Thank you very much for replying. This leads to a follow-up question: Ok, so the BW limit can in some cases clean up the signal I see on screen if there is any noise to it. But is this "clean-up" happening pre- or post-triggering? If the high-frequency noise is causing trigger problems (triggering on the noise as well, showing "two" sine waves as lobes on screen), can BW limit help me with that?
Would a 2230 have been able to spot that oscillation? It might not have been able to fully resolve it due to the 100 mhz bandwidth but would the blurred trace be evident? I guess I need to build something similar and find out. Is that something that the choice of test leads could affect as well?
Nice video, but I think, the oscillation has started after you have connected the probe to the base of the transistor. And a little tip: dont use ceramic high capacity capacitors in low frequency circuits. The ceramic is highly non-linear this means it changes its capacity when the voltage above the capacitor changes. This leads to disturbances and additional harmonics in the circuit.
My belief is that there are two equally true statements, not just for bandwidth, but for anything in life. 1. "Buy as much (best, etc) as you can afford." 2. There is no such thing as a starter or beginner anything. Learn on the best you can afford (back to statement 1.) My first scope, a 2467B, was no more difficult to learn on than a 465, or any other. When you don't know anything there are no bad habits to bring to the table.
A 2467B is a heck of a scope to be your "first" scope! I remember buying them "new" at my first job in the mid/late 80s, and they were over $12,000 due to the special microchannel-plate CRT.
@@w2aew Gotta learn on something. I love that scope. I'll never be another you, but in the 8 or 9 months I've had it I've kicked butt in learning it, mostly from watching your videos.
Now I'm going to spend even more on my new used scope this coming hamfest. Thanks Alan! No seriously, very concise and practical, not to mention tons of fun.
If you have to make do with a low bandwidth scope, you can in some cases detect oscillation by holding your finger, a metal tool or a piece of ferrite close to the circuit. If this has any effect on a waveform or or on the supply current of an AF circuit, it is oscillating at RF.
Could you do a video of checking capacitors in-circuit using a scope and function gen? This would be very helpful for a lot of viewers and I don't see good video postings anywhere of this topic. thx!
Thank you for all your awesome oscilloscope videos. A question; In what kind of situation could you actually take advantage of the 20 MHz BW limit button? Why would I ever want to limit the bandwidth on purpose? Why is the button even there? I have a 100 MHz analog Tek scope and would really like to know at what point I can benefit from this function. Thanks.
10 years later. I think when you wanna filter out high freq unwanted signals above 20MHz like noise spikes and stff, u would want to turn on the 20MHz BW limit. In the video, the signal is only a few KHz of a sinusoidal signal so u wouldnt see any significant difference when turning on 20MHz.
Excelent video. It proofs the concept - It is always good to have more bandwidth in the scope than needed. I've bought a Tektronix 2465B a few days ago for less than $500 from eBay. Post more video about scopes, I will watch them with pleasure Thank you
Another Interesting Video that you actually LEARN something from, And it Doesn't hurt that You're a Tektronix Application Engineer!!! Tek Scopes are my Favorite( I own a 2225) Thanks!!!
Hi Alan, thanks for your great video! I want to buy tek2467 but also see tek2467B in the market. So which one should I choose? Because I remember you mentioned 2467 with great CRT display, right?
For monitoring the RF envelope, you don't necessarily care about having accurate amplitude measurements, so you can use a scope that has lower BW. A 20 or 25MHz scope would be fine, but a 50 or 100MHz (or greater) would be better.
So, I'm about to realise that tight stiffing circuits on breadboard is wrong idea. It's parallel lines have strong interference and can cause faulty behaviour. Especially on cheap noname boards with uncertain contacts. And is it good practice to create virtual screening, separating different circuit junctions one from another with grounded unused lines of breadboard?
Would you know how I could increase the bandwidth of an oscilloscope? I might be buying a 15 MHz scope, and I was thinking maybe if I'd want, I could increase its bandwidth. I have the schematics (Telequipment D65), so I thought I could just look on D66 and put all parts different on the D65 and that should increase its bandwidth to 25 Mhz (D66's bandwidth). Or I could go look on some other Telequipment scope and get the parts and put on this one and increase its bandwidth. What do you think? PS: I was also told I could be limited too by the CRT. So I guess I could increase it to for example 100 MHz and then let the CRT decide where it could take me. Good or awful idea? haha In any case, thank you for the video!
If you compare the service manuals (schematics and PCB layouts), you can determine if they 15MHz version is intentionally BW limited down from 25 or something wider. However, keep in mind that even if you are able to convert it, it would likely need tuning/calibration to be flat over the rated BW.
@@w2aew Thank you for the fast reply. What components do you think that will need replacement if I attempt to do this? Caps, inductors and transistors? (The ones that came to my mind that rely on frequency - in the case of transistors, for the gain.)
Hmm, I don't have this circuit assembled anymore. I guess that the magnitude of the oscillations will appear lower due to the lower BW. I think that the delayed timebase probably won't have enough brightness to perform this much magnification on the oscillating section.
That's right - I used to have an annotation in the video that corrected this mistake, but TH-cam eliminated the annotation feature. The schematic is drawn properly in this video: th-cam.com/video/IcrnXRbkLpc/w-d-xo.html
Just a noob question (all be it from a 52 year old) I've just bought a 20mhz Hameg 203-7 analog following your video on octopus test circuits and component testing. will it complement my digital 100mhz digital scope that appears to show a lot of noise or is this noise actually real. PS shame I can only LIKE your videos once.. : ) I find I pause and or re-watch often.
You can - sort of. In the Horizontal menu of the TDS2000, you'll see you've got a menu on the side that has entries for "Main", "Window Zone" and "Window". If you select "Window Zone", you can adjust the "zoomed region" by using the SEC/DIV knob for the width and the HORIZ POSITION for the delay. Once you've got the desired area indicated by the vertical dashed cursors (using the aforementioned controls), select the "Window" menu item. The display will then show you the zoomed area. You can't get *both* the unzoomed waveform and the zoomed window at the same time.
I got a question for you If i was to increase the oscillator frequency range do u think it would increase the at least view able signals in the scope I know the crt and the amplifier have a part to play as well. But perhaps there is a little more in it maybe instead of 5mhz I could get 10 or 8 or 6 for that matter just wondering I have a 500mhz digital scope but just wondering on my old tube CRT scope if I lower the capacitance on the on horizontal oscillator say I add a extra range per say to the wafer switch just wondering?
Great video Alan. So, is it safe to say that the bandwidth is actually the highest frequency that a scope can effectively measure from zero? As always, thank you again for such great videos. They really are fantastic. N0BPS
Is $200 a reasonable price for a Tektronix 456B? the scope looks in excellent cosmetic condition don't know how it performs. It comes with all the manuals and probes also includes an audio cassette. Is there a way to test it to know that it is in good condition?Can you advice please.Thank you again for very interesting video I am learning a lot.Cheers
If it is in exceptional shape with good probes and manuals, then yes. Otherwise, it is a little pricey. Maybe negotiate down closer to $150. Quick checks - make sure both channels work with calibrator and probes, make sure you have a sweep at all horizontal settings, etc. Just run through all of the controls to be sure they do what you expect.
Great presentation! You brought up a good point which most of of us would never consider when looking for a scope/upgrade. Got any for sale? Remember I'm a cheap ham! Hi! KC2RDU/ RW
if you don't have oscilloscope,and have spectrum analyzer,one little magnetic loop will do the job finding any kind of oscillation.,even if needed ,preamp can be put on analyzer input...ha ha ha but is more expensive way.
These videos are better than gold. Going through them one by one again.
Thank you very much for replying. This leads to a follow-up question: Ok, so the BW limit can in some cases clean up the signal I see on screen if there is any noise to it. But is this "clean-up" happening pre- or post-triggering? If the high-frequency noise is causing trigger problems (triggering on the noise as well, showing "two" sine waves as lobes on screen), can BW limit help me with that?
Thank you Alan! You have great videos on this channel. I'm simply watching them from the very beginning (around 7 years ago). Thank you!
Good luck, there's a lot of them. I hope you enjoy them.
Thank you! Those videos are simply perfect!
yep good guy i don't get just yet but i'm trying.
Would a 2230 have been able to spot that oscillation? It might not have been able to fully resolve it due to the 100 mhz bandwidth but would the blurred trace be evident? I guess I need to build something similar and find out. Is that something that the choice of test leads could affect as well?
Nice video, but I think, the oscillation has started after you have connected the probe to the base of the transistor. And a little tip: dont use ceramic high capacity capacitors in low frequency circuits. The ceramic is highly non-linear this means it changes its capacity when the voltage above the capacitor changes. This leads to disturbances and additional harmonics in the circuit.
My belief is that there are two equally true statements, not just for bandwidth, but for anything in life. 1. "Buy as much (best, etc) as you can afford." 2. There is no such thing as a starter or beginner anything. Learn on the best you can afford (back to statement 1.) My first scope, a 2467B, was no more difficult to learn on than a 465, or any other. When you don't know anything there are no bad habits to bring to the table.
A 2467B is a heck of a scope to be your "first" scope! I remember buying them "new" at my first job in the mid/late 80s, and they were over $12,000 due to the special microchannel-plate CRT.
@@w2aew Gotta learn on something. I love that scope. I'll never be another you, but in the 8 or 9 months I've had it I've kicked butt in learning it, mostly from watching your videos.
Now I'm going to spend even more on my new used scope this coming hamfest. Thanks Alan! No seriously, very concise and practical, not to mention tons of fun.
If you have to make do with a low bandwidth scope, you can in some cases detect oscillation by holding your finger, a metal tool or a piece of ferrite close to the circuit. If this has any effect on a waveform or or on the supply current of an AF circuit, it is oscillating at RF.
Voulu tou mention which transistor you used and what was the voltage you applied to the circuit?
It's always handy to have a Tektronix Application Engineer posting videos! Thanks!!!
Can you use x-y mode to measure the phase shift between two signals? By rate turning per sec you can tell how much those signals differ.
Knowledge right there. Learning from the best.
Could you do a video of checking capacitors in-circuit using a scope and function gen? This would be very helpful for a lot of viewers and I don't see good video postings anywhere of this topic. thx!
Thank you for all your awesome oscilloscope videos. A question; In what kind of situation could you actually take advantage of the 20 MHz BW limit button? Why would I ever want to limit the bandwidth on purpose? Why is the button even there? I have a 100 MHz analog Tek scope and would really like to know at what point I can benefit from this function. Thanks.
10 years later. I think when you wanna filter out high freq unwanted signals above 20MHz like noise spikes and stff, u would want to turn on the 20MHz BW limit. In the video, the signal is only a few KHz of a sinusoidal signal so u wouldnt see any significant difference when turning on 20MHz.
But u prob know a lot more now than me. I m just a 3rd yr ee student hehe
Usually the higher the better cuz u never know when ur circuit picks up some weird high freq shit
Excelent video. It proofs the concept - It is always good to have more bandwidth in the scope than needed. I've bought a Tektronix 2465B a few days ago for less than $500 from eBay. Post more video about scopes, I will watch them with pleasure
Thank you
Another Interesting Video that you actually LEARN something from, And it Doesn't hurt that You're a Tektronix Application Engineer!!! Tek Scopes are my Favorite( I own a 2225) Thanks!!!
what an informative video, thank you very much for posting this, gives me more reason to replace my aging 20mhz o-scope.
That is very good to know and something most people would not even think about, thanks for posting!
hello is there any case of making circuit of Gaussian pulse or pulse pair like the DME signal distance measuring equipment?
there is almost zero second hand scopes for sale here in South India above 20Mhz.. :(
Hi Alan, thanks for your great video!
I want to buy tek2467 but also see tek2467B in the market. So which one should I choose?
Because I remember you mentioned 2467 with great CRT display, right?
anyone, did you buy it? LOL
it's the batman effect... noted by the shape of the spurious waveform.
I'm looking for a analog scope to monitor my 10 meter radio on 11 meter band. What band width scope would i need for 27mhz plus?
For monitoring the RF envelope, you don't necessarily care about having accurate amplitude measurements, so you can use a scope that has lower BW. A 20 or 25MHz scope would be fine, but a 50 or 100MHz (or greater) would be better.
So, I'm about to realise that tight stiffing circuits on breadboard is wrong idea. It's parallel lines have strong interference and can cause faulty behaviour. Especially on cheap noname boards with uncertain contacts.
And is it good practice to create virtual screening, separating different circuit junctions one from another with grounded unused lines of breadboard?
Would you know how I could increase the bandwidth of an oscilloscope? I might be buying a 15 MHz scope, and I was thinking maybe if I'd want, I could increase its bandwidth. I have the schematics (Telequipment D65), so I thought I could just look on D66 and put all parts different on the D65 and that should increase its bandwidth to 25 Mhz (D66's bandwidth). Or I could go look on some other Telequipment scope and get the parts and put on this one and increase its bandwidth. What do you think?
PS: I was also told I could be limited too by the CRT. So I guess I could increase it to for example 100 MHz and then let the CRT decide where it could take me. Good or awful idea? haha
In any case, thank you for the video!
If you compare the service manuals (schematics and PCB layouts), you can determine if they 15MHz version is intentionally BW limited down from 25 or something wider. However, keep in mind that even if you are able to convert it, it would likely need tuning/calibration to be flat over the rated BW.
@@w2aew Thank you for the fast reply. What components do you think that will need replacement if I attempt to do this? Caps, inductors and transistors? (The ones that came to my mind that rely on frequency - in the case of transistors, for the gain.)
Wow! I learned a lot thanks from an newcomer to oscilloscopes.
The high freq. oscillations are due to the bird wisle at the background.
Oh, how I'd appreciate to see how those signals appear on a 100 Mhz oscilloscope, like Tektronix 465B you've got!
Hmm, I don't have this circuit assembled anymore. I guess that the magnitude of the oscillations will appear lower due to the lower BW. I think that the delayed timebase probably won't have enough brightness to perform this much magnification on the oscillating section.
Does that circuit (as drawn) actually work? The link to base from 200k & 10nF looks wrong. I'd swap the link and the 200k about?
That's right - I used to have an annotation in the video that corrected this mistake, but TH-cam eliminated the annotation feature. The schematic is drawn properly in this video:
th-cam.com/video/IcrnXRbkLpc/w-d-xo.html
Just a noob question (all be it from a 52 year old) I've just bought a 20mhz Hameg 203-7 analog following your video on octopus test circuits and component testing. will it complement my digital 100mhz digital scope that appears to show a lot of noise or is this noise actually real.
PS shame I can only LIKE your videos once.. : ) I find I pause and or re-watch often.
Well, more bandwidth = more noise. Also, analog scopes often hide some noise due to the phosphor response.
Given that you also own a tds2000 series, is it possible to do the same delayed triggering zoom trick with a tds2000 series?
You can - sort of. In the Horizontal menu of the TDS2000, you'll see you've got a menu on the side that has entries for "Main", "Window Zone" and "Window". If you select "Window Zone", you can adjust the "zoomed region" by using the SEC/DIV knob for the width and the HORIZ POSITION for the delay. Once you've got the desired area indicated by the vertical dashed cursors (using the aforementioned controls), select the "Window" menu item. The display will then show you the zoomed area. You can't get *both* the unzoomed waveform and the zoomed window at the same time.
3:06 "I'm Batman"
Great demonstration... and nice scope;-)
I got a question for you If i was to increase the oscillator frequency range do u think it would increase the at least view able signals in the scope I know the crt and the amplifier have a part to play as well. But perhaps there is a little more in it maybe instead of 5mhz I could get 10 or 8 or 6 for that matter just wondering I have a 500mhz digital scope but just wondering on my old tube CRT scope if I lower the capacitance on the on horizontal oscillator say I add a extra range per say to the wafer switch just wondering?
Probably not. The horizontal and vertical amplifiers and CRT drivers will likely not have enough response to extend the frequency range by much.
@@w2aew Am sure your probably right am sure they squeezed every bit of bandwidth they could out as it is.
Okay Mister funnypants, now tell us seriously.. how did you draw Batman (at 3:06) on there? ;-)
Great video Alan. So, is it safe to say that the bandwidth is actually the highest frequency that a scope can effectively measure from zero?
As always, thank you again for such great videos. They really are fantastic.
N0BPS
Looks like u found my video describing scope bandwidth and you no know why the answer to this question is no.
+w2aew Indeed!
Is $200 a reasonable price for a Tektronix 456B? the scope looks in excellent cosmetic condition don't know how it performs. It comes with all the manuals and probes also includes an audio cassette. Is there a way to test it to know that it is in good condition?Can you advice please.Thank you again for very interesting video I am learning a lot.Cheers
If it is in exceptional shape with good probes and manuals, then yes. Otherwise, it is a little pricey. Maybe negotiate down closer to $150. Quick checks - make sure both channels work with calibrator and probes, make sure you have a sweep at all horizontal settings, etc. Just run through all of the controls to be sure they do what you expect.
Thank you will follow your advice.
Great presentation! You brought up a good point which most of of us would never consider when looking for a scope/upgrade. Got any for sale? Remember I'm a cheap ham! Hi! KC2RDU/ RW
if you don't have oscilloscope,and have spectrum analyzer,one little magnetic loop will do the job finding any kind of oscillation.,even if needed ,preamp can be put on analyzer input...ha ha ha but is more expensive way.
Very informative, thanks for posting this.
@w2aew My Dream scope would be the Tek 2465...300Mhz B.W. ....More Than Enough!!!
Pure Magic 🙂
very good !!!
Thank You for posting ! :) QC