#286

[@fmashockie]

your section on triggering was the best explanation I've heard. For some reason, triggering was difficult for me to understand when I first started using a scope. Wish I had found this video back then! Still it was a great refresher - thanks for sharing!

[@BillyLapTop]

Wow, the Fairlawn Amateur Radio Club! I used to attend the Friday night meetings back in 1972 at the recreation department location, when I lived in North Jersey. Can't believe it has been so long ago now. Lots of father and son members then. I'm glad to see they are still around. Your presentation on oscilloscopes was in the same vein as the presentations I remember way back when. The topic of the day then were the up and coming amateur satellites and other technical matters. It was a great club then and I can see it is still a great club now and it was gratifying to see a nice turnout for your presentation too and the quality of the content is still great. Thank you for your presentation OM.

[@austinjunkman2449]

2 nights ago I dug my 2465 DMS out to fire it up and see if I can make heads or tails out of it. Last night after figuring out enough, I took pictures of it working so I could sell it because I thought it was above my pay grade. Today I'm looking at some forum post on antennas and found a link to this video. The forum said he works for Tektronix, some of his first words are "today I'm in FairLawn" and he is doing his demonstration on pretty much the exact same oscilloscope I can't figure out. I grew up in FairLawn. Mind Blown. I guess it's a sign to keep the scope and learn all about it and use it. That building has changed quite a bit, it used to be called the Rec center. The water tower was right around there and we used to visit Bojangles the Saint Bernard, that lived at the water tower, that seems to have been torn down. what a trip. Thanks. You have a new subscriber.

[@craxd1]

The first "memory" was done a bit differently than today. It was developed by providing a wire grid behind the phosphor screen of the CRT, and where the electron beam struck the screen, the grid fed that X-Y value back and stored it. I'm not sure if that was a Tektronix invention, but the old 7000 and 400 series used a memory system like that. Waveforms were captured by a Polaroid camera. I have a small Tek handbook about that around here somewhere, and I still use a 7000 series scope once in a while. "Tektronix 7000 series oscilloscopes have high-speed trace retention and long display times that can last for hours or days." Actually, Tek had an entire series of those handbooks in paperback, and they are a good read for anyone wanting to learn the secrets of scope development.

[@michaelmurray3422]

Now that was great.. I learned a lot of new and useful things I was not aware of. I will be using my scope more often then I used to. I have a digital scope that quit working, and now I will try to get it up working again, and use it as well. Thank you very much for sharing that with us!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Michael

[@Radiowild]

Nice little "wake up " check at the end! Great presentation as always.

[@clint-ws1v969]

Heathkit in Fairlawn, some of my very 1st foray in Ham radio... great memories...!

[@robertcalkjr.8325]

Nice basic overview. Thanks Alan.

[@robertcalkjr.8325]

I guess the youngsters are too busy playing video games...

[@gordonwedman3179]

Nice to see a professional at work. Couldn't be done better. Thanks.

[@richardlee5342]

Great presentation as usual Alan! Richard Lee Pres. NJARC

[@ijskolibrietje]

Thank you so much! I'm just starting out and I just got an old scope to try things out.

[@basspromike]

How come my modulation wave form is just lines and not bubbles?

[@w2aew]

It could be a couple of things. I assume that you are looking at the RF envelope of your transmitted output... It is possible that your horizontal scale or sweep speed it set too fast. Or, if you are using a digital scope, it is possible that the scope sample rate is too slow and the signal is being aliased.

[@obdanton69]

You have suchs nice and educative videos. I really enjoy them. Often with a cup of coffee :-) good work

[@lindenlonstrup3326]

Very nice. Very clearly said. Thanks!

[@toniturnwald9890]

Excellent explained, thank you for uploading / sharing. cu Toni

[@joopterwijn]

About to pick-up the “hobby” again, nice to get a reminder/re introduced lesson scopes. Must Admin that the sound was a bit hard for me, probably perfect for the audience but maybe a cat-mic with a recorder on your belt if you want to use a presentation later on also as video.

[@billwilliams6338]

Do you have any videos on explaining how to use a logic analyzer to measure data busses, address busses, test ROM and RAM chips, test multiplexers, adders, address decoders, counters. Using a logic analyzer you can display all the inputs and outputs and count the highs and lows to get the Hexidecimal values. It would be nice to know how you troubleshoot digital electronics since i haven't seen any digital theory videos or troubleshooting in digital electronics by you.

[@AlexT0920]

Could you share the powerpoint file? Thanks

[@blakegardner2339]

9:33 Why do you need a 50 Ohm input impedance on the oscilloscope to measure RF signals?

[@w2aew]

This video should help answer that question for you: kzbin.info/www/bejne/nZDNqZtmhsqSfLs

[@rbmwiv]

Great video. Very informative, I have a dso and a old Tek analogy. I really like using the analog better. You learn to do more in your head using a analog where it doesn’t give all the measurements a dso puts out. It’s information overload.

[@bigfoottoo2841]

Wish the audio had been recorded better.

[@42BillD]

Hello Allen, I love your videos, keep them coming. I am looking to get a scope for use with 2 meter 144MHz band. Is a 200MHz scope good enough to properly examine 144MHz frequency output of an RF amp or do I need a scope rated for higher than 200MHz ?

[@w2aew]

In order to visually see distortion on the output, you'd need a scope with at least three times higher BW than the signal. Frequency measurements will be fine, although a scope isn't the best tool to make frequency measurements.

[@felixcat4346]

Very nice presentation. I would like to comment that, really a digital scope is better than an analogue. So for me and a would say for most, this holds true, so its not really a debate anymore. The evidence for this is what big company is making analogue scopes. They made that decision for us many years ago.

[@wadepatton2433]

Of course new and fancy is better, but some hams don't care to spend those bucks and can get by with old and crotchety in order to sort out their rigs and other projects. Now that I have a teacher, I'm not afraid to bid on an old dusty scope, but I have no biz buying a new one.

[@gordonwedman3179]

The old analogue scopes are often repairable while digital not so much.

[@InXLsisDeo]

Alan works for Tektronix. Believe me, he knows his scopes inside and out.

[@EdEditz]

Wow, you're a very good teacher Alan. The extent of your knowledge is impressive. I have one question though, A scope usually has 3 input coupling options, AC DC and Ground but in what situation would you use ground? I'm pretty new to using scopes and this is something I always wondered about. I watched the whole video but I didn't get an answer out of it (or maybe I just missed it).

[@p_mouse8676]

EdEditz . Mostly I use the ground option to set (or remove) the offset, since it's not always clear with a signal on it.

[@EdEditz]

Ah right, that would make sense. Thank you.

[@electronic7979]

Useful video

[@coffeecuppepsi]

here's a question, i can't afford a good oscilloscope, but i would like to have one for my VHF projects, so say 200MHz and 5uV/divison... i have access to a 50MHz 50mV/division. so because the signals i want to view are periodic, may i use a mixer and amplifier, so say shift my RF down to 20MHz and amplify it by 10,000 and use the low end scope? is there such a project? has anyone here done that? or advice how to proceed, cheers :)

[@w2aew]

Just to let you know - you're not going to find any oscilloscopes that will give you 5uV/division - they just don't make them with that kind of sensitivity. Typically you'll see sensitivity down to 1mV/div or 500uV/div, but not anything near 5uV/div. Scopes just aren't used at this small signal level. Spectrum Analyzers on the other hand, can see such small signals...

[@majdibh4383]

Hey W2AEW! I'm a big fan of your page and work from 3V! I'm working on making and testing my own toys and to be honest, many of your videos made my life so much easier! There is only one thing that I couldn't figure, and kept me busy for quite sometime, in your gilbert cell videos.. Could you please spare some of your time to explain it to me? I would immensely appreciate it! I need to make that Gilbert mixer!! Majdi 3V1M.

[@w2aew]

I assume you've watched the couple of videos I have on the Gilbert Cell. What questions do you have?

[@majdibh4383]

Thank you so much for reacting to my comment!!! It's been a year since I've seen them among many of your videos! and I came across them again lately.. Anyway I've a sticking project; I've worked on a Gilbert mixer, i know the theory behind it, but I've never managed to make the cell's bias! How did you calculate the resistance values required for bias?! what methods did you rely on?? i tried to make the upper diff amps based on voltage divider bias, but never managed to make the lower diff amp bias!!! nor did i manage to bind its collectors with the upper diff amps!! I've looked all around even in different languages but all i found is theory about the cell, but nothing on how to actually make one! I've been stuck ever since! I'm working with an 2N2222A.. I'd appreciate any help or info you can give me! Thank you! best 73s

[@w2aew]

If you don't cross-connect the collectors from the upper differential pair, then you don't have a Gilbert Cell! For your reference, here are the two videos on the Gilbert Cell: Basics: kzbin.info/www/bejne/bZ_QnpVmpdaHi5I AM and DSB-SC Modulation: kzbin.info/www/bejne/aWmygqiYZ7ucaLM ...and the notes pages from each: Basics: www.qsl.net/w2aew//youtube/GilbertCell.pdf AM & DSB-SC: www.qsl.net/w2aew//youtube/GilbertCellModulation.pdf The notes pages show the biasing scheme. I used a simple resistor string to setup the bias for the upper and lower diff-pairs. The main considerations for setting up the bias are: 1) make sure that each pair is in the active region when the diff-pair is balanced - thus make sure that the IR drop across the collector resistors puts the collector voltage above the base voltage of the upper pair, and 2) ensure that the common emitter voltage of the upper pair is above the base voltage of the lower pair.

[@majdibh4383]

Thank you so much, I am so sorry for the late reaction to your comments as I've been really busy lately. Anyway what made difficult for is that in most of the documents I have, the bias requires a +vcc for the transistors, except that when looking at the tail transistor, the collector is connected to the upper pair's emitter than the vcc, and that made me really confused! I really appreciate your help, advices and the links you provided! Will definitely get busy working with them! Thank you so much! Best 73s de 3V1M! :D

[@ronaldoEscalanteCruz]

Came here to give your video a like . I feel so petty but you deserve it.

[@stefflus08]

Ooh you have 555 likes, I can't ruin that. But I like all your videos.

[@meatfoot4803]

Kool bro Tysm.

[@bozon354]

Круто!