2 Dollar Radiation Detector You Can Build. Beware of imitation diodes that don't have an H on them.

www.tvrepairin...
In this video I demonstrate how you can build a simple Radio Frequency Detector using only a detector diode and an LED. This simple circuit was sensitive enough to operate from my cell phone, my WIFI router, my walkie talkies, my microwave, my smart meter, my google assistant, and any other devices with enough power that transmit in the frequency range of my resonant antennas.
Here is a warning about using some aftermarket diodes that may not work in this project. In this video I used the 1SS86 Diode which worked well, but beware that unless the diode is made by hitachi, it may not work on the higher frequencies. Thanks to a viewer I've also learned that the 1N5711 also works.
• Inferior Diodes to bew...

[@GrantsPassTVRepair]

Here is a warning about using some aftermarket diodes that may not work in this project. kzbin.info/www/bejne/nZnZYn2vn7x1bq8

[@lucase6407]

Great project! Used this to make "On Air" LED lights on my door that are completely passive for my 2m ham radio @ 25w.

[@arsbadmojo]

That is cool!

[@GenaTrius]

So it's literally just a couple of crystals and some wire receiving vibes. Incredible

[@stargazer7644]

3:38 There's about a thousand watts of 2.5 GHz power on the other side of that microwave oven door. That's +60 dBm. The case on a microwave is only about a 30 dB attenuator. That reduces the 1000 Watts down to about 1 W radiated (30dBm) total. That's about 10 times what your WiFi router puts out. The reg is 21 CFR 1030.10 which limits radiation of an oven in your home to 5 milliwatts per square centimeter at any point 5 cm from the case of the oven. The window on the door of my microwave oven could radiate 3W and meet that legal requirement.

[@uploadJ]

Upvoted.

[@programmer1111x]

how would you know the case on a microwave is only about a 30 dB attenuator?

[@stargazer7644]

​@@programmer1111x You can measure it with a spectrum analyzer. The manufacturers only make them as good as they need to to meet the regs.

[@cyberyogicowindler2448]

Thanks. I love it! What I like is that this is very physical and unlike obscure expensive EMF meters made in China contains no chips to cheat you or pretend anything what isn't there. In 1990th with the first cellphones there was a hype with phone ring indicators consisting of a keychain with a red LED in clear acrylic plastic, which likely works the same. Also microwave oven leak detectors only contain some kind of diode attached to a moving coil instrument.

[@morpher44]

Next step. Make them for 5G ... say 28Ghz ... 10mm for full-wave, and then approach a 5G tower and see how close you need to get to light them.

[@ahmetmutlu348]

Actually this signal is too high enough to use directly witg arduino mostlikely or atleast with one transistor amplifying... which means this data can be used for recording signals from that frequency.. but mostlujely will need lots of filtering if connected to something else ewen if indirectly or close..

[@uploadJ]

re: "how close you need to get to light them." Heh. And bring a ladder. Heh. Verizon puts these pretty high up on power poles (not ground level).

[@morpher44]

@@uploadJ well the paranoid claim about 5G is that the radiation from them will destroy human DNA. Also, these towers are smaller, lower to the ground, and there are more of them as compared to older cell phone 4G, 3G, etc.

[@stargazer7644]

@@ahmetmutlu348 Who has said anything about an arduino? This is a UHF diode and an LED.

[@ahmetmutlu348]

​@@stargazer7644Led turns on that means around 2v and lots of m.amps which means can be driven tough cheap circuits.. but noise mostlikely will require filtering,as arduinonlike big metal things will act as antenna too..

[@JuanSanchez-ik7wx]

When I worked for the power company we used RF detectors to locate buried power lines. But it ended locating more water lines that were grounded than power lines. LOL

[@dand5593]

Great vid, this toghether with a energy harvester will power a iot sensor easy. Thanks!

[@danko6582]

If you could make them for 121.5MHz you could sell them for 10-20 bucks in aviation stores as novelties to monitor the blind guard.

[@GrantsPassTVRepair]

Can you tell me what the blind guard is?

[@bjornroesbeke]

@@GrantsPassTVRepair It's _a frequency used on the aircraft band reserved for emergency communications for aircraft in distress_. en.wikipedia.org/wiki/Aircraft_emergency_frequency

[@GrantsPassTVRepair]

@@bjornroesbeke Thanks for the information.

[@stargazer7644]

That would only work if the aircraft was sitting in your house with you. These aren't going to pick up transmitters more than a few feet away.

[@stargazer7644]

Red LEDs have much lower forward voltage requirements so would be more sensitive.

[@johangoethe2472]

Congratulations Grants Pass. You made a very proffesional work. The best ever. Let me try to reproduce it and come back again to ask you some issues if they appear.

[@richardhz-oi8px]

This is one of your most interesting presentations yet, really makes me realize how important antenna element length is. Perhaps this is why you had such trouble finding the "perfect" television antenna as you described in one of your earlier videos, since all the different translators are on different frequencies in different areas.

[@GrantsPassTVRepair]

Using the correct antenna is important, but one of the other problems I've encountered in this area are multi path reflected signals bouncing off mountains, and arriving at my TV out of phase with the signal which originates at the transmitter. In one case I got better reception from a weaker signal than I did a stronger signal due to the multi path reflected signals.

[@richardhz-oi8px]

@@GrantsPassTVRepair I guess a pretty high degree of directionality is needed to try to block out reflections(or choose the best one).

[@stargazer7644]

This is why quality TV antennas are wide bandwidth log periodic designs.

[@danthemann6565]

Cool video, got lost reading and writing in the comments. Thanks, from Hoboken New Jersey.

[@ahmetmutlu348]

Well by adjusting to correct frequency and uaing a optocoupler or transistor it can do wery sensitive detections ... i guess transistor will cause lots of noise from source voltage so using photo resistors this means extreemely sensitive signal tracker... with correct decoder this might end up to be all range signal tracker ... worth a try ..

[@robertcalkjr.8325]

Interesting! Thanks Dave!

[@domsoverthetop]

5:52 Comrade Dave: "Hey google" 6:00 Evil Google : 'Sorry, I'm busy listening in on your family while they insult China'.

[@GrantsPassTVRepair]

I think they would find most of my conversations pretty boring, but I generally keep the little gadget unplugged.just in case.

[@MrGuru666999]

With this you can make a cheap wireless hidden cam detector. Google Echo is transmitting in Wifi and Bluetooth That vertical light effect on the camera of the diode on your router was very weird

[@spookedjunglist]

High frequency rf doesn't penetrate as much as low frequency. Mmwave rf doesn't penetrate tinted windows, or leaves. To make it understandable for people who can't think logically. Here is an example. What do you notice when a car with a large sound system drives by your house? The loud treble? Or the bass?

[@GrantsPassTVRepair]

Thanks for the Interesting analogy.

[@hiddenrambo328]

Think of every device as a flame sure when you only examine and consider one or two flames you will note that the heat from these flames is small and safe now consider all devices in the neighbourhood the heat from the combined flames is larger and no longer as safe keep adding more people and more devices and you will reach a point where it is no longer safe.

[@GrantsPassTVRepair]

This microwave experiment I did may shed some new light on this topic for you. kzbin.info/www/bejne/sGWZfGxqZq-sqtU

[@stargazer7644]

Sure, if all those people are within a few inches of you. Learn about the inverse square law.

[@BjornV78]

The 1SS86 Sounds familiar :-) The 2.4Ghz and 5.3Ghz detectors combined in a keychain or so, makes it a very simple broadcoast detector for the 2 most used frequencies in residential WiFi routers.

[@GrantsPassTVRepair]

Thank you for recommending this diode.

[@BjornV78]

@@GrantsPassTVRepair no problem. Glad that i could help with this tip. I'm also wondering, if the "power" that received with this method, can be harvest and to boost up to a higher voltage, like a Joule thief circuit does.

[@GrantsPassTVRepair]

@@BjornV78 The power going to the LED is so small it's not likely to be of much use.

[@BjornV78]

@@GrantsPassTVRepair The detector that i build had 4 diodes, i think by adding more diodes then 1, the current gets higher by each diode.

[@GrantsPassTVRepair]

@@BjornV78 I but the 4 diode bridge thinking it would gather more power, but my LED didn't seem to get any brighter with this design.

[@Subgunman]

I have used a microwave mixer diode from an MPH X band radar gun as the detector diode to the Bird wattmeter. Oh yeah makes an excellent detector for the field strength meter. Not much difference between the Bird $130 field strength slug. Back in the day we used a four foot T8 fluorescent lamp a an indicator to see if w had a failure of the RF PA in the VHF handi talkies. We knew when it should start lighting based on the distance to the tube from the radio. A perfect PA at six watts would really light the tube to 3/4 brightness at six inches radio to tube. This process did not work too well on UHF frequencies however we never tried it with a shorter tube which may have made the difference.

[@GrantsPassTVRepair]

I remember watching a guy light up a fluorescent tube using RF energy by placing it near his antenna.

[@dieselray9999]

I love when you make these kinds of videos. I'm always looking for new ideas.

[@GrantsPassTVRepair]

That makes Two of us.

[@gregjohnson5194]

Nice fun video, I tried this with China 1ss866 diodes without H it didn’t work you did not say if your led was special or not but eBay has the H branded diodes 5 for $20. Little to expensive for a five minute experiment I think.

[@GrantsPassTVRepair]

Yes the price for the original Hitachi diode was a little disappointing. The 1N5711 also worked, but it's not as sensitive at the higher frequencies.

[@hubercats]

Great demo!

[@GrantsPassTVRepair]

Thanks!

[@DanielBerzinskas]

Here is some information about the last one: 146.52, which is the longest antenna of the LED+Diode detector, is used as the USA simplex calling frequency. Usually, after getting contact, you would move to a different frequency, say 146.505/146.500 (depending on the area) to do a longer conversation. 73, Daniel Berzinskas KQ4GOB

[@GrantsPassTVRepair]

Thanks. I'm a licensed ham operator myself, so I stuck with the 146.520 simplex frequency on my HT to avoid triggering any repeaters for my experiment. 73s.

[@buckstarchaser2376]

I'd like to hear the down-converted audio from an ultrasonic transducer when you're using that eavesdropping device, and when you're getting the occasional 9xxMHz blip. I'll bet your phone is chatting with it one way or another, as TVs are known to chat with phones via Ultrasonic. It's an area where regulations have somehow not been imagined, and yet ultrasonic and accelerometer data is being harvested in bulk while the getting is good. It's also weird how it became hard of hearing and confused when you were talking about its technical aspects and it was right in front of you.

[@stargazer7644]

Wherever you're getting your drugs from, you need to find a higher quality source.

[@georgeabraham7256]

There is a potential for improving a non-grounded faraday shield... to sync energy into noninterfering light. so your sensitive stuff lives inside an antenna that robs everything coming in. Patent Pending. ;)

[@kaboooom2000uk]

Really interesting stuff, inspiring me to make some and try them out :)

[@pdrg]

If it's just shy of 30mm each side for 2.4 GHz, that might be close to la generous ead length... So you could just connect the diode in antiparallel, splay, and trim to length.

[@jamesagoodall]

It would be interesting to see a spark gap emitter near these detectors. In particular, I have noticed that a stun gun generates a ton of RF energy, that can be damaging to cell phone cameras.

[@GrantsPassTVRepair]

I just tried using my stun gun next to these LED Detectors and they didn't light up, but it would be interesting to have a variable frequency spark gap and see what happens,

[@jamesagoodall]

@@GrantsPassTVRepair be careful taking video of a stun gun, my last cell phone camera was permanently damaged doing that.

[@Zerububble]

The google device may be transmitting on 915 /928 MHz for home automation use (Smart relays, light bulbs etc.) Perhaps Zwave or LoRA?

[@Sergio-ta3krt]

Thanks for the video! 73 de TA1AFS

[@jeanvaljohn3921]

Very awesome vid, And I know zero as bout rf signals, Fascinating information

[@rayislooking2]

Great video very interesting !

[@kreynolds1123]

Regarding microwave leaking. Supose you have a mains power and a transformer, very little power "leaks" untill you connect a load. By placing an antenna wire near a microwave conducting surface, currents in the surface induce currents in the wire, "Transformer" Normally a simple wire wouldn't disipate much energy and would simply reflect it back to the source, reactive power, but you put a load on the transformer and caused energy to leak into the LED instead.

[@GrantsPassTVRepair]

I can't understand what you are saying.

[@kreynolds1123]

@@GrantsPassTVRepair I'm saying by placing the anti parallel diode and LED next to the microwave, you are magnetically inducting energy into it. the microwave are inducing currents in the body of the microwave oven which normally would reflect microwaves off the walls of the microwave oven. But, when you bring the anti parallel Diode and Led antenna close it capacitivivly and inductivly couples energy from inside to outside. My first comment mentioned it was like a transformer connected to mains power line leaks very little energy. With no load on the secondary, Energy simply gets stored in the magnetic field and later released when the the current changes direction. There is a 90 degree phase seperation between voltage and current, so power is reflected back to the source rather consumed. But if you bring a secondary coil next to the primary coil and you have a load connected to tge secondary, power is inductivly coupled from the primary to tge secondary. The load pulls energy from one side of a transformer to the other. The diode LED circuit is pulling energy out. Maybe a more complete picture might be seen in looking at the phenomena as a transmission line with both capacitive and inductive coupling from one wire to another. Either way, the amount of energy coupled from one system to the other drops off faster than radiation's 1/ (distance squared).

[@GrantsPassTVRepair]

@@kreynolds1123 Sorry but I have never heard of an anti parallel diode, and I still can't understand what you're saying.

[@kreynolds1123]

@@GrantsPassTVRepair channel veritasium did a video "how electricity actually works". It's a dive into a different problem but some of what's covered is directly related to how energy is "leaking"

[@kreynolds1123]

@@GrantsPassTVRepair clearly a LED is just a special diode designed to emit visible light as electrons cross the NP junction loose energy and fall into (fill) holes. All diodes do this. Parallel here is simply refering to the physical alignment which is important because of the alignment with the electric and magnetic fields. Parallel diodes are diodes lined up with their respective NP junctions in the same physical direction. Both diodes will conduct in the same direction. But, Anti parallel diodes are lined up in physically in parallel, but each's NP junction order is the reverse of the other. Where current flows in one direction in one, the other diode conducts in the other direction.

[@aduedc]

Get a TinySA. It would also demodulate the signal, so you can hear and see the modulating signal

[@GrantsPassTVRepair]

I've tried this. It's impressively sensitive.

[@usaaudit738]

Try this. You can hear your tv remote on an unoccupied area on a portable AM radio band. Push a botton on your remote and move it around close to the radio. You should hear a tat tat noise.

[@herzogsbuick]

re: google home and 900mhz band: that might be just from a signal bus or something inside. there's this guy on youtube who takes ESP8266's, and just using software, he can transmit analog NTSC to a nearby tv, for instance.

[@erikas6874]

This project could be great to build on a designated PCB, with all tracks included.

[@krisraps]

yeah, That Would Be SUPERCOOL DIY Kit, Right?

[@mikeberger1688]

So that diode obviously looks like a better choice than 1n4148 you see in a lot of circuits. And you show a walkie talkie (HF) up to VHF, so I'm guessing it would be a nice basic FSM for HF and VHF amateur use? Thanks for nice video.

[@stargazer7644]

That diode is a UHF diode. A 1n4148 would work for HF and low VHF.

[@jagmarc]

I did this 50 years ago up to one gig back then were germanium diodes instead

[@GrantsPassTVRepair]

Did we have LED lights 50 years ago?

[@jagmarc]

@@GrantsPassTVRepair YES! The Texas TIL209 and a Mullard one CQ something.

[@jagmarc]

@@GrantsPassTVRepair and I also used more a moving coil meter with a pair of diodes attached, with a little pig-wire sticking out, broadband field strength as a utility for tuning up things

[@jagmarc]

@@GrantsPassTVRepair if you google "Semiconductor Circuit Design Texas Instruments" there is a book they printed in 1973, which mentions TIL209 many times. As a kid, Texas were near me in Bedford, UK

[@jagmarc]

@@GrantsPassTVRepair and mentioned in the book all those years ago was running the LED at 10 mA was fine, but running it at 20 mA no perceptible brightness increase. While still today newbies still run LEDs at 20.00 mA because that's what it says on the datasheet!

[@helichuck1]

I can tell you this!! I had to get rid of my magnetic Loop antenna . I was using it at my daughters house and as soon as I started to transmit my heart went crazy with PVC's. And it happened at a field exercise with our club, when I was about 10 feet under a dipole on 40 meters with 100watts. So you do have to be careful.

[@GrantsPassTVRepair]

Unless you have a pace maker I'm a bit of a skeptic when people tell me stories like yours.

[@stargazer7644]

@@GrantsPassTVRepair He probably died driving past a 50,000 watt AM radio station.

[@morpher44]

good video. You did't mention Avramenko plug, however.

[@newtonm914]

impressive!

[@seyedmarashi1122]

it seems you get frequency law well, all of this light is from stations. most of the guys think cosmic rays will turn light now

[@ahmetozdemir7173]

Thanks for video. Why have we need use 1SS86 diode? There are also rf diodes which have lower than the leakage current ratio of this diode. Is this criterion important to you? Which criteria should we consider when choosing between RF diodes for this circuit? Thank you.

[@GrantsPassTVRepair]

I haven't researched these diodes in deph, but it's the best one I'm aware of for what I'm doing.

[@justtinkering6713]

Why won't a 1N34a work?

[@stargazer7644]

@@justtinkering6713 The 1SS86 is a UHF diode. The 1N34A isn't even rated to 40 MHz. It simply won't switch efficiently at these UHF and microwave frequencies.

[@georgeabraham7256]

Thank you sir...

[@marivargas6389]

Thanks! , gretings from Chile

[@karlswanson95]

Can you change orientation of antenna to determine the signal path?

[@stargazer7644]

Yes, a dipole antenna receives best broadside to the signal. If you point a wire end toward the source it'll be weaker. Note there's a 180 degree ambiguity. Also note that you'll also lose signal if you're cross polarized, but that won't help you find the source.

[@Sean_y4k2l5]

this is really cool, thank you!

[@lukesmither1004]

6:35 watch how the detector on the google home goes mad when he mentioned harmful radiation

[@MrPlastkort]

My old nokia phone had an antenna that blinked when there was an impending call or message incomming ;)

[@gregoriocinco921]

Same principle as demonstrated.

[@marcopilati7464]

Genius!!! Thanks!

[@Enternal_beings]

Awesome

[@suzesiviter6083]

The more interesting frequency would be the 24ghz the upgraded 5g towers use. I disagree just because its non ionizing its safe, we dont know how they effect the mm scales in the brain, it will make them resonate, but to what degree no one knows yet as money always comes before safety.

[@GrantsPassTVRepair]

What about light itself. It's also on the electromagnetic spectrum and it's a far higher frequency than 5 G.

[@suzesiviter6083]

@@GrantsPassTVRepair Light which is composed of photons are produced when a electron falls from an higher energy level(outer orbits) to a lower energy level(lower orbit) in the atoms, the difference in distance between the orbits determines the wavelength, so these high frequencies are only exciting frequencies at the atomic scale. 5g 25ghz however is resonating parts in our bodies and minds in the mm scale, of which there are many parts influenced by this resonance, just like a wine glass excited to its resonant frequency breaking, repetitive resonance of any part can lead to its deteriation or even destruction, now Nokia and the others will tell us its perfectly safe, but of course they would do that with big money involved, but the truth is, they simply do not know and are willing to risk injury, as such things as cancer, brain defects etc over a long period of time is very difficult to prove in court.

[@suzesiviter6083]

@@GrantsPassTVRepair There is a true story of a engineering being accidently locked into a VHF amplifier room at Emerley tower TV mast, the radio frequencies literally fried him. So you cannot use only frequency as an argument for safety unless its colour wavelengths or above of course as per my previous answer (notable exception of radiation as we know). So, safety is really down to power levels, distance, dispersion patterns and the parts of the body those frequencies will excite and possibly cause damage to.

[@GrantsPassTVRepair]

@@suzesiviter6083 Yea being to close to strong radio waves can be deadly. You might like this experiment I did. kzbin.info/www/bejne/f3Tblnl6hbh-ick

[@suzesiviter6083]

@@GrantsPassTVRepair Watching it, one point, I think you are assuming only the heating effect of RF can cause damage, but any frequency that hits the right resonance of some organic material may also destroy it. You remember the old Tesla experiment where he built a vibration machine that shook the foundations of a building 1/4 mile away and the police had to break his door down? well that shows little energy is required if you manage to get the resonant frequency right.

[@anthony9344]

Could you amplify the sensitivity or run multiple together and increase

[@GrantsPassTVRepair]

I don't know how to amplify this, but a well tuned antenna is necessary for this to work well.

[@tiville421]

also called lectennas :) thanks for sharing!

[@ForceOfChaos1776]

Hey thanks. mm reference? Also is the 3rd RF milli?

[@stevenfletcher9851]

Outstanding Demonstration. But How do I design each element to respond to a different frequency? Is there a way to specifically tune or set each LED diode to respond to a specific frequency of my choice? even one that i may stumble upon by accident? in the future?

[@GrantsPassTVRepair]

Yes the element length determines what frequency they respond to. If you look up dipole calculator on google you will find calculators that do the math for you.

[@savagejabbit5929]

How does something like the acousticom rf meter work from 200MHz to 8GHz 📡🤔

[@DZI10]

I'm new to this but how does it work with that meter? Can I potentially use the clamp on my voltmeter to see the same results?

[@GrantsPassTVRepair]

Voltmeters do not have clamp on options. Some multimeters do, but they are for measuring current rather than voltage, and their current scale would not be sensitive enough to detect any current from radio frequencies.

[@DZI10]

@@GrantsPassTVRepair ah that makes sense thanks for the help

[@linkavichtruousky1]

Excellent video thank you

[@RynaxAlien]

Just diode and LED is powered by EM waves? How to make it more sensitive and can it be made to pick up 5G?

[@Kangsteri]

Thanks!

[@gcmd5852]

Could one of the automotive remote transmitter testers be modified with a stronger antenna to sniff out RF devices? ( or could you recommend an RF “ sniffer” ) With all the electronic gadgets available nowadays we’re seeing interference issues in the automotive repair industry. Great channel

[@stargazer7644]

Use a spectrum analyzer like a TinySA.

[@nextnext8902]

Thank you. Hello how i can calculate antenna lenght? Which is the good site for calculate and learn? And should the antenna be straight? Would it be different if it wasn't straight?

[@GrantsPassTVRepair]

Yes ideally the antennas shoud be straight, but you can get away with a little bending. There are many dipole antenna calculators online. Here is one. www.westmountainradio.com/antenna_calculator.php

[@aaronmanning2114]

What the hell are to blue lines when you show the led by the router?

[@GrantsPassTVRepair]

I never noticed the blue lines before you mentioned it, but I'm not sure what's causing this.

[@StreakyP]

Question... was the microwave oven actually leaking or was your probe just inside the non-propagating evanescent field region "outside the box"?.... I remember in School physics doing the 10GHz total internal reflection experiment through a wax prism & even though "nothing radiated out the side" you could still get some interesting effects if another prism was brought close to the "dark side".

[@GrantsPassTVRepair]

My LED was detecting the leakage coming through the window of the microwave oven, but I don't believe it had anything to do with the microwave being defective in any way..

[@TimFoo6143]

Several other diodes can be use, the trick is to get one with CJ to be as low as possible. An thanks to the Measurement capabilities of the recently availble transistors testers, this component parameter can be measured. It is likely that the overall CJ can be reduced by connecting several diodes in series, however that will likely to create a loop antenna (and there are example of these type of LEctennas on youtube eg Rectangular loop REctanna with 5 signal diodes (probably 1N4148) in series on the pheriphery (the outer limits or edge of rectangular loop). kzbin.info/www/bejne/iH6mZZSZfL6YiJo Series of 6 Signal Diodes in the center ring to act as Detector with Star-Dipole "antenna" kzbin.info/www/bejne/mHjIe31mpZh_l5o ) rather than the classical dipole.

[@GrantsPassTVRepair]

I tried the 1N4148 and it did work on the lower frequencies, but not on my wifi router.

[@Danish_Dan07]

How long is the antenna needed for a frequency of 27mhz?

[@GrantsPassTVRepair]

8.667 feet for each element.

[@krisraps]

This Is SUCH A Cool project, Did It Today Myself, Now I Just Need To Find Out How To Fien Tune It For My Needs Do Any Of You Know, Is There Anyone Who Made A DIY version With Just Changing Frequencies On it To See If There's Like 170.000 Mhz Broadcasting Happening In Air Right Now And Tune It To Any Frequencie? Well, That Would Be The Coolest Thing Ever, But I Guess The "Tune" Would Be Some Sort of Antenna Changing Thing Because It Catches The Broadcast Transmission By Capturing The Signal Itself And Turning it Back Into Electricity So the Antenna Must Be In A Correct Lenght Or It Would Not Work.

[@OverUnity7734]

Sounds like a couple small telescoping antennas would work well for that .

[@galinstan5603]

@@OverUnity7734 I had the exact same thought, just before I clicked on your reply !

[@jackevans2386]

Hi Grant, 1SS86 is hard to get here. Is there an easy way to choose an alternative by data sheet specs ? ie. which specs signify which diode may be appropriate ? is it Vf or capacitance etc ?

[@GrantsPassTVRepair]

I bought a few of them on ebay, but they didn't come with any specs. Where do you live that they are so difficult to find?

[@jackevans2386]

@@GrantsPassTVRepair I'm in New Zealand which is almost on top of the world or bottom of the world, depending on your orientation in space. There's a lot of fake diodes floating around Ebay and AliExpress so hoped to buy from a reputable dealer.

[@GrantsPassTVRepair]

@@jackevans2386Greetings from Grants Pass Oregon USA. I bought some of the diodes mentioned in this video on ebay which worked fine.

[@davidmartin1628]

The device is formally known as "rectenna". Hope this helps for those looking to understand the principals on how this device works!

[@JA-yy6bd]

David Martin could you use this setup to detect car tracker ?

[@gamerartistnarvel6615]

If you wanted to augment it's field of detection, let's say one meter, what would you do?

[@GrantsPassTVRepair]

I made a parabolic dish for my diode LED combo, and attached the output to a small audio amplifier, and I was able to hear signals many meters away from my antenna.

[@Jeffindsm]

You’re above googles head..😆 Sorry I don’t understand 😆

[@Pyromancers]

Are these a particular brand? I've been kinda hit and miss with all the recommended lectenna diodes. Trying to find something that performs well, but is easy for people to obtain. Need quite a few to use with my science students. I've got the NTE112 right now and it seems to work ok, but I think yours might be more sensitive. Did manage to find a microamp ammeter which makes this way cooler so thanks for that tip! Unlike your video, the top video on youtube for lectenna by the Navy tells you to wire this the wrong way so I'm glad I found yours or I would have been pissed for hours.

[@GrantsPassTVRepair]

I don't know any more than what I showed in this video, but I found the ones I used on ebay, and have not had any probelms with them on a multiple of different frequencies from the AM broadcast band on up to microwave frequencies.

[@stargazer7644]

Use UHF schottky diodes. Or microwave schottky diodes, depending on how high up in frequency you want to go.

[@lowqualityantenna]

Would you present this to the ham radio club?

[@GrantsPassTVRepair]

For sure.

[@GrantsPassTVRepair]

When is the next meeting?

[@TechTed1]

Amazing

[@johnchhu3914]

Hi Grant, I see the diagram of the diode and led together but how is the antenna wire connected exactly? A photo or diagram would be much helpful but a description would be good. Say for the 2.4ghz antenna. It;s 29.7, are those two separate cuts of 29.7 for each side or one cut of 59.4mm? and then how or where is connected to? Thanks

[@GrantsPassTVRepair]

You place the diode and the LED right next to each other as shown in my drawing.

[@johnchhu3914]

@@GrantsPassTVRepair Yes that part is clear, but where does the antenna connect to? - Wait are the leads of the diode used as the antenna?

[@GrantsPassTVRepair]

The wires on each side of diodes are the antennas for the frequencies I mentioned, but when conducting this experiment with my long wire antenna I ground one side and put my antenna on the other side.

[@hubercats]

Thanks for sharing this video. Did you install any capacitors in the antenna detectors to create an LC resonant detector for each? Or does each antenna consist of only three parts: Schottky diode, LED and pieces of wire cut to the correct lengths?

[@GrantsPassTVRepair]

The closest I came to doing that was this crystal radio kzbin.info/www/bejne/laHQY6eCg5t-hbM

[@morpher44]

8:12 looks like your math is for quarter-wave and not halfwave. TRUE? Speed of light in copper?

[@stargazer7644]

Each wire should be about 1/4 wavelength long to make a 1/2 wave dipole. Shorter will be less efficient.

[@ahmetozdemir7173]

I guess LED has no function in detecting em. Can the LED be placed at a greater distance from the diode? have you tried

[@GrantsPassTVRepair]

I'm not sue, but I may try it and find out.

[@fpsFAMOUS]

Any readers that measure 5G towers?

[@mohamednevim1124]

Thank you so much for your neat ideas, (Sub and one Up)! Is it possible to add an amplifier ?

[@GrantsPassTVRepair]

Yes you can add an amplifier. I did so and was able to hear my wifi modem from many feet away.

[@mohamednevim1124]

@@GrantsPassTVRepair great. Can you guide me to a simple amplifier video or any source. Thanks

[@nextnext8902]

Hello. Which is better for dipole antenna? (λ /4 for each arm or λ /2 for each arm, or in between)

[@GrantsPassTVRepair]

Mine seemed to work best using one quarter wave length for each arm.

[@stargazer7644]

1/2 wave total (1/4 wave for each arm) is resonant. That's what you're looking for.

[@TechniCraftYT]

I have a sb 320 schottky diode does it work with this

[@GrantsPassTVRepair]

I don't know anything about the diode you mentioned, but I've tried a variety of diodes, and the one with the H printed on the diode made by Hitachi under the part number 2SS86 is the only one I've found so far that works at the higher frequencies such as cell phones, microwaves and wifi modems. Others only work at the lower frequencies such as with AM broadcast stations.

[@TechniCraftYT]

​@@GrantsPassTVRepairi buyed an 1n4148 and it works with my wifi repeater.

[@ahmetmutlu348]

I guess its about diodes supported frequency and reverse voltage loss and forward voltage loss... if the loss is small enough it mostlikely will word... just a gues... as rf is wibrating/switcging power so fast and in small woltages that cheap diodes are leaking pig part of power in reverse causing partial shoer and in forvard signal pulse losing too much power while trying to saturate ... so on lower frequencies and higher power signals cheaper diodes will thworethically work better... 😊

[@itriedtotellyou9740]

can you explain more about the resonant antennae?

[@GrantsPassTVRepair]

You can look up Standing Wave Ratio on youtube and find more detailed info. Here's an example. kzbin.info/www/bejne/rWLIdmRpir10gdU

[@stargazer7644]

@@GrantsPassTVRepair SWR is not antenna resonance. When an antenna is resonant with an incoming RF wave, the voltage in the antenna builds up to a much higher level. That voltage is used to light the LED. It's like pushing someone on a swing. If you push at the right time on each cycle, the swing will go higher and higher.

[@robertperun4634]

HI..Q:how precize shoul be the antena/wire lenght ?, i have tried to test microwave oven with 29 +-1mm but i am not able to detect anything with this setup ,

[@GrantsPassTVRepair]

I would think 29.1 should be close enough to work. Did you use the same diode I mentioned and follow the correct polarity?

[@robertperun4634]

@@GrantsPassTVRepair yes diode is the same , but the lenght is something between 29-30mm (+-1mm) cutted by hand :)

[@GrantsPassTVRepair]

@@robertperun4634 I think that shoud be close enough to work. I'm also able to light mine up with my wifi router and my cell phone when I find the right spot to place my LED.

[@stargazer7644]

You have to be using a diode that will function at microwave frequencies

[@KavorkaDesigns]

One's talking to WiFi at 2.4GHz the other is talking to the phones GSM 900MHz

[@Alan-bn6ii]

by any chance can you do one for 27mhz pls so i can make one to fit the top of my antenna

[@GrantsPassTVRepair]

If I made one for channel 20 which is in the middle of the CB band at 27.205 Mhz each element of the antenna should be about 103.2 inches long, but i'm not sure how you could make the LED light up by placing it on top of your CB antenna.

[@stargazer7644]

Just put a neon bulb on the tip of the antenna with one leg sticking up in the air.

[@Muck-qy2oo]

How does your setup work with these dipoles being so close to each other?

[@GrantsPassTVRepair]

I don't know, but as you saw it does work.

[@Muck-qy2oo]

@@GrantsPassTVRepair You may make an experiment some time what happens if you space them all just 3 mm apart. :)

[@GrantsPassTVRepair]

@@Muck-qy2oo Interesting thought, although I'm not sure you would see much difference with the setup I have since they are receive antennas. When it comes to transmitting that's another story. I have a dipole antenna in a tree, and allowing my antenna to be to close to the tree branches greatly reduces on the power output from my antenna.

[@stargazer7644]

The dipoles are resonant on different bands. They won't interact much.

[@johangoethe2472]

Dave, what is thickness (diameter) or number of the copper wire in each case ?

[@GrantsPassTVRepair]

The thickness of the wire is probably not that critical, I'd guess you could use 20 to 30 gauge wire and it would work fine. The lengths for different frequencies were mentioned in the video.

[@johangoethe2472]

@@GrantsPassTVRepair Thank you very much for your quick answer !!!!!!

[@danthemann6565]

I do think the thickness makes a difference. Having used a watt meter to measure VSWR, I found that antenna shape plays a lesser role at determining resonant frequency as does the mass/amount of antenna material.

[@aaronsantana7077]

¿Can it be used with other kind of diodes, like 1N4148?

[@GrantsPassTVRepair]

I'm sure there are other diodes that may work, but of the various diodes I've tried the one I suggest in this video was the best. I tried some of the diodes people suggest for crystal radios and they worked to a lesser degree, but not well on the higher frequency radio waves.

[@stargazer7644]

You have to use a diode that switches at least as fast as the frequency you're trying to pick up. A 1n4148 isn't going to work very well above 100 MHz or so. Also, silicon diodes need higher signal levels. Schottky or germanium diodes would be better. The 1SS86 is a UHF Schottky diode. Much better for the job. You're looking for an RF diode.

[@maxwarfield6699]

Complete NOOB here. What is it, that is capturing the RF waves? Is it the diode's leads or the LED's leads, or both? Also, what if you soldered a metal [or fine mesh] dish to this set-up [to look and act sort of, like a tiny radar] would it pick-up RF signals from further away, would it help in any way? Let me know - I'm trying to learn. Thank you kindly

[@GrantsPassTVRepair]

To answer your first question the diode leads are in parallel with the LEDs and the antenna wire. To me that means it's the wire picking up the waves. As far as concentrating the energy in a parabolic reflector goes it sounds like it should help. Good idea for an experiment.

[@maxwarfield6699]

Thanks for replying, I really appreciate it. One more question: you use a micro-amp meter in this video, to measure RF? What measuring unit, would that be, what would it be called? Please let me know. Anyhoo, great video, as per usual, and thank you for the encouraging words, regarding my "radar" idea. Be safe. Cheers!

[@GrantsPassTVRepair]

@@maxwarfield6699 My micro-amp meter can meausre a few millionths of an amp. It can't measure the RF energy directly, but it can measure it after it gets rectified through the diode and becomes DC. .

[@maxwarfield6699]

Thanks for replying, really. Ok, "mind BLOWN" you can rectify an RF signal?! I'm no expert, at all, but isn't an RF signal, an electro-magnetic wave? Thus massless [photons], that's quite different from electrons [which have mass] how can one rectify something which has no mass, with a simple diode? Here's a terrible example: The ocean has waves, but can you rectify them with a diode? They are two VERY different things. Please correct me if I'm wrong. "Mind still BLOWN"

[@ahmetozdemir7173]

@@maxwarfield6699 it is possible with diode.

[@modmutt]

Pretty sure you need a new microwave

[@davidalan1040]

Is this sensitive enough to detect the RF signals that gang stalkers use to hurt/harm targeted individuals?

[@stargazer7644]

Say what?

[@ahmetmutlu348]

Depends on frequency their device uses... and how far they are 😊

[@diligentescape8137]

Even though we are bombarded with non lethal non ionizing radiation doesn’t mean that the frequencies won’t affect your mood, behavior, or even manifest physical ailments. Thanks for the video i found it very helpful

[@stargazer7644]

Actually, it does.

[@josejoelambil7842]

Sir..what diode that we use for detecting the frequency of gold?..

[@GrantsPassTVRepair]

If I knew I'd be a billionaire.

[@josejoelambil7842]

@@GrantsPassTVRepair ..ha ha ha ..you're right men..it's only an idea.

[@johangoethe2472]

@@GrantsPassTVRepair Ha ha ha ha ha

[@markusepple6204]

Nice, but for a single calculation of division You don't need a whole mobile phone app

[@GrantsPassTVRepair]

Dividing the desired Frequency into 468 give you length in feet, but it got a little tricky trying to convert tenths and hundredths of an inch into millimeters. .

[@robertcalkjr.8325]

I could only find a datasheet for a 1SS86.

[@GrantsPassTVRepair]

I couldn't find much on it either, but I did find them available through eBay.

[@robertcalkjr.8325]

They probably thought that the "1" was an "I".