Author Topic: Another scope recommendation request with a twist.  (Read 6521 times)

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Offline RossH0755Topic starter

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Another scope recommendation request with a twist.
« on: April 02, 2020, 01:50:10 am »
Hi, all.  Thank you for reading and responding to my post.  I am retired and am getting deeper into my new hobby, restoring old tube radios, which would include shortwave.  I am looking for an analog scope with 200+MHz, 1GS/s, and four channels.  "Beginner" or "starter" anything isn't part of my vocabulary (it's no harder to learn on the best you can afford) and tend to over buy the first time rather than be sorry later.  Budget?  Let's say $800.00.

Having said all that, if someone can make a good argument for DSO's for HF, I'm willing to listen.  You're the experts, not me.

Since the question seems to be asked a lot I'm in Central California.

Thanks,
Ross
 

Offline stafil

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Re: Another scope recommendation request with a twist.
« Reply #1 on: April 02, 2020, 01:55:13 am »
Having been through the same exercise myself recently, my advice is that you take into consideration if an oscilloscope can be hacked or not.

« Last Edit: April 02, 2020, 02:04:08 am by stafil »
 

Offline bob91343

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Re: Another scope recommendation request with a twist.
« Reply #2 on: April 02, 2020, 03:14:58 am »
I got my wonderful HP54542A for not much money a few years ago.  Four channels, 500 MHz and lots of functionality.  Yes it's obsolete, even uses floppy disc.  But I haven't told it that so it thinks it's the latest.
 

Offline tautech

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Re: Another scope recommendation request with a twist.
« Reply #3 on: April 02, 2020, 04:22:09 am »
Hi, all.  Thank you for reading and responding to my post.  I am retired and am getting deeper into my new hobby, restoring old tube radios, which would include shortwave.  I am looking for an analog scope with 200+MHz, 1GS/s, and four channels.  "Beginner" or "starter" anything isn't part of my vocabulary (it's no harder to learn on the best you can afford) and tend to over buy the first time rather than be sorry later.  Budget?  Let's say $800.00.

Having said all that, if someone can make a good argument for DSO's for HF, I'm willing to listen.  You're the experts, not me.

Since the question seems to be asked a lot I'm in Central California.

Thanks,
Ross
Analog scopes by definition don't do GSa/s.
That's entirely a DSO's domain and a single 1 GSa/s ADC is inadequate to meet Nyquist using 4 channels at 200 MHz.
For your disclosed requirements a DSO with good FFT could well be of use as a poor mans (please don't take offence) spectrum analyser.
At your spending level SDS1104X-E hacked or its big brother SDS1204X-E could be well worth a look.

If you want to see some FFT screenshots of frequencies you might work with please just ask.
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Offline jemangedeslolos

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Re: Another scope recommendation request with a twist.
« Reply #4 on: April 02, 2020, 12:28:12 pm »
[Mode ntcnico]

GW Instek ?

There is a youtube channel that may interest you : Kiss Analog
He made some test on scope and he is very focused on audio.
He made a review on GW Instek MDO-2204eg which combines a scope and a spectrum analyzer :

There is a promo on this one : https://eleshop.eu/gw-instek-mdo-2074eg-oscilloscope.html

I don't know if this scope is available at this price in US ?

ntnico will probably have more info to unlock BW and options on this model.

[/Mode ntnico]

 
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Offline nctnico

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Re: Another scope recommendation request with a twist.
« Reply #5 on: April 02, 2020, 02:09:46 pm »
I think I'll cancel my forum subscription... my work is done here..  :popcorn:

To add: the GW Instek GDS2074-E + hacking it with the key generator (to 300MHz on 2 channels) could be a consideration. That would also get the serial protocol decoders and the MDO functionality. OTOH the  MDO-2204eg has an internal function generator. Don't know if bode plotting is possible though but last time I checked bode plotting on these oscilloscopes was not stellar anyway.

I think the Siglent Tautech suggested is pretty much on par (the hardware is nearly identical) except that the GW Instek has individual channel controls instead of shared.
« Last Edit: April 02, 2020, 02:26:16 pm by nctnico »
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Offline AVGresponding

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Re: Another scope recommendation request with a twist.
« Reply #6 on: April 02, 2020, 02:22:46 pm »
If you're going to be poking around in old tube radios it might be worth getting some HV differential probes, to save you from letting out the magic smoke by accident too easily.
That'll have a significant impact on your budget, as they aren't cheap.
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Offline 2N3055

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Re: Another scope recommendation request with a twist.
« Reply #7 on: April 02, 2020, 02:26:28 pm »
I think I'll cancel my forum subscription... my work is done here..  :popcorn:

LOL!   :-DD
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Offline 2N3055

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Re: Another scope recommendation request with a twist.
« Reply #8 on: April 02, 2020, 02:27:44 pm »
If you're going to be poking around in old tube radios it might be worth getting some HV differential probes, to save you from letting out the magic smoke by accident too easily.
That'll have a significant impact on your budget, as they aren't cheap.


This is good advice. Micsig makes cheapest decent HiVolt Diff probes..
"Just hard work is not enough - it must be applied sensibly."
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Offline jemangedeslolos

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Re: Another scope recommendation request with a twist.
« Reply #9 on: April 02, 2020, 04:10:19 pm »
I think I'll cancel my forum subscription... my work is done here..  :popcorn:

 ;D

I figured that since Ross is retired, he may have less good eyesight and so he won't be put off by the ugliness of this scope  >:D
 

Offline stafil

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Re: Another scope recommendation request with a twist.
« Reply #10 on: April 02, 2020, 06:57:33 pm »
[Mode ntcnico]

GW Instek ?

There is a youtube channel that may interest you : Kiss Analog
He made some test on scope and he is very focused on audio.
He made a review on GW Instek MDO-2204eg which combines a scope and a spectrum analyzer

There is a promo on this one : https://eleshop.eu/gw-instek-mdo-2074eg-oscilloscope.html

I don't know if this scope is available at this price in US ?

ntnico will probably have more info to unlock BW and options on this model.

[/Mode ntnico]

Is there a hack for BW upgrade on MDO2074eg? Searching the forum couldn't find any
« Last Edit: April 02, 2020, 09:39:34 pm by stafil »
 

Offline Tom45

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Re: Another scope recommendation request with a twist.
« Reply #11 on: April 02, 2020, 08:41:06 pm »
Welcome Ross,

You asked about analog scopes and everyone is telling you about digital scopes.

For analog scopes with 4 channels and >= 200 MHz, look at the Tek 2465x series, or the Tek 7000 mainframes.

The 2465x scopes have limited capabilities for channels 3 and 4. So think carefully about whether you could live with that.

The Tek 7000 scopes are very flexible with the variety of plugins available. An example would be a 7704 or 7904 mainframe with 2 7A26 vertical plugins and 7B80 and 7B85 for the horizontal.

In both cases these are going to be used and quite old. So take some care in ensuring that you get a scope that is working.
 

Offline AVGresponding

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Re: Another scope recommendation request with a twist.
« Reply #12 on: April 02, 2020, 09:33:56 pm »
Welcome Ross,

You asked about analog scopes and everyone is telling you about digital scopes.

For analog scopes with 4 channels and >= 200 MHz, look at the Tek 2465x series, or the Tek 7000 mainframes.

The 2465x scopes have limited capabilities for channels 3 and 4. So think carefully about whether you could live with that.

The Tek 7000 scopes are very flexible with the variety of plugins available. An example would be a 7704 or 7904 mainframe with 2 7A26 vertical plugins and 7B80 and 7B85 for the horizontal.

In both cases these are going to be used and quite old. So take some care in ensuring that you get a scope that is working.

And especially in the case of the mainframe, bloody huge!

A slightly outside the box idea might be a used scopemeter. I realise these are expensive for what they are, and I don't personally know any with more than 2 channels, but they are fully isolated, removing the need for expensive differential probes (unless you're planning on probing the cathode on a CRT).
nuqDaq yuch Dapol?
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Online tggzzz

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Re: Another scope recommendation request with a twist.
« Reply #13 on: April 02, 2020, 09:38:37 pm »
Hi, all.  Thank you for reading and responding to my post.  I am retired and am getting deeper into my new hobby, restoring old tube radios, which would include shortwave.  I am looking for an analog scope with 200+MHz, 1GS/s, and four channels.  "Beginner" or "starter" anything isn't part of my vocabulary (it's no harder to learn on the best you can afford) and tend to over buy the first time rather than be sorry later.  Budget?  Let's say $800.00.

Having said all that, if someone can make a good argument for DSO's for HF, I'm willing to listen.  You're the experts, not me.

Since the question seems to be asked a lot I'm in Central California.

Thanks,
Ross

Two points you need to consider.

Firstly, what do you want to measure? You should understand the consequences that scopes' sensitivity and linearity will have on your measurements. Often radio tests are better done with frequency domain equipment like spectrum analysers plus a DMM.

Secondly the scope probe cannot be saparated from the scope. You must use the appropriate type, and some will cost as much as your scope. Some information can be found in the references at https://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline thm_w

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Re: Another scope recommendation request with a twist.
« Reply #14 on: April 02, 2020, 09:45:46 pm »
Welcome Ross,

You asked about analog scopes and everyone is telling you about digital scopes.

For analog scopes with 4 channels and >= 200 MHz, look at the Tek 2465x series, or the Tek 7000 mainframes.

He did also say 1Gs/s, which is not possible as far as I know..
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Offline bob91343

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Re: Another scope recommendation request with a twist.
« Reply #15 on: April 02, 2020, 10:00:24 pm »
My 4 channel HP 54542A claims 1 Gs/s and has 4 channels each 500 MHz.  How is that possible?  In fact I have looked at signals over 600 MHz with it.  Of course I must beware of aliasing but otherwise it seems to violate some Nyquist criterion or something.
 

Online tggzzz

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Re: Another scope recommendation request with a twist.
« Reply #16 on: April 02, 2020, 10:05:45 pm »
My 4 channel HP 54542A claims 1 Gs/s and has 4 channels each 500 MHz.  How is that possible?  In fact I have looked at signals over 600 MHz with it.  Of course I must beware of aliasing but otherwise it seems to violate some Nyquist criterion or something.

I have observed and triggered on 1.1GHz signals on my Tek 485 scope. Of course the amplitude was reduced.

My 50kS/s scope can display 2GHz signals (140ps rise time).

Extremes are possible, but not necessarily helpful nor representative.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
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Offline tautech

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Re: Another scope recommendation request with a twist.
« Reply #17 on: April 02, 2020, 10:09:30 pm »
My 4 channel HP 54542A claims 1 Gs/s and has 4 channels each 500 MHz.  How is that possible?
Because it's a CRT based DSO.
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Online tggzzz

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Re: Another scope recommendation request with a twist.
« Reply #18 on: April 02, 2020, 10:12:07 pm »
My 4 channel HP 54542A claims 1 Gs/s and has 4 channels each 500 MHz.  How is that possible?
Because it's a CRT based DSO.

Why is the display technology the key factor?

Capture and display are orthogonal concerns.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 
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Offline nctnico

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Re: Another scope recommendation request with a twist.
« Reply #19 on: April 02, 2020, 10:35:39 pm »
My 4 channel HP 54542A claims 1 Gs/s and has 4 channels each 500 MHz.  How is that possible?  In fact I have looked at signals over 600 MHz with it.  Of course I must beware of aliasing but otherwise it seems to violate some Nyquist criterion or something.
Read the manual: it has equivalent time sampling to increase the effective samplerate but this only works for repetitive signals.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Offline tautech

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Re: Another scope recommendation request with a twist.
« Reply #20 on: April 03, 2020, 07:00:04 am »
My 4 channel HP 54542A claims 1 Gs/s and has 4 channels each 500 MHz.  How is that possible?
Because it's a CRT based DSO.

Why is the display technology the key factor?

Capture and display are orthogonal concerns.
Yeah sorry, went off on a tangent.  :palm:

Gurgling HP 54542A indicates it's a 2GSa's DSO and specs claim '2 GSa/s Sample Rate on 4 channels' which seems to indicate an ADC on each channel so Nyquist is comfortably met for 500 MHz.
https://www.keysight.com/en/pd-1000001425%3Aepsg%3Apro-pn-54542A/4-channel-2-gsa-s-digitizing-oscilloscope-obsolete?cc=NZ&lc=eng
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Offline Electro Detective

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Re: Another scope recommendation request with a twist.
« Reply #21 on: April 03, 2020, 08:14:22 am »

Guys please  :o  OP specified  "...restoring old tube radios..." 

perhaps some discussion on SAFETY and isolation techniques/gadgets may be appropriate too
so OP does not BBQ any old tube radio/s, CRT or DSO oscilloscope, and him/herself  :scared:
before they can type up a second post here..

fwiw during this C palmdemic we need ALL newb members ALIVE and kicking
to replace the millions of  'C' departed members  so far  :'(
 

Offline Fungus

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Re: Another scope recommendation request with a twist.
« Reply #22 on: April 03, 2020, 08:26:20 am »
Welcome Ross,

You asked about analog scopes and everyone is telling you about digital scopes.

That's because he asked for "a good argument for DSO's", and, let's face it, DSOs are better than CROs in just about every way possible.

(every way except looking cool)
 

Offline nctnico

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Re: Another scope recommendation request with a twist.
« Reply #23 on: April 03, 2020, 08:46:31 am »

Guys please  :o  OP specified  "...restoring old tube radios..." 

perhaps some discussion on SAFETY and isolation techniques/gadgets may be appropriate too
so OP does not BBQ any old tube radio/s, CRT or DSO oscilloscope, and him/herself  :scared:
before they can type up a second post here..
That already got answered: a differential probe. The ones from MicSig are good and very affordable. Unless if the OP has a formal training and a special work place, isolation transformers are a no-go.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Electro Detective

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Re: Another scope recommendation request with a twist.
« Reply #24 on: April 03, 2020, 08:52:39 am »
Welcome Ross,

You asked about analog scopes and everyone is telling you about digital scopes.


That's because he asked for "a good argument for DSO's", and, let's face it, DSOs are better than CROs in just about every way possible.

(every way except looking cool)



DSOs still at the starting gate compared to CRTs, on real world troubleshoots below 100mhz

Job done with CRT and DUT returned to customer  :-+ before DSO finishes booting and or scrolling through Menu options
and praying the programmed or shared channel Trigger isn't asleep on the job    :=\

 :D

 


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