 Год назад +2

      Received my parts yesterday and hooked it up as follows. I stripped one meter of coax cable ( the one you use for tv). Wrapped the core in a coil arround a small piece of wood (pencil size diameter). The piece of wood has the same length as the meter. For me it is important to be pocket size. Connected one end of the coil to the meter directly and connected the other end of the coil with only 1 resisitor in between to the meter. Tested it with VHF handheld radio (really close by) and it works perfect! To keep everything nice together I covered it with transparant silicone. The complete build is not bigger than the meter itself. For me this will be really useful to find bad connectors, antenna's and RG-214 cables with water intrusion on Marine VHF radio's. Thanks for the idea! 👍👊

    • @crazyham
      @crazyham  Год назад +1

      @@robertdejonge3607 That is Fantastic to Hear my Friend 🙏 Excellent.
      Thanks so much for letting me know too.
      73 de VK3VKe Crazy Ham ⚡🙏⚡

    • @crazyham
      @crazyham  Год назад +1

      @@robertdejonge3607 If you end up putting up a video about your build,
      I would love to see it too ⚡🙏⚡

  • @yurialtunin9121
    @yurialtunin9121 3 месяца назад +2

    Is the speaker cable you use shielded or not? I like your design it is simple and effective.

    • @crazyham
      @crazyham  3 месяца назад

      Yes the cable is covered with some sort of plastic. (Insulated)
      It doesn't have an additional shielding like coax though !
      A simple a two conductor cable that isn't bare copper so it can't be shorted out between the windings.
      Thanks for the question my friend.
      73 from Crazy Ham ⚡🙏⚡

  • @kf5hcr176
    @kf5hcr176 2 года назад +1

    Passive DF,
    Nicely presented

    • @crazyham
      @crazyham  Год назад +1

      Thanks my Friend 🙏

  • @n5yiz
    @n5yiz 2 года назад +2

    cool

  • @KI5WWD
    @KI5WWD 5 месяцев назад +1

    Enjoyed your video and instructions! I am gathering parts to build, and I have 1N34A diodes. Is this OK to use instead of the 1N60P diodes? Also, where in the circuit would you add the potentiometer and what value? Thanks Don KI5WWD

    • @crazyham
      @crazyham  5 месяцев назад

      Hi my friend & thanks for your comment.
      You can connect a potentiometer between either the positive or the negative DC side that leads to the meter terminal. Example, interrupt the connection to the positive terminal of the meter with a potentiometer.
      I suggest approx 100K ohm Potentiometer.
      I suspect the 1N34A diodes would give a similar result but I suspect that a genuine 1N60P germanium diode might be a tad more efficient at higher frequencies but I am not 100% sure.
      Be careful as there are plenty of fake 1N60P diodes for sale that are really Silicon diodes.
      (You can also leave out the inductor if you want as it is a little bit of overkill. It was to ensure that the system only worked as a dipole.
      It will still be sensitive and useful without the inductor.)
      Let me know how you go with the project mate
      & 73 from Australia 🇦🇺

    • @crazyham
      @crazyham  5 месяцев назад

      PS: Take a look at my latest video
      on how to build a sensitive LED RF field strength meter :
      ruclips.net/video/hJHk-zmoFBk/видео.htmlsi=5bHeZJGtLodY2gSA

    • @KI5WWD
      @KI5WWD 4 месяца назад +1

      @@crazyham Finished building and testing -works great! I didn't need to use the 100k pot, and the 1N34A germanium diodes seems to work well. I used it as a "show and tell" at our local ham meeting today and the response from the members was loaded with questions! I referred them to your You Tube website, but I had to take the back of the box apart to show them the actual components. Our president was fascinated using his HT at various positions and angles and viewing the results. I used a large 100 micro amp meter, the 4 IN34A germanium diodes, a plastic box, and parts of "rabbit ear" TV antenna. Aprox $27 Thanks for giving the world a great, easy project! 73 Don

    • @crazyham
      @crazyham  4 месяца назад

      I'm so pleased that you had a great success with the project Don.
      That is awesome the club members were very interested too.
      I really appreciate you coming back to share your outcome too.
      Maybe you can build the next one for show and tell at the Club too?
      it is an LED rf meter.
      It is my latest video on RUclips.
      Thanks again Don.
      73 de VK3VKe (Epoch)
      ⚡🙏⚡

  • @mrobarton7192
    @mrobarton7192 2 года назад +2

    Good job mate! Anything special about the germaniums other than low forward bias voltage? Can you use Schottky diodes?

    • @crazyham
      @crazyham  Год назад +1

      I just noticed my reply isn't showing but I am certain I replied some time ago.
      Schottky should work fine, But I suspect the Germaniams will work better for this 🙏

  • @seniorchief48
    @seniorchief48 9 месяцев назад +2

    What is the function of the toroid?

    • @seniorchief48
      @seniorchief48 9 месяцев назад +1

      Answered my own question by paying attention to the teacher. . .🤣

  • @josealonsorodriguezsalaice3232
    @josealonsorodriguezsalaice3232 Год назад +1

    kool video ,mtr crazy ham

    • @crazyham
      @crazyham  Год назад +1

      Thank You My Friend ⚡🙏⚡
      Check out my recent videos on a Simple Common Mode Current Meter 🙏

  • @partsguy9423
    @partsguy9423 4 месяца назад +1

    Would there be a way to attenuate the signal?

    • @crazyham
      @crazyham  4 месяца назад

      Yes, You can place a potentiometer between the Positive side that connects to the meters positive terminal. (100K OHm or higher).
      If you look up my latest video on how to build an led rf meter
      it shows how to connect the potentiometer.
      It has a similar circuit except for the LED Board & an On Off Switch.
      Link Below:
      ruclips.net/video/hJHk-zmoFBk/видео.htmlsi=ap_3iDpobd3kcKon

  • @hulkgqnissanpatrol6121
    @hulkgqnissanpatrol6121 Год назад +1

    I'm so in over my head in my journey in radio's and Rf frequency tuning ect that I'm getting to a place in my head that is conflicting with everything I'm reading online as most articles are by enthusiasts that have their own way's.
    I can't learn like that. Does anyone have any online book recommendations? Preferably free PDF? 🤔
    Thanks for this. I saved it foe later experiments, can it be used at the receiver end instead?

    • @crazyham
      @crazyham  Год назад +2

      Hi my Friend.
      This type of passive (un-amplified) meter is only good for being close to a transmitting antenna and would be too insensitive for a receiver in the distance .
      The whole world of Radio has many rabbit holes and some of them are never ending as we still don't know everything in the world of physics.
      It's best to figure out what you personally want to achieve and then take it from there &
      If you are wanting to become a radio Ham then here in Australia we have the Radio & Electronics School of Australia which is a Helpful Online Resource
      & there would be many other helpful resources in different parts of the world too.
      If in Australia, here is the link to the RES
      res.net.au/
      and if in the USA I would look up the ARRL and see what they can offer
      or in UK look up RSGB.
      Personally I would suggest to take everything one step at a time
      & at your leisure.
      Best Regards mate & I wish I could have been more helpful.

    • @hulkgqnissanpatrol6121
      @hulkgqnissanpatrol6121 Год назад +1

      @@crazyham more than helpful mate thanks heaps, I'll definitely look into that link and might even see if the local club is doing any meets at the repeater on Mt tassie.
      Thanks again mate

    • @crazyham
      @crazyham  Год назад +1

      @@hulkgqnissanpatrol6121 Ok, Excellent , I wasn't sure if you were VK based or not.
      I can Vouch for the RES
      & Ron Bertrand , The Founder is an Awesome Human Being.
      It is Totally None Profit
      and all in the interest of those interested in the field of electronics and radio.
      73 my friend ⚡🙏⚡

    • @hulkgqnissanpatrol6121
      @hulkgqnissanpatrol6121 Год назад +1

      @@crazyham VK3BEZ is the club call sign. Thanks again mate

    • @crazyham
      @crazyham  Год назад +1

      Are you a member
      & would you say they are a good club?
      I haven't gave clubs much thought in recent years
      but it would be nice to connect with other like minded folks.
      Where is the Club Based ?

  • @mohammadalfauomey3443
    @mohammadalfauomey3443 Год назад +1

    What is the value of the capacitor ?
    Thanks

    • @crazyham
      @crazyham  Год назад +1

      Hi there, if you choose to use a capacitor, it's best to have a very low value to avoid meter lagging.
      Maybe around 10pF or less
      But it works fine without any additional Capacitor added.
      I don't recall the exact value I had on this one as it's not at all critical.
      You could for example use 1uF instead of pF but they are larger.
      If you go too high in value it takes more time to charge the cap and dampens the meter movement.
      73 my friend ⚡🙏⚡

  • @chriskopec1858
    @chriskopec1858 2 года назад +1

    ❤👍🐺

  • @osamafarg9895
    @osamafarg9895 2 года назад +1

    Please, diode 4148 can work?

    • @osamafarg9895
      @osamafarg9895 2 года назад +1

      What value of capacitor, and thanks for your replying

    • @crazyham
      @crazyham  Год назад

      It seems my reply has disappeared.
      I am sure I replied some time ago lol.
      I am not sure about the diode your referred to. The capacitor isn't critical, but a very low value would be ok, or even no capacitor should be fine as there is some none linear capacitance across the 4 diodes. 🙏

  • @CLMSF25
    @CLMSF25 10 месяцев назад +1

    BUT HOW NO ELECTRIC A WORK?

    • @crazyham
      @crazyham  10 месяцев назад

      I'm sorry, I don't understand your Question ?

    • @Pelixu
      @Pelixu 10 месяцев назад +1

      I have an idea of what they're saying, " how is it working without any electricity?" ​@@crazyham

    • @crazyham
      @crazyham  10 месяцев назад

      Thank You 🙏
      The antenna elements receive the rf signal and the diodes rectify the alternating currents into direct currents to drive the meter 👌⚡👌

  • @dtmty
    @dtmty 2 года назад +1

    i wish to buy one of this, how do i can get one? or a reference item on ebay / amazon ?

    • @crazyham
      @crazyham  2 года назад +1

      Hi my Friend.
      What are you looking to Buy?
      This is a how to Build video and the components required are very inexpensive.

    • @dtmty
      @dtmty 2 года назад +1

      @@crazyham yes indeed, and also is cheap to purchase a new one, but what I would have better to also know the frecuency. so not just strenght but also HF related to the strenght

    • @crazyham
      @crazyham  2 года назад

      @@dtmty I suggest buying a cheap pocket oscilloscope and adapt an antenna with a suitable bnc connection to connect to the scope
      and then you have full info including frequency, magnitudes etc and a very broad range.

    • @crazyham
      @crazyham  2 года назад +1

      Of course , it depends on what frequency range you are interested in.
      I mostly play with HF and find this little thing very good for HF.
      au-m.banggood.com/MUSTOOL-MDS120M-Professional-Digital-Oscilloscope-120MHz-Analog-Bandwidth-500MS-or-s-Sampling-Rate-320x240-LCD-Screen-Support-Waveform-Storage-with-Backlight-p-1759856.html?gmcCountry=AU&PLA-AU-all-220415-massa¤cy=AUD&cur_warehouse=CN&createTmp=1&ad_id=593197213431&gclid=EAIaIQobChMIvL35p9ia_AIVVAQrCh2bqwEQEAQYASABEgK01_D_BwE

    • @dtmty
      @dtmty 2 года назад +1

      @@crazyham thank you a lot, I really appreciate your reply

  • @DE-ke2rf
    @DE-ke2rf 8 месяцев назад +1

    .001 uf cap should be ok.

    • @crazyham
      @crazyham  8 месяцев назад

      Yes,
      absolutely.
      Or No added Cap is fine too.
      I have used as high as 1uF without too much lag though from experience there is no need for a cap at all.