How to Build RF Field Strength Meter. (HF VHF UHF) Passive & Sensitive RF Meter.
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- Опубликовано: 28 авг 2024
- Updated (LED) version here :
• How to Build a Long Ra...
Also you can ignore the inductor on this video.
Any advantage is minimal.
Follow all instructions and leave out the inductor.
Originally I placed the inductor to ensure differential mode currents, yet I have since confirmed that using the diode scheme I have suggested that the majority of RF currents will only flow under similar circumstances anyhow & there will be minimal common mode currents.
We live and we learn 🙏
73 de VK3VKe 💡
(This is one of my Methods for building a
passive yet sensitive RF field strength meter for HF , VHF and UHF
I am sure you can build a much nicer looking version.
This is just showing the basic fundamental circuit design.
Make sure that you determine which terminals are pos and neg on your panel meter.
(You could add a variable resistor to vary the meter sensitivity.)
Here are links to the components required.
L8 Torroid
www.jaycar.com...
Panel Meter
www.ebay.com.a...
1N60P Germanium Diodes
www.ebay.com.a...
Feel free to check out what else I am upto.
• ⚡📡RF Longitudinal Magn... )
Consider building my newer design here :
• How to Build a Long Ra...
How to Build a Long Range LED RF Meter (Cheap & Easy)
Link Below :
ruclips.net/video/hJHk-zmoFBk/видео.htmlsi=ap_3iDpobd3kcKon
This is great! Im going to build one to locate antenna / connector / RG-213 cable trouble on marine vhf uhf equipment. Thanks for sharing!
Excellent my friend.
Yeah it will be useful for finding RF on cables etc.
Let me know how you go.
73 de VK3VKe ⚡🙏⚡
@@crazyham I will let you know! ;)
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! 👍👊
@@robertdejonge3607 That is Fantastic to Hear my Friend 🙏 Excellent.
Thanks so much for letting me know too.
73 de VK3VKe Crazy Ham ⚡🙏⚡
@@robertdejonge3607 If you end up putting up a video about your build,
I would love to see it too ⚡🙏⚡
Passive DF,
Nicely presented
Thanks my Friend 🙏
cool
kool video ,mtr crazy ham
Thank You My Friend ⚡🙏⚡
Check out my recent videos on a Simple Common Mode Current Meter 🙏
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
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 🇦🇺
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
@@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
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)
⚡🙏⚡
Good job mate! Anything special about the germaniums other than low forward bias voltage? Can you use Schottky diodes?
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 🙏
❤👍🐺
Would there be a way to attenuate the signal?
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
What is the function of the toroid?
Answered my own question by paying attention to the teacher. . .🤣
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?
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.
@@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
@@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 ⚡🙏⚡
@@crazyham VK3BEZ is the club call sign. Thanks again mate
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 ?
What is the value of the capacitor ?
Thanks
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 ⚡🙏⚡
Please, diode 4148 can work?
What value of capacitor, and thanks for your replying
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. 🙏
BUT HOW NO ELECTRIC A WORK?
I'm sorry, I don't understand your Question ?
I have an idea of what they're saying, " how is it working without any electricity?" @@crazyham
Thank You 🙏
The antenna elements receive the rf signal and the diodes rectify the alternating currents into direct currents to drive the meter 👌⚡👌
i wish to buy one of this, how do i can get one? or a reference item on ebay / amazon ?
Hi my Friend.
What are you looking to Buy?
This is a how to Build video and the components required are very inexpensive.
@@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
@@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.
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
@@crazyham thank you a lot, I really appreciate your reply
.001 uf cap should be ok.
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.