Now build a additional spectrum analyzer for 10 bucks and every one is happy ;-)
@redsquirrelftw5 жыл бұрын
Would a SDR make a decent spectrum analyzer? I guess most have a more limited range though.
@JohnDoe-hm8lr5 жыл бұрын
It would definitely work, although you'd have to be careful about the input signal level as they saturate easily, it also takes a good amount of time to sweep a large bandwidth.
@soothcoder5 жыл бұрын
Yes a HackRF would have more than enough frequency range although slow sweep (but then do we care?). They are a bit 'deaf' though. Can't hurt to try though can it?
@PlaceholderforBjorn5 жыл бұрын
Test it with RTLSDR for 10$
@amaldev0005 жыл бұрын
Dave should probably do a video with $165 handheld spectrum Analysers from rfexplorer.com
@tablatronix5 жыл бұрын
One of the best videos in a while!
@RicoElectrico5 жыл бұрын
@qashqai q Spot on. I'd rather have Dave post rarer, but higher effort content. I don't watch the mailbags anymore, they seem to become a chore for him. Teardowns are a hit or miss really. Dave sometimes does too little research. Though that correlates with "off-the-cuff" slogan.
@EEVblog5 жыл бұрын
RicoElectrico Correct, I do practically zero research, that's the way I've always done videos and have built my channel from nothing doing that.
@urdnal5 жыл бұрын
@@EEVblog How about more DIY expensive tools that work as well as the professional ones. Stickin' it to the man. How about an active oscilloscope probe next? Or a DIY Hewlett Packard 547a current tracer? I could probably use one but not enough to justify $200 on ebay
@midnightman0115 жыл бұрын
Totally agree .. high quality content .. stick it to the fat cats Dave .. maybe build a differential probe next from Ebay parts .. there are a ton of broke engineers and hobbyists out there
@jafinch785 жыл бұрын
Yes sir. An RF probe came to mind from an old set of computer external speakers... that'd be about as cost effective. SDR ideas don't seem bad for cheap spectrum analyzers especially if there is an oscilloscope plugin... though I've figured a set of attenuators for the range and profiling the SDR well to know its range of performance to characterize the limitations so you don't blow it up. Probably a current limiting input thingamajiggy too. Normalizer dohicky would be impressive. Least that's what comes to mind. I was also wondering about making a leveling head for the cheapo signal generators since they're so cost effective. Trips me out how cheap some of the modules are and how like this detailed video demonstrates using the hardline or rigid or I guess it's called semi-rigid cable... can be used to make decent kit alone basically or with a or some modules. So much, I just ordered a range of modules, plus some, to make an Antenna Analyzer or looks like is going to be a VNA using Erik's latest modularized version he notes on the SoftwareControlledHamRadio groups.io post on Analyzer Comparison since seems impressive: github.com/erikkaashoek/Tapr-VNA
@patryksikora52625 жыл бұрын
I'm looking forward to next video "Build a $100 DIY Spectrum Analyzer"
@TheBananaPlug5 жыл бұрын
It might not be $10, but the W7ZOI homebrew SA was a good design/project from the '90's, rebooted here: hfsignals.blogspot.com/p/specan-reboot-of-w7zoi.html
@pa4tim5 жыл бұрын
I have done that (500 MHz) , is a lot of work, by the time it was finished I had a few real SA's. www.pa4tim.nl/?p=1643 , it is a while back so the page is in Dutch, newer projects etc are in English.
@PixelSchnitzel5 жыл бұрын
I came here to say this is one of your best videos in a while and am amazed to see how many others are saying the same thing. I couldn't believe you peeled back that Tekbox cover; thanks for doing that!
@RemcoStoutjesdijk5 жыл бұрын
You had time to build it to scale and to paint it!!!
@EEVblog5 жыл бұрын
Only two coats!
@altersami96605 жыл бұрын
@@EEVblog I believe this would do a better job coating it than the spray-can version: www.amazon.com/Performix-11602-6-075815116024-Plasti-Dip/dp/B000ZN1T16/ref=sr_1_9?keywords=plastidip&qid=1549645102&sr=8-9
@DavidLindes3 жыл бұрын
@@altersami9660 yeah... I saw the name Plasti-DIP ... and a spray can, and I was like... what? Plasti-Dip is supposed to be a thing you *_DIP_* into, not spray on.... silly people, giving them a market for this.... (I mean, I suppose there are probably use cases where dipping is impossible and the spray is useful. But for this use case? Dipping seems entirely appropriate. Ah well.)
@erikgleber66525 жыл бұрын
Another solution for your rubber coating: buy ABS filament for 3d printers and solve it in acetone. Then you can use a brush to apply it. The acetone vaporizes on its own at >20°C and only the ABS is left
@TheMeddlingKidsHaunt5 жыл бұрын
It's funny that I don't have any use for the probe but found it so entertaining.
@acetyra5 жыл бұрын
Need more of these typ of videos
@Rob25 жыл бұрын
Welcome to the world of radio frequency hobbyists / radio amateurs! We knew this all the time. I made such a probe years ago and used it many times, it is also useful to tap off some signal from an oscillator coil to measure the frequency using a counter, to tune a transmitter amplifier while constructing/experimenting, etc etc.
@EEVblog5 жыл бұрын
Yes, they are quite common.
@KidCe.5 жыл бұрын
Is it also usefull for making measurements in Audio circuits? I'm thinking off finding noise sources in the 1khz to 40khz range. Afaik RF is much higher then what interferes with audio ...
@Rob25 жыл бұрын
For that I have a different probe that has a coil with some more turns at the end. Just a length of RG58 with a BNC at one end (for the scope) and a coil made from .5mm enamelled wire that I threaded through a length of insulation tube (4-5cm), ends pulled together so it forms a small loop. Finished with some heatshrink to cover the solder joint to the end of the cable. Experiment with the number of turns depending on the signal pickup level you need and the high-frequency response. For this region it should not be a problem to have like 20-40 turns, but of course it will no longer work so well in the MHz range.
@mauriceharvey44765 жыл бұрын
We knew this all the time, I made one years ago. Well why didn’t you take the time and effort and put it up on KZbin and not wait for other people. With your sort of attitude no wonder the young people are not coming into amateur electronics. Why are your sort so protective of knowledge?
@ligius35 жыл бұрын
@@KidCe. Just use a normal flat coil for that and either a cheap oscilloscope or a cheap audio amplifier. Or search for "superprobe".
@Choober652 жыл бұрын
That faint thudding at the end of the video is Tekbox executives jumping out of the windows.
5 жыл бұрын
Great, now I just need a Spectrum analyzer :|
@EEVblog5 жыл бұрын
You scope likely has FFT
@scienteer35625 жыл бұрын
@@EEVblog or cheap RTL dongle or HackRf will work.
@EnjKat5 жыл бұрын
As SpecA’s go, you can likely get the Rigel jobbie that Dave was using for ~1500 $USD or less. That’s serious coin, but WAY cheaper than an equivalent unit a decade ago...
@TemporalRecall5 жыл бұрын
Yeah about $20 for the RTL SDR + Spektrum (free) www.rtl-sdr.com/poor-mans-spectrum-analyzer-with-an-rtl-sdr-and-noise-source/
@scienteer35625 жыл бұрын
@@samuelcomeau Install it with Pothosware. Dead easy.
@stevetobias48904 жыл бұрын
Not sure why you have a few thumbs down. A huge money saver that will give the same performance. This is great Dave. Thank you yet again
@conorstewart22149 ай бұрын
The thumbs down will be from the company that makes the probes or from people who bought the probes and now feel like they wasted their money.
@iceCOLDkillaxDLoL5 жыл бұрын
The guys at tekbox spent houndres of hours on r&d for this thing to work properly. Dave botches something together in 10 minutes and it works just as fine if not better than the pro kit. :D
@khronscave5 жыл бұрын
R&D, or D&M (design & marketing)? :P
@acrodrigues15 жыл бұрын
Research & Development
@SeanBZA5 жыл бұрын
Getting those curves that are individual, and that are a true reflection on the device, as opposed to lucky try and it worked. Plus the whole repeatable manufacture thing that means you can interchange probes, and not have to run a calibration on each new one you get, just use the curve supplied, which is well within a specified tolerance spread.
@jovangrbic972 жыл бұрын
For all those wondering the weird round package is a type 86 plastic package, and the amplifier, which has only GND, IN, OUT, is a MSA0486.
@commonmogoreanu71355 жыл бұрын
That's the kinds of videos we are here for. Thank you!
@Shabbymannen5 жыл бұрын
That piece of coax is beautiful.
@russoft5 жыл бұрын
I may actually join the discussion over on the forum. We have billions of these DIY H-field probes in our lab of varying qualities. Might be rather entertaining to post a picture of all of them.
@EEVblog5 жыл бұрын
Please do!
@streaky815 жыл бұрын
I got loads of those RF amps sitting around, they're handy because you can use a buck converter and set the output voltage to calibrate gain with them, no need to use an attenuator.
@kenchilton2 жыл бұрын
Use the PastiDip in the non-aerosol can or liquid electrical tape and you will be much happier. Also, you can make the very small loops from very small diameter coax. The coax does not need to be rigid, and if you put some steel wires or small fiberglass/carbon-fiber rods along side the coax for the small loop, it will add the needed rigidity. Use heat shrink over the coax and stiffener for the straight part and dip/paint on the liquid tape over the loop. The small loop can be even more finicky to cut and solder, so short the end of it back over the coax before bending it into the loop, then solder the whole end back to the shield to make the loop. To cut the gap in the middle, you only need to make a single slice, and when you dip it or brush on the tape, it will fill that slot and Robert is your mother’s brother.
@davidbrewer79375 жыл бұрын
We always made our own probes like this. You can make them more selectable by adjusting the size of the loop.
@notamouse56305 жыл бұрын
You don't need plasti-dip for probe coating, use electrical tape. It almost looks like the cheaper one could be prototyped in strip board if the need was urgent enough. For a cheap spectrum analyzer, attach a 10 MSPS SPI ADC to a raspberry pi, write some code to perform FFT on the data using the GPU and pipe the output to a graphing utility to get an approximation of a spectrum analyzer.
@1kreature5 жыл бұрын
You know you need to take this to the next level right? First you use a 3d printer as x/y scanning platform for the board (printer can be fed gcode for movements from pc via usb) and then record the data from the oscilloscope via for example python integration with scope (usb again). Recording the spectrum on each position in a grid and display everything in a nice overlay on a photo of the board. User could then either see a sum/max of all the emissions or scroll through the spectrum and visualize a frequency slice in the overlay. Now that's sexy!
@EEVblog5 жыл бұрын
Yes, I said that in the previous video.
@simonbaxter80015 жыл бұрын
There is a product out there that is an array of loops in a paper sheet size bed. Its multiplexed and scanned into an analyser. You can put an image of the pcb layout over the scan data to give you an RF 'heat' image. Think its made by Emscan.com from memory.
@1kreature5 жыл бұрын
@@simonbaxter8001 I know. I've used one. This is cheaper and more fun...
@JackZimmermann5 жыл бұрын
Well, that came in handy! Things ordered, now the waiting begins. Thanks a lot! Looking forward to the E-field probe.
@kapioskapiopoylos73385 жыл бұрын
love all your videos, but i have a preference on EMC/EMI things, keep it up
@Corgitronics5 жыл бұрын
Great video! This is the kind of content that I really like, this is definitely worth the patreon subscription.
@TymexComputing7 ай бұрын
Very instructive - thank you!
@hgbugalou5 жыл бұрын
That coax looks like they just dipped normal braided shielding and dipped it in some solder.
@Master_zzz5 жыл бұрын
That is exactly what they did.
@StreuB15 жыл бұрын
Thats how many places make semi-rigid in the smaller coax styles. Very common.
@NetworkXIII5 жыл бұрын
Great video as always, Dave. We’re dealing with an EMC issue on a project right now..
@williambello40895 жыл бұрын
I built an EMC probe for less than $8, using a toraial core coil and soic op amp. I needed to measure current WITHOUT physically touching the current-carrying conductor. Torrid core coil to the rescue! You can see it, and the printed circuit board CAD files that I offer as "open source", on my MeWe page @ Esp and IoT
@seanet13105 жыл бұрын
Good noise floor for the couple dollar pre-amp. I've seen worse from decent commercial jobs. You can also make a quick and dirty e-field probe by cutting away some shield leaving a very short stub of the solid core conductor then insulating against shorts. Even if you don't have a specan these tools are useful with an oscilloscope (you will need the preamp). If it has fft like most dso do then that is a bonus. Home made H-felds are great, beat the old emco kit any day of the week
@Bushougoma5 жыл бұрын
13:29 It looks like a tool handle dip to me 4:14 the surface finish is rough, bumpy, and full of holes. It's likely the same thing you used Plastidip and that shade of blue is one of the three shades they sell. It also comes in a can so you can dunk the part rather than spray it. Just just dunk the PCB into the container, pull it out, and let it drip dry. Repeat the process to thicken the coat.
@killymxi5 жыл бұрын
Bushougoma Looks like they also used some primer coating to make rough surface layer on PCB and make it stick.
@nraynaud5 жыл бұрын
I think you might be slightly wrong about the commercial probe coating. I feel like they did a grippy gritty transparent conformal coating to help adhesion of the blue shmoo.
@EEVblog5 жыл бұрын
Possibly
@585585MC5 жыл бұрын
Dave's videos are really fun to watch. Few other channels can do the same.
@rbmwiv5 жыл бұрын
Thanks again Dave. Way cheaper and super easy. You’re the man!!! Gonna build my own.
@dwanedibley6965 жыл бұрын
Brilliant dialogue, very entertaining and informative. Many thanks for sharing
@flemmingchristiansen24625 жыл бұрын
In my book, this is a proper tear down. Great work.
@Mustakari5 жыл бұрын
Excellent! Thank you Dave. Videos like this are why I subscribe to EEVblog.
@kissingfrogs5 жыл бұрын
Great Video. Top marks for peeling back the rubber.
@abstring5 жыл бұрын
Great video Dave! The blue coating on the outside of the TekBox probes is likely a low-pressure overmold, which is the same material used on strain reliefs for cables, etc.
@VincentFischer5 жыл бұрын
I love RG402. Nothing better for DIY antennas
@clau22725 жыл бұрын
we've always called that soldered braid stuff "semi-rigid" coax. Solid copper outer shield was called "rigid" ..
@EEVblog5 жыл бұрын
Yes, it's semi-rigid.
@NoahFect5 жыл бұрын
Actually the right term for this stuff is "handflex." Examples of semi-rigid coax would include the 0.086" and 0.141" cables with the solid tinned-copper shield that you see in commercial spectrum analyzers and other RF gear. It is not meant to be formed by hand and often breaks when you try.
@DanShepherd723 жыл бұрын
Nice video, one has to question why the commercial one’s are so expensive. It reminds me of when companies rub off chip numbers to hide how they are made. Probably also would reveal the company’s mark up vs actual part costs
@pawematuszczak73165 жыл бұрын
Great video! Waiting for Part 2 with a little EMI pre-testing howto!
@vincei42525 жыл бұрын
Dave, you need an x-ray machine. Just saying :-)
@EEVblog5 жыл бұрын
Not possible to buy one here without a license.
@vincei42525 жыл бұрын
@@EEVblog ugh. That sucks.
@zvpunry19715 жыл бұрын
I like the type of x-ray machine bigclive uses ;)
@vincei42525 жыл бұрын
@@zvpunry1971 Bigclive has an x-ray machine ?
@ahuad5 жыл бұрын
Hahaha I have a lot of different x-ray models at home and didn't know it.... Hilarious
@wombatillo5 жыл бұрын
You can make the H-field loop solder connection and shield cutting in many ways. There will be very little performance difference if you make it unsymmetric and just solder the center conductor to the shield on one side. Yeah, it won't be geometrically symmetric, but it will be electrically almost the same as the more complicated construction.
@schitlipz5 жыл бұрын
Thanks, Dave! Very good.
@parpid5 жыл бұрын
Frigging amazing hack! Everyone is going to build one. Thank you Dave, really
@arthurvin29375 жыл бұрын
Now start mass production and sell it on Ebay for $50 and bundle it with calibration certificate "Calibrated by Dave".
@lelandclayton54625 жыл бұрын
A cal cert on a post-it note...
@catherinetrudel30855 жыл бұрын
Awesome video, I like how you show that doing EMI measurements is easy. And in my electronics courses they said I'd never do that unless I go to university, yeah... Right.
@Arielo.075 жыл бұрын
Great video Dave! Could you do a similar frequency domain analysis with an oscilloscope's FFT? Just to make it a lot cheaper and accesible, since it's a more common tool.
@LaughingBuffaloes5 жыл бұрын
I would love a video on using FFT function to make these measurements. I think building one of these probes would be a lot of fun for $10. A spectrum analyzer is out of the question for me, and probably a lot of hobbyist, but I do got a scope with FFT.
@janbottorff46425 жыл бұрын
You could potentially use fft on a scope, if you had a scope with 1+Ghz bandwith. A new 1Ghz scope is in the $10k vicinity. A hacked to 3.2Ghz Siglent spectrum analyzer is about $1700. A HackRF SDR is about $250, and I believe with the correct firmware sweeps 6Ghz rapidly. The lower cost devices would not be calibrated or have features like like tracking generator, so the hacked spectrum analyzer has some significant attractions. There are also PC based vector network analyzers, which add a lot of additional functionality, as they measure phase shift in addition to amplitude. A full duplex SDR + a ebay reflection bridge might be a usable vna with the right software.
@eglkFlyer5 жыл бұрын
Love the enthusiasm. How about doing the E field probe next ?
@willyarma_uk5 жыл бұрын
That was ace, enjoyed that. I was thinking u could 3D print a mould for the coating.
@SimoWill755 жыл бұрын
This Dave! This is why we subscribe. Now, can you show how to build a DSA 815 for those of us that can't afford one? Haha
@redtails5 жыл бұрын
hey Dave, I like this video. However it's really unscientific to say 2 responses are "the same" or "identical" when minor differences persist. If anything, they are *similar*.
@johnwest79932 жыл бұрын
Great idea! I just happen to have a box of surplus semi-rigid SMA jumpers (and some with 1 end off,) and 3 or 4 of those little amps, AND some ferrite cable clams, but no EMC probe! I'll do it! BTW, that is braid on the coax cables, but it is saturated with something much like solder, ensuring 100% coverage.
@pablodv875 жыл бұрын
As someone else said on the comments, I'd like to see how an oscilloscope FFT using this probe compares to the spectrum analyzer, for the ultimate thrifty EMI measurements!
@DanieleGiorgino5 жыл бұрын
That's pretty ridiculous. Cool video Dave!
@electronicsNmore5 жыл бұрын
Excellent idea!
@alexmirica5 жыл бұрын
Good job Dave!
@amirb7155 жыл бұрын
excellent video. I hope you make the follow up videos as you mentioned. I would also love to see a differential version of this instead of single ended. I think high end EMC probes must be differential to suppress common mode noise and enhance sensitivity. In the end it can be converted to single ended using a balun or something. Someone asked if this can be used in audio frequencies, I think the voltage induced in that loop must be proportional to frequency as well as the loop area, so at audio frequency, the picked up voltage will be way below noise level
@manickn68195 жыл бұрын
Excellent video. This was quite interesting and useful. Please do the video in compliance.
@WacKEDmaN5 жыл бұрын
them cheap amps are perfect to use for RTL-SDRs aswell..infact you can use this probe on a SDR and find the same results!
@EEVblog5 жыл бұрын
Yes, they advertise them for that
@NickHorvath5 жыл бұрын
You can buy the cans of plasti dip, probably works better than the spray. Also, using a spray paint primer first might help it stick better.
@Hackinside5 жыл бұрын
I love this kind of videos comparations. More videos like that, please. Expensive VS Cheap. Who is gonna win?
@EEVblog5 жыл бұрын
Usually there is a performance difference, but in this case pretty identical!
@Hackinside5 жыл бұрын
@@EEVblog EEVblog I agree. But for a simple mortal like me and others learners, $10 to $300 makes a lot of difference.
@SomeMorganSomewhere5 жыл бұрын
Cat nail scissors are excellent for stripping braid off small coaxes.
@TheNoBSZone5 жыл бұрын
Great video. In the pre-compliance process right now for an IVD device with the cheapest company on the planet.. I seriously hope it doesn't come down to me building one of these. Thanks.
@TheBdd45 жыл бұрын
Great video and the answer to my needs for a cheaper and accurate way to measure fields. I enjoyed the 2 layer/four layer computer boards comparison you did recently but shuddered at the $300.00 Tek probe kit price. I used to make sniffer probes for use in troubleshooting radio xmtrs and receivers which were of course uncalibrated. I consider what you taught us to do here to be close to calibrated. Thanks for the unselfishness.
@EEVblog5 жыл бұрын
Should be pretty close to the performance of the professional Tekbox one. I can do some more detailed measurements and comparison, but it's looks as close as you can get. Although with near field probes you aren't really dealing with absolute quantitative measurements.
@TheBdd45 жыл бұрын
Dave, thank you and here is a project request: Would you design, build and test the efficiency of a a Joule Thief circuit. There have been many offerings but I have never see any commercial products. I recall you commented in the past about the LED in a similar circuit not having a current limiting resistor. Some of the offerings have run a long time on a battery. I have designed my own 1.5VDC non Joule Thief LED "flyback circuit that generates a sine wave that I thought might recharge the battery but did not even though LTSpice indicated that it might. I also have a LTSpice design that uses very little 1.5VDC battery current to drive a LED but I can't get it to run in the real world. Still trying........
@w5cdt11 ай бұрын
I built one too. Works fine!
@michaelhofmann50915 жыл бұрын
Just another grand Video! Very educative and interesting! Keep it up! Good onya Dave :)
@evic2624 жыл бұрын
39 dislikes are from EMC probe manufacturers lol
@alesizzz110 ай бұрын
Well done
@cspower72595 жыл бұрын
Nice little project that one. Thanks for an great video.
@nathanielreid49675 жыл бұрын
A good appropriate spray paint should do the same job nicely as the plastic dip here.
@Ghostpalace5 жыл бұрын
Awesome! Never knew there was just a trace and a plane to it
@Tortillin00775 жыл бұрын
For an electronics engineer doing mainly pcb design for digital high speed or RF applications, how important/relevant is having a professional engineer's licence in getting a job in this field? I ask for those that practice engineering in countries where the profession is broadly regulated.
@MidnightVisions5 жыл бұрын
Those tiny amplifiers are the MAR series from minicircuits.com. They have been around since the late 1970's. This is the MAR-2 line. www.minicircuits.com/WebStore/dashboard.html?model=MAR-2SM%2B
@ThomasHaberkorn2 жыл бұрын
let's say far field measurements come back with a high spike at 200 MHz. Will the near field probes (E or H) also see a spike at 200 MHz ?
@IvoTrausch5 жыл бұрын
Why not get in touch with an institute or university to test it? Our RF professor would certainly be interested in testing such a thing, even just for the lols.
@mrjazzycharon25 жыл бұрын
Would be cool to create a heat map showing how much is radiated as a function of the probe position. What would be the best way to realize that?
@EEVblog5 жыл бұрын
I have several idea, from modding a 3D printer, to a line scanner, to a full array scanner.
@mrjazzycharon25 жыл бұрын
EEVblog Would be especially cool to create a volumetric scan for discerning between near and far field. But anyway, just saying. :)
@krzysztofbednarek94855 жыл бұрын
Thank You .
@samuelscott13615 жыл бұрын
Plasti Dip recommends a primer coating first, I don't know if it has to be there's or if any primer will do.
@cowasakiElectronics5 жыл бұрын
Is it possible to get any sort of useful reading with a scope? I've seen these used for locating dead ICs
@khemrajramsamooj93349 ай бұрын
@EEVblog can you do a tutorial with using an SDR and an EMC probe?
@pavlitt3555 жыл бұрын
The clue is in the name; PlastiDIP. Always better dipped if possible rather than sprayed. Mix and let settle to allow bubbles to come out before dipping. Keep moving while drying for even coating. Buy Pastidip thinners (naphtha) at same time in order to vary thickness (let evaporate to thicken, add thinners to thin). Store in fully sealed container otherwise it will be solid when you come back to it in a few months time.
@michelfeinstein5 жыл бұрын
I just missed a DaveCad with EM fields around the probe, so we can understand better how the fields convert to Volts into the probe, for the signal analyser
@kubaxd255 жыл бұрын
There are some cheep pcb emc probes on aliexpress, maybe test those? Just search for EMC EMI Probe. 50$ for a set of 3 h -field and 1-e field.
@mohammadsarmadi88843 ай бұрын
thank you for your good videos, in some resources has been mentioned that hand made H probes should terminated by 50 ohm resistor. what is your opinion?
@redfishervictoria5 жыл бұрын
When I play our video at 2x speed you become an electronic squeaky madman!
@EEVblog5 жыл бұрын
Play it backward... Dave is dead...
@timwalther5 жыл бұрын
Interesting way of saving quite some money! So, how’s the e-field probe built?
@umpoucosobreconhecimentos5 жыл бұрын
Very useful. Thank you.!!!
@neuralnetwork6535 жыл бұрын
Fascinating! Thank you!
@MedSou5 жыл бұрын
*Very helpful, Thank you* 👍👍👍👍
@thomask775 жыл бұрын
Please do a Rogowski Current Probe next!
@WhatCID5 жыл бұрын
Nice job Dave , Make more hack like this i love it .
@f.hababorbitz5 жыл бұрын
I NEVER found using this type of probe to find where the RE noise was coming from. The noise was everywhere, every component, every power rail. So trying to fix an RE compliance issue was not done with this sort of test gear. We joked that what we needed was eye sight that could see the circuit board in the frequency of interest to find the component and power connections radiating. What I did learn was how to design proper decoupling to each component, and paying special attention to components that drove wide processor bus (octal, 16) paths, as these are charging the circuit traces which is what causes the RE problem in the first place. Our PC design department was useless, as they would just place the decoupling components around the board. We figured out how to source the power for each IC on the PWB, so they were not directly connected to the power planes, but instead to multiple capacitors, which then had power connected to Vcc and such. The inductance of these traces had to be kept minimal. The idea is that the decoupling provided the high frequency currents for charging the board capacitance/inductance. It was tough, as we dealt with non technical board designers, that wanted to turn the autorouter on.
@milantrcka1215 жыл бұрын
It takes a smaller loop - which will provide higher spatial resolution. 2 turns of 32awg (or so) enameled wire on 2-3mm dia (wire wrap wire also works), 50-ohm resistor in series and coax. Preamp required. Works well.
@f.hababorbitz5 жыл бұрын
@@milantrcka121 I never found any ability to find the source of the emission as any quantitative measurements were "noise here, and more noise there". The circuit boards were 150mm X 250mm. In 1988 the processor frequencies were 6-10MHz, but this morphed to 32MHz, to 128Mhz. The lab had multiple HP brand probes. When I was still green starting out, the technicians just laughed, as they knew the root cause of the emission was not found by this method. The RE plot would show which processor frequencies were the source of emission limit exceeded. So we would try to bandaid the boards with capacitors and such. In the end, these original designs were ultra crap, and the fix was a new board layout. My job was to integrate a card cage of 19 microprocessors and make it pass the environmental requirements. This was avionics, the test methods were from RTCA DO-160 (version G when I retired). There were very deep notches to the RE bode plot at the comm radios, and nav radio frequencies. And super position of the emissions from these processors was a challenge.
@milantrcka1215 жыл бұрын
Well if the emissions are everywhere, then the design has a major problem as described. Been there, fixed that.
@barrykery11753 жыл бұрын
Great video. Question: "How many volts are needed to power the Low Noise Amplifier?" Barry
@k1mgy5 жыл бұрын
Was hoping you might go into this a bit deeper. Thanks!
@EEVblog5 жыл бұрын
In what way?
@ThatEgghead5 жыл бұрын
EEVblog not the poster but I loved the video but I would also love, maybe in a follow-up, how/why the probe is designed that way, why the symmetry and impedance matching are so important. In any case, I'm loving the EMI/EMC series!
@MastroGippo5 жыл бұрын
@@EEVblog I'd guess he meant it as "after watching the previous video, I was hoping you would dig deeper. Thanks for doing it! “ as that's what I feel too. And please keep them coming! :)
@qzh00k5 жыл бұрын
You could characterize the two amps for frequency response, that might be the only tech difference.?
@PilotPlater5 жыл бұрын
know it's not the right way to do it, but maybe a video on using these probes on a normal oscilloscope. Mine has the FFT functionality but not sure how much useful info you can get with this setup