why do they still make analog oscilloscopes

[turbo!]

They still make high-end Tektronix 2465 cotemporaries as well.
The Iwatsu SS-7847, 470MHz analog scope. A steal at only $17k
http://www.tequipment.net/IwatsuSS-7847A.html?v=7402

Analog and digital each have their advantage. What you posted isn't a surprise at all. Digital equipment are much cheaper with hard goods than analog counter part.

With a purchase of a set of encyclopedia, you're clearly paying a good amount for the intellectual property. A set of encyclopedias on high quality paper in full color costs thousands of times more than pressing a few DVDs. Physically, the DVD needs to be built to close enough tolerance to ensure readability and perform within acceptable vibration levels, but overwhelming portion of the cost goes to the contents. For instruments, a good portion of list price goes to dealer network as these instruments are sold through traditional business-to-business sales rep network who does everything including hand holding for end users. 

There are some parts that still require very close tolerance to actually work and can't be BS'd much, but for the most part, digital instruments can get away with roughening it in and BSing it using calibration constants. The materials used still need to be very stable in long term and critical components must have very low temperature coefficients, or have a very predictable coefficient.

A high accuracy glass thermometer requires a very accurate bore diameter to maintain linearity. A cheap one would be marked at low, and high and marked evenly through out, but if the material is the same, then it is just as precise. 5C reading might mean 4.5C and 10C might mean 10.2C, but it is consistent.  Inscribing the glass with lines where each line must corresponds to a very high level of accuracy is a costly process.  If it was to use a scanner array like optical device to read the incision where the mercury is, it can be BSed numerically by simply comparing to a reference thermometer.  So, reference thermometer and this thermometer is heated and cooled side by side until they both stabilize. If reference reads 28.0C, it marks that pixel location as 28.0C.

You don't adjust the circuit. The digital processing reports the pixel location of where the mercury was seen and this pixel location is translated into value by multiplying it with a calibration constant.

In analog circuits, proper true gain adjustments is important so that symmetric AC do not look asymmetrical.

In analog driven digital meters, the analog circuits are adjusted to reflect proper reading on the digital display. In digital setup, you don't do anything with the circuit, but use calibration constants in EEPROM to absorb the slop.

 An analog scope literally have dozens and dozens of potentiometers and take many hours to adjust. However, with a service manual and sources, you can do it.

A digital scope and automated calibration equipment talk to each other under the direction of program and quickly bust through the calibration routine. The ability to access almost every function available on front panel through the interface without touching the switch is more important for automatic production. If you need to service it later on, the constants in EEPROM are not self explanatory and you can't do anything about it and you're at the mercy of the manufacturer.

[electronics man]

However I have seen new analog oscilloscopes for under £200 - significantly cheaper than digital ones 

[madshaman]

Since this is such a hot topic, I'm curious, how many of you would purchase an analog scope as good or near as good as a Tek 2465 if it were available new for the same price points as say Rigol's equipment at the same bandwidth?

[T3sl4co1l]

Last scope I got was a DSO, but mainly because I didn't have one already; next scope, I'll probably get something higher bandwidth, which probably won't be analog.  After that... I would definitely consider a 2465 or something like that.  If I didn't already have a 475, I think it would be a higher priority.

Tim

[G0HZU]

Since this is such a hot topic, I'm curious, how many of you would purchase an analog scope as good or near as good as a Tek 2465 if it were available new for the same price points as say Rigol's equipment at the same bandwidth?

Even though I do RF design for a living up to many GHz I'm not sure I can justify the need for an analogue scope with 400MHz BW. Most of the time (i.e. pretty much always) the added BW over 100MHz would be a source of irritation because of the higher noise. However, If someone produced an analogue scope that had 100MHz/20MHz switchable BW and it was small, light, efficient and didn't produce any fan noise and it was as nice to use as my old Tek 465 then I'd be interested in buying it to replace the 465. This is because the ideal analogue scope (for me) would be small, light and efficient and easy to move around. But I think that such a scope doesn't exist even 40+ years after the 465 was launched?

[David Hess]

Besides the bandwidth advantage, higher bandwidth analog oscilloscopes also generally have a brighter and sharper CRT image giving them an advantage at low repetition rates even if you do not need the bandwidth.

[T3sl4co1l]

Every scope I've seen has a BW switch.  Do they make 400MHz+ analog scopes without this?  Why?

[David Hess]

Every scope I've seen has a BW switch.  Do they make 400MHz+ analog scopes without this?  Why?

The Tektronix mainframe style oscilloscopes only had bandwidth limits on some of their plug-in amplifiers and none of them above 200 MHz.  Oddly enough the common 100 MHz amplifier plug-ins lacked a bandwidth limit as well making the 200 MHz ones more useful even in a slower mainframe.

[madshaman]

I need a 20Mhz BW switch just to keep the local radio station off my traces and making them fat (when we move, there's going to be cheesy RF shielding, it'll be my own version of a tinfoil hat ^^).

I'm thinking chicken-wire stretched in a web over the walls and ceiling in a double layer with a space between, all held at ground.

[David Hess]

I have the same problem with ambient EMI.  The solution always ends up being better probes with shorter grounds or no probes at all.

[madshaman]

If I put the DUT inside an enclosure, I don't have a problem, the RF doesn't come through the probes.

I second that at really high frequencies, lead length outside a transmission line doesn't help, because of the sudden change of impedance and obviously the uncompensated inductance.  At least that's how I look at it.  Being self taught, I'm not always sure if I've learned to look at things the same way or the correct way..

[T3sl4co1l]

Every scope I've seen has a BW switch.  Do they make 400MHz+ analog scopes without this?  Why?

The Tektronix mainframe style oscilloscopes only had bandwidth limits on some of their plug-in amplifiers and none of them above 200 MHz.  Oddly enough the common 100 MHz amplifier plug-ins lacked a bandwidth limit as well making the 200 MHz ones more useful even in a slower mainframe.

Well obviously, it still has a switch, it's just a lot bigger than most yank this, shove that...

Tim

[electronics man]

Every scope I've seen has a BW switch.  Do they make 400MHz+ analog scopes without this?  Why?

The Tektronix mainframe style oscilloscopes only had bandwidth limits on some of their plug-in amplifiers and none of them above 200 MHz.  Oddly enough the common 100 MHz amplifier plug-ins lacked a bandwidth limit as well making the 200 MHz ones more useful even in a slower mainframe.

Well obviously, it still has a switch, it's just a lot bigger than most yank this, shove that...

Tim

Not tektronix but still interesting

[electronics man]

the only reason i would buy an analog oscilloscope is for xy mode

[madshaman]

the only reason i would buy an analog oscilloscope is for xy mode

There are plenty digital scopes with XY mode.

[electronics man]

the only reason i would buy an analog oscilloscope is for xy mode

There are plenty digital scopes with XY mode.

I know, nearly all of them but they are not as good for xy mode as analog ones are

[David Hess]

All of the DSOs I have seen operated in XY mode had pretty poor displays if only because of the way the record length interacts with the acquisition rate.  A long record length is needed for a continuous display but that same long record length limits the acquisition rate making the display update slowly.  Ideally the record length could be adjusted to be synchronous with the input signals but that defeats any easy use of XY mode and not all input signal are synchronous.

One advantage DSOs do have though with XY displays is high X bandwidth.  In an analog oscilloscope operating in XY mode, the vertical delay line introduces a phase error at low frequencies limiting performance to 10s of kHz.  If that is compensated for which was a common option, then the relatively low horizontal bandwidth still limited performance to about 1 MHz.  There were some expensive exceptions but the fastest I know of worked to 50 MHz.

[David Hess]

the only reason i would buy an analog oscilloscope is for xy mode

I bought an analog storage oscilloscope simply because it was a lot less expensive than the 4 channel 400 MHz DSO that could match its specifications.  Then I bought two old DSOs for the same reason instead of a single modern 4 channel DSO.  Between all of them I have more channels and more bandwidth at less cost than even a low end Rigol although I dismissed Rigol because of their misleading marketing.

I acknowledge that that is not an avenue available to most people since they lack the experience to know what they need and the ability to maintain an old test instrument.  It is pretty easy to be seduced by DSO features which are actually unimportant.

[w2aew]

Analog scopes are still the best for monitoring RF transmitter output in applications like this:

[Dave Turner]

Whilst rebuilding my lab after an absence of decades I've been severely limited by available space and budget. After discussion in this forum I chose a Rigol DS1074-Z which covers my needs.

However had I more space and funds I would no doubt purchase an analogue scope.

In whatever field one works in one should always learn the limitations of the tools at one's disposal and use the most appropriate for the job at hand. Even more important is to understand why and how they are used.

Whilst useful &^%$£ auto can be counterproductive; use your head. It is, or should be, the most important instrument.

[madshaman]

Whilst rebuilding my lab after an absence of decades I've been severely limited by available space and budget. After discussion in this forum I chose a Rigol DS1074-Z which covers my needs.

However had I more space and funds I would no doubt purchase an analogue scope.

In whatever field one works in one should always learn the limitations of the tools at one's disposal and use the most appropriate for the job at hand. Even more important is to understand why and how they are used.

Whilst useful &^%$£ auto can be counterproductive; use your head. It is, or should be, the most important instrument.

+1

Totally agree, in ANY field:

Know your tools, know them well.

Use the right tool for the right job.

Don't have the right tool?  Make it or buy it.

It's so fundamental.

[electronics man]

But with limited funds a DSO gives you more bang for your buck

[David Hess]

But with limited funds a DSO gives you more bang for your buck

If used instruments are included then I disagree; a majority of applications do not require digital storage and some are better suited to an analog oscilloscope because of features they have which modern DSOs lack like dual sweep or continuous X-Y display.  It is also possible to get more bandwidth for a given cost in the used analog oscilloscope market.

[electronics man]

But with limited funds a DSO gives you more bang for your buck

If used instruments are included then I disagree; a majority of applications do not require digital storage and some are better suited to an analog oscilloscope because of features they have which modern DSOs lack like dual sweep or continuous X-Y display.  It is also possible to get more bandwidth for a given cost in the used analog oscilloscope market.

I disagree most of the time I find my self stoping capture and looking at the data in the capture memory and you can't do that on a regular analog oscilloscope.

[Lukas]

But with limited funds a DSO gives you more bang for your buck

I obtained a 400MHz analog storage Tektronix 7834 Oscilloscope for <100€ at a local hamfest. It also came with a 7A22 (10µV/div, 1MHz) plugin. No DSO comes even close.