In 91 yrs of my life; I have never seen another like Paul. He is truly a "Cut-Above". Thanks Kind Sir for sharing your talents with us.

@MrCarlsonsLab

Жыл бұрын

Thanks for your kind comment Pat!

@akepatinagaraju8564

3 ай бұрын

Great man

I have been looking at getting an active probe recently so this is great timing for this old video to pop up on my feed today. I may try a diy solution like this for fun. So thank you for the full explanation and circuit. It helps to have some ideas of what to expect vs an off the shelf version. Keep up the great work. I have been a long time subscriber and you have great depth of knowledge.

I hope this guy works for a respectable testgear company and he is paid a lot for his work, cause he has a huge bag of knowledge!

@radioguy19510

Жыл бұрын

He's worth whatever he's paid.

Amazing Paul, your explanations are crystal clear, your English accent and the talking speed are so comfortable. Again Paul, thank you very much for your videos, I hope to support you in the near future.

@MrCarlsonsLab

3 жыл бұрын

Many thanks!

I just love your lab, Mr. Carlson. :) Thanks for sharing.

Always professional and a joy to watch.

Great design, Mr Carlson! It takes a lot of knowledge and experience to do this.

Thanks for sharing Paul, your lab makes me happy! This probe is awesome.

@MrCarlsonsLab

8 жыл бұрын

+saturn5tony Thanks Tony! Glad you enjoyed the video.

great video....i learn a lot of stuff every time i see your videos

Thanks for all of your efforts. I think a lot of us out here are very grateful.

@MrCarlsonsLab

8 жыл бұрын

+Thema inproblem Your welcome!

Another excellent and interesting video! Thank you Mr. Carlson

Wow, such a simple design for such a great tool. Thanks for all the insight.

@MrCarlsonsLab

8 жыл бұрын

+Justin L. Your welcome Justin!

I very much enjoy your videos and you are a wealth of information! Thank you.

thats so neat how gifted you are with electronics.

This is exactly what I need right now, and Mr Carlson delivers! (Yes, I realize it's years later, KZread algorithm works in mysterious ways...)

Hi Pat. I realize you have a very significant subscriber base so no reply is just fine. I just have to say that your incredible knowledge is such a pleasure to see. Above and beyond that, your kind demeanor is a tribute to you and your life choices. Just found your channel and now I’m going to have to visit everyday for as long as it takes to make it through all your presentations. Take care and thank you for being such a fine gentleman!! Oh and Patreon is a no brainer for your channel! I’ll support your channel through that app . Andy

Great video. I really liked the impromptu tour of the working lab.

@MrCarlsonsLab

8 жыл бұрын

+Michael Lloyd Thanks Michael!

Another excellent video, always impressed by your extremely tidy printed circuits.

@MrCarlsonsLab

8 жыл бұрын

+g0fvt Thanks! That toner transfer method works well.

As usual, very interesting , congratulations good video!

Nicely done Paul. You are a superb teacher and I've leaned a lot from you. Greetings from Arizona.

@MrCarlsonsLab

8 жыл бұрын

+Thema inproblem Thanks for the kind words!

Excellent video. "behind the scenes" looks so familiar :) Thank you for sharing knowledge. This is priceless.

@MrCarlsonsLab

8 жыл бұрын

+Robert Gogol Your welcome Robert!

+MrCarlson, thank you so much for this video and for your channel. The content is excellent, presentation is impeccable, and pace/depth/completeness is unlike anything on KZread. Kudos and thank you!

@MrCarlsonsLab

7 жыл бұрын

Thanks for your kind words Cody!

Great video. Love the behind the scenes. Thanks.

@MrCarlsonsLab

8 жыл бұрын

+PelDaddy Glad you enjoyed the video!

I just found your videos and I LOVE them....please keep building

@MrCarlsonsLab

8 жыл бұрын

Thanks! I will as time permits.

@JagjitBrawler

8 жыл бұрын

Just curious, did you major in EE and are you an EE yourself or is this just a hobby for you. Im a HS student rn but I really want to get into either electronics or coding

great video of the skilled work you do But me being very knew to all this rf radio related stuff its still blowing my brain cells to bits ....keep up your brilliant channel ...

@MrCarlsonsLab

8 жыл бұрын

+retro80s Thanks!

Thank you very much Paul for sharing this nice video with us.

@MrCarlsonsLab

8 жыл бұрын

+esmaeil nam Glad to share Esmaeil :^)

Dear Paul, you seem to lead a charmed life full of horse shoes. " I just happened to have an input probe with an adjustable cap floating around in my stuff." The packrat in me is envious of your awesome collection of gear. Well done my good man, well done. My grandfather, who lived thru the depression, impressed upon me the value of repair and to never, never, throw away something you might someday use.

@MrCarlsonsLab

6 жыл бұрын

Thanks for your kind comment Gary!

Nice little probe. But your lab, Mr. Carlson... that is a slice of heaven. I could see myself getting lost there for days and admiring those beautiful test equipment. Magnificent! :) Thanks for your time!

@MrCarlsonsLab

6 жыл бұрын

I'm glad you're enjoying the video's! Thanks for your kind comment.

Very interesting presentation. Thanks for sharing.

Interesting project.. Big thumbs up... Can wait for next videos..

@MrCarlsonsLab

8 жыл бұрын

+Jurva-Markus Vehasmaa Thanks Jurva-Markus!

I feel MUCH better about how cluttered my shop gets when building a project. Although, your "messy" lab looks better than my lab when organized LOL. Thank you!

@MrCarlsonsLab

7 жыл бұрын

Glad you enjoyed!

Enjoyed the extra video at the end, I think most of our shops get messy when working on a project. Glad to know your human. 😀

@MrCarlsonsLab

8 жыл бұрын

+Chuck Legg LOL, thanks Chuck!

Wonderful, thanks for the clear explanation!

@MrCarlsonsLab

2 жыл бұрын

You're very welcome!

Really good info. Thanks, Paul!

@MrCarlsonsLab

8 жыл бұрын

+Mike Lentsch Your welcome Mike!

I loved trying to follow along to this one!

@MrCarlsonsLab

8 жыл бұрын

+Shaunak De Glad you enjoyed!

That's wonderful design....... Keep going.... :)

I too have a 3585B, my favorite pies of test equipment, and it is Heaven for working on HF rigs and designs, as well as audio and high frequency vibration analysis.

Thanks Paul. It must be nice to have such a great lab!

@MrCarlsonsLab

8 жыл бұрын

+Robert Calk Jr. Thanks Robert!

Great one! Thanks!

Great vid. Thanks for showing round the lab.....looks like a scene from an old Vincent Price movie.

@MrCarlsonsLab

8 жыл бұрын

+notionSunday LOL, Thanks!

i refrain from skipping ads on your channel - although i do kill the annoying audio. my way of expressing respect and gratitude to you.

@MrCarlsonsLab

7 жыл бұрын

Thanks!

Oh, okay, now I see what is going on. Had to rush out for a while and missed the last part. Caught up now. Thanks.

Very good work thank you for sharing

@MrCarlsonsLab

8 жыл бұрын

+DENNIS N Your welcome Dennis!

One thing to note here is that the output impedance of this circuit is not 50 Ohms. It is in fact very small, even smaller than the re of the bipolar because of the shunt feedback from the Opamp. You need a series resistor at the emitter of the bipolar to the output. It would reduce the dynamic range, but provide improved frequency response.

@MrCarlsonsLab

7 жыл бұрын

There are actually quite a few reasons I built the probe in this manor. Normally, I would add that 49.9 Ohm resistor between the emitter and the cable center conductor. I could write a book at this point, right down to the differences in the op-amps (same part #, different results) One of the major reasons was that dynamic range reduction. This probe originally had a specific intention that can be viewed in the CRF-320 video. The probe was to be flat, and unity gain (or close too) within a small spectrum, adding that resistor complicated matters, found through experimentation. Thanks for stopping by, you have an interesting channel as well!

@Thesignalpath

7 жыл бұрын

Thanks! I assumed that you were already aware of the output impedance. The comment was meant for someone who may be skipping through the video and would mistakenly think that the resistors at the emitter would provide 50-Ohm termination. Great work, your patience in your restoration videos is admirable!

@christophschuermann6512

6 жыл бұрын

Mr Carlson's Lab first of all: great video! I undestand both of your explanations regarding the output impedance. If you make a sweep with a 50 Ohm generator into the output of the circuit with the input shorted (50 Ohm would also work ;-) ) you may get surprised. Its all about the flatness of the whole system. Best regards and thanks for your great work!

A lot to take from this great video. Would be nice if you could start a series like fundamental Wednesday or some day on RF stuff, loads to learn from. Specially for those who are more into embedded, power or controls world. Great work!

@MrCarlsonsLab

8 жыл бұрын

+Syed Mazahir Rizvi Thanks for your input Syed!

This looks like a fun project and I'd be interested in building one of these. I believe Paul mentioned in one of his recent Patreon videos he may have an updated version of this project in mind. I'll be very interested to see what he might have come up with.

Excellent video, as usual, thank you Mr. Carlson.

@MrCarlsonsLab

6 жыл бұрын

You're Welcome Gort!

Paul, Wow! that was pretty amazing. I love the way you explain every step along the way. And the circuit you built is very clever. Also like the way you utilize every piece of test gear. I am also looking for another spectrum analyzer. Really in the need for a more modern one with tracking generator. The old IFR 1200 just does not cut it since there is not tracking gen. he option is about a grand but still no onscreen display. I want to be able to do some V/UHF duplexer tuning. Plus want to homebrew a 4 cavity VHF duplexer :)Great job as always my friend.

@MrCarlsonsLab

8 жыл бұрын

+The Radio Shop Thanks Buddy! That IFR 1200 is still a real neat piece of equipment. Take care!

Excellent job Paul! really all thumps up as I exactly know what it means to do a build like this. wish I had a bit more time.... Take care and talk to you soon 73

@MrCarlsonsLab

8 жыл бұрын

+TRXBench Thanks Peter!

THANKS Paul, another excellent video!

@MrCarlsonsLab

8 жыл бұрын

+old64goat Your welcome!

Great video - THX!

I would enjoy knowing how you distribute power to all your test gear... especially the grounding system... as well as protection for over voltage between and during work sessions. Consider a video on that subject! Thank you!

My wife collects closets full of clothes but this gear is really worth it!

Im sure you had pleanty of offers,your a smart person wish i had your brains.

Fantastic project and again an excellent talk! Thanks for sharing! Just one question: why not have the runner of the 1k connected to the minus input of the opamp and the high end towards the output?

Another think to note is about the 1K potentiometer. It do not chage the gain, it just modifie the current in the output transistor. IF instead of that you replace it by, for instance two 1K resistors with the - pin in between, or better you put directly the minus pin at the juction of two output 100 ohms resistors, your gain will be x2. In such a way you could add a 47 ohms resistor at the output. Then loaded by 50 ohms, the gain will be equal to 1 and maybe the small variable capacitor you put add the end will deseapper because the emmiter of the output transistor will be really loaded by 50 ohms and not byt the capacitance of the cable.

I love all your videos, Paul! You've taught me a lot! This week I plan to build a couple of your spectrum analyser protection devices to use with my HP3585A to align my SP-600 IFs. By the way, has anyone ever told you that you look like Vinzenz Kiefer?!

I can't believe you have only 20k subscribers. Information on your channel is priceless. Dave from eevblog could learn from you and still his channel is larger. It is not fare.

@cny02253

8 жыл бұрын

Paul is much more hands on, analog and RF oriented than Dave. Dave has teardowns and explains newer tech from a very armchair and consumer perspective but Paul is more oriented to people who actually do build, are hams, are advanced experimenters etc.

@robertcalkjr.8325

8 жыл бұрын

+Martynas Mirauskas Yeah, and Paul doesn't attack the personal beliefs of people. Which wouldn't be so bad if someone did, as long as they provide some basis or facts for their accusations. But as far as I'm concerned, to call someone stupid for their beliefs and not provide any facts to back it up, is the hallmark of lunacy.

@rubusroo68

8 жыл бұрын

+Martynas Mirauskas big difference in output. Mr Carlson is far more detailed, he's like +TheSignalPathBlog Dave is just entertainment.

@mrjohhhnnnyyy5797

8 жыл бұрын

+cny02253 I don't consider myself as an 'advanced tinkerer', but I just love the amount of detail in Paul's in-depth videos. Alan (w2aew) also provides great explanations, I learned heck of a lot from his vids; at the end - Dave is like a pop music, has a larger audience, but not as pleasant as other genres; but great for entertainment sake.

@darqen271

8 жыл бұрын

+dr. Chernobyl Dave is knowledgable, but he is spoiled by all the freebies and money he gets for reviewing products.

I have got the impression that you love measurement equipment, and dont need to think about room temperature in wintertime....

Isn't it amazing how everyone knows where everything is in their labs but search the kitchen for a mug to make coffee.. hihi P.S I am learning so much from you videos, thank you. vk2wgw

@MrCarlsonsLab

8 жыл бұрын

+Glenn Wilson Glad your enjoying Glenn!

Paul, fantastic project as always. Would love to get a SA one day (or repair one).

@MrCarlsonsLab

8 жыл бұрын

+rupert handford Thanks Rupert!

Amazing stuff! Love your lab.

@MrCarlsonsLab

8 жыл бұрын

+Justin L. Thanks Justin!

Very good video..

@MrCarlsonsLab

8 жыл бұрын

+Daniel Stimpson Thanks Daniel!

I'm curious to know how the 1M resistor on the input of the op amp is determined. Thanks.

great video thanks

@MrCarlsonsLab

8 жыл бұрын

Your welcome!

I like the sound of the probe you are talking about at 9:00. This was a great video a learned a lot as always. Thank you so much for all the hard work and effort you put into these videos. You make learning a pleasure.

@Daniel-ib5bx

8 жыл бұрын

Nice lab!

@MrCarlsonsLab

8 жыл бұрын

+Daniel Rogers Thanks Daniel!

Your video series should be a show on the Discovery channel. Seriously - many people learn from you (myself included). Many more can too :)

@MrCarlsonsLab

8 жыл бұрын

+Ron C Thanks for the kind comment Ron!

The active probe would be a nice and useful item to have in my collection of test gear. I checked eBay to get an idea on the price of an HP 3585B. I found one but the seller wanted more than the price of a new Rigol DSA815-TG. :P One of these days I would like to buy a spectrum analyzer. Spectrum analyzers are rather expensive beasts so I'm more likely to have a go at making a basic one from scratch. I don't need one that covers more than about 0 to 500MHz.

Paul, fantastic, and just what I was working on RF Probe, But wasn't keeping those Tol., Sorta Got a Chuckle, at the ending sweep of camera wondering if the little Young lady came in the Door and seen it , What her words would be? lol lol Yea just a little project what it can do to your Bench area lol Yes enjoyed it and saved this one for future Special RF Probe I may need . Yes keep them coming , man the hits on you unbelievable. 73's .

@MrCarlsonsLab

8 жыл бұрын

+Ranger Dale Thanks for the kind comment! Glad you enjoyed Dale.

Great job, congratulations. I would like to see an active probe for a wider band.

Great video! What electronic design and layout tools do you use?

Actually, for headphone users the camera's microphone seems far better because is not picking up all of the breath-in noises :) anyway greath channel, you're a fantastic teacher.

@MrCarlsonsLab

8 жыл бұрын

+franzgol Thanks for your input!

Is there any way of getting a copy of the drawn PCB design, as it is so critical for a successful (first time) outcome? regards Bob_R

Very well presented Paul. I liked the comparisons you used in the circuit design explanation for us tube guys. Every little bit helps thank you.

@MrCarlsonsLab

8 жыл бұрын

+hankus253 Thanks Hank!

Good info.

@MrCarlsonsLab

8 жыл бұрын

+wade hicks Thanks Wade!

awesome!!!

@MrCarlsonsLab

8 жыл бұрын

+Damian Molina Thanks Damian!

The 3SK74 are done now, like so many parts.

Thank you!

@MrCarlsonsLab

8 жыл бұрын

+Rob H Your welcome Rob!

What would you recommend as a replacement for the fet? What charasteristics should I be looking at when picking a replacement for this spesific fet? Thanks you, awesome clip!

Awesome.

@MrCarlsonsLab

8 жыл бұрын

+Raymond Earle Thanks Raymond!

Hi, great video. I am wondering, why the need for the source-follower FET on the input stage? Couldn't you AC couple the probe tip directly to the LT1812 input? Seems like this would avoid some potential bandwidth loss and gain uncertainty in going through the FET. Why is the FET stage needed?

Thank you for the excellent video Mr Carlson. I see that your probe will have very light loading on the circuit under test. Did you ever quantify the input impedance of your probe? X megohms and Y picofarads? Thank you

hi Mr Carlson! is it possible to have a copy 1:1 of the printed circuit board? THANKS! and...Happy New Year! i2NDT Claudio

instead of parallel protection diode would it not be better to be in serial? to lower th capacity and leakage ?

Hi Mr Carlson, good video. You forgot to mention I think that the inductor blocks RF from leaking out your DC path. I am not familiar with the two gate FET. I understand that you can hook it up; to build some advanced gain circuit, but why did you pull the gate to the drain instead of the gates together?

@MrCarlsonsLab

8 жыл бұрын

+Daniel Johnson Richard is correct, the second gate is commonly used for gain control or mixing. Since I'm using this as a source follower, I just tie the 2nd gate to the drain.

The LT1812 is a 100MHz unity gain stable low output impedance opamp. Only works because the gain is so low.

@0MoTheG

3 жыл бұрын

It already has high input impedance so I do not understand what the FET adds to the design. All it does is the same as a capacitor would.

Dear Paul, I am sorry to say whether for good or bad, we took a poll and have decided to clone you. Keep up the great work for the followers. Bill

@MrCarlsonsLab

8 жыл бұрын

+Bill A LOL! Hey, id get twice as much done.... That would be great! Thanks Bill! :^)

Thank you!....., You (yet again), just saved me a pile of trouble having to do this myself from scratch!....... I just haft to figure out where to etch your name?, on the board of my build of your probe lol.

@MrCarlsonsLab

8 жыл бұрын

+ytrewq6789 Your welcome! LOL, my name is to big for the board size :^)

Great video and a very good looking soldering!

@MrCarlsonsLab

8 жыл бұрын

+senohpi Thanks!

I am wondering if the gain control is shown correctly... Normally, I would expect that the top of the potentiometer would be connected to the output emitter follower and the "slider" would be connected to the inverting input...

Cant beat Mr Carlson's explanations. Thanks!

@MrCarlsonsLab

8 жыл бұрын

+Ignacio Simón Thanks Ignacio!

Hi what software program do you use for your boards?. Thanks.

That flat response for the If's is super. What kind of microscope do you use ? Looks ideal for work on small circuitry.Very well kitted out lab an when ya see a mess ya know there's good R&D goin on.

@MrCarlsonsLab

8 жыл бұрын

+Tom OConnor Thanks Tom! The trinocular microscope came from a university, unfortunately the name is no where to be seen.

Nice vid, thanks . Question tho , what is that huge grey enclosure in the corner ? looks like a 10kw am tx ;)

@MrCarlsonsLab

8 жыл бұрын

+Chipz0r Its an old GATES transmitter :^)

Hi there Your probe is amazing . I do alot of audio work for a hobby . Do you have a kit of this probe mainly for the circuit board as this would be great to build . Thanks John

@BruceNitroxpro

5 жыл бұрын

John Weegenaar, Paul has been asked if he has kits or boards of any of his projects and his answer is usually a 'no' with some sort of suggestion that the maker should make boards themself... in other words, "NO."

I need something that will work from audio to 10 MHz, can this be modified? I want the high input impedance and 50 Ω output. I have RF meters that have a 50 Ω input and want a High input impedance probe to connect to them.

I am all ways inpressed by your printed circuits board!! Question on the schematic on the op amp on the + side is that side going to erath !! thank you terry

@MrCarlsonsLab

8 жыл бұрын

+terry uren Hi Terry. The plus symbol you see on the op-amp is the non inverting input. The supply connections are not shown.

More more more!

@MrCarlsonsLab

8 жыл бұрын

+Donald Holben Glad you enjoyed Donald!

I did enjoy it, though I suspect not as much as you did! :)

@MrCarlsonsLab

8 жыл бұрын

+Pablo Padilla Thanks Pablo!

Very good Paul! Wondering if you have ever thought about getting a file sharing account of some sort to post PDF's (like Alan W2AEW does) or drawings, schematics, PCB art, etc.? Anyway, instead of using a SG, one could hook this up to a sweep generator and look at the output in X-Y mode on an oscilloscope, sorta like we can with filters? (Keeping our impedance ducks in a row of course.)

@MrCarlsonsLab

8 жыл бұрын

+cny02253 Thanks! I'm thinking of setting something up (file sharing) But it's all about time. Using a sweep generator and a scope would be just fine, as long as you know your 3DB down point, and your test set up is flat.