Looking at a HP54501A...

[ruku]

Hey all, I'm looking at scopes again. Drooling, dreaming, and hoping.

Right now I've found a decent deal on an in-shape HP54501A. I'm interested to see if anyone has any experience with these, and what they think about it. I know I found someone with an 02A, which is the 400 MHz model. I'm not entirely sure I want to buy just a 100 MHz scope, since I'd like to try doing some 2 meter amateur radio circuits.

For $225 as a first scope, what do you all think? Would you be content with an 8-bit A/D or would you want something else? Anyone have nightmare stories about the scope falling to pieces?

[alm]

I'm not entirely sure I want to buy just a 100 MHz scope, since I'd like to try doing some 2 meter amateur radio circuits.

Why would you want to use a scope to look at a modulated signal? This is usually fairly useless, other test equipment like spectrum analyzers and power meters are used for this.

For $225 as a first scope, what do you all think? Would you be content with an 8-bit A/D or would you want something else?

I'm not familiar with the scope and its vintage. How's the real time sampling rate? Memory depth? If it's an early DSO, the controls and responsiveness may not be great. 8-bit is standard, nothing wrong with that for a scope. Most don't get anywhere close to 8 effective bits anyway at higher frequencies. A scope is not a precision instrument with a large dynamic range.

[vtl]

$225 is quite steep I think. This is an early digitizing scope with only 10M/S which is kind of limiting. You'd be probably limited to about 1MHz signals in single shot mode. Maybe you could consider the Rigol ds1052e which is quite popular here.

[saturation]

For 2 meter band hams, I presume you need  ~ 150 MHz accurately, alas that HP is outdated, as others have described, mostly particularly its low sampling rate. 

http://www.home.agilent.com/upload/cmc_upload/All/hp54501a.ih?&cc=US&lc=eng

If you really need 150 MHz, you're only bet at that price range is a good used analog scope, or you'll have to move up to at minimum, at 3x your price range, a Rigol style DSO in the 100 MHz range,  or in the $400 range, risk hacking a 1052e to 150 MHz.

[EEVblog]

$225 is quite steep I think. This is an early digitizing scope with only 10M/S which is kind of limiting.

I'd go one step further and say it's pretty much useless as a single shot scope. In which case an equivalent bandwidth analog would be a better option.
But getting one for that price might be rather hard.

Dave.

[EEVblog]

Here is a nice Tek 2465A, a superb analog scope, $350MHz for $400
eBay auction: #150626077856

or a 250Mhz Tek 475A for $270:
eBay auction: #260813412483

A nice 200MHz Philips Combiscope for $400:
eBay auction: #330581792710


Dave.

[ruku]

$225 is quite steep I think. This is an early digitizing scope with only 10M/S which is kind of limiting.

I'd go one step further and say it's pretty much useless as a single shot scope. In which case an equivalent bandwidth analog would be a better option.
But getting one for that price might be rather hard.

Dave.

Vtl and dave, That's exactly what I was worried about... 8 bit @ 10 Msps seemed a little limiting, I just had no idea what to expect.

Vtl you were right about it being 1 MHz in single shot. What exactly does that mean?

I've (ironically) seen a 2465B for a good price... I think I'm gonna track that guy down and see if its still for sale.

[ruku]

Why would you want to use a scope to look at a modulated signal? This is usually fairly useless, other test equipment like spectrum analyzers and power meters are used for this.

I'm not familiar with the scope and its vintage. How's the real time sampling rate? Memory depth? If it's an early DSO, the controls and responsiveness may not be great. 8-bit is standard, nothing wrong with that for a scope. Most don't get anywhere close to 8 effective bits anyway at higher frequencies. A scope is not a precision instrument with a large dynamic range.

The memory depth has 501 samples. I'm guessing that's bad.

And while spectrum analyzers and power meters would be nice... but I need a decent scope too You have a point.

[gregariz]

Why would you want to use a scope to look at a modulated signal? This is usually fairly useless, other test equipment like spectrum analyzers and power meters are used for this.

I'm not familiar with the scope and its vintage. How's the real time sampling rate? Memory depth? If it's an early DSO, the controls and responsiveness may not be great. 8-bit is standard, nothing wrong with that for a scope. Most don't get anywhere close to 8 effective bits anyway at higher frequencies. A scope is not a precision instrument with a large dynamic range.

The memory depth has 501 samples. I'm guessing that's bad.

And while spectrum analyzers and power meters would be nice... but I need a decent scope too You have a point.

A scope will be just fine to adjust AM/SSB modulation. A deviation meter for FM. Other digital/analog modes will generally need a purpose built test set.

[vtl]

$225 is quite steep I think. This is an early digitizing scope with only 10M/S which is kind of limiting.

I'd go one step further and say it's pretty much useless as a single shot scope. In which case an equivalent bandwidth analog would be a better option.
But getting one for that price might be rather hard.

Dave.

Vtl and dave, That's exactly what I was worried about... 8 bit @ 10 Msps seemed a little limiting, I just had no idea what to expect.

Vtl you were right about it being 1 MHz in single shot. What exactly does that mean?

I've (ironically) seen a 2465B for a good price... I think I'm gonna track that guy down and see if its still for sale.

Dave's gone over it in the beginner's oscilloscope video, highly recommened. When you use an oscilloscope you often want to look at signals that are not periodic, I mean, if all your signals are perfect and periodic you probably didn't need to look at it with an oscilloscope.

So you want to capture a single burst and look at the data and in this mode the scope will take a number of samples which for this scope is 10M/S. Now to look at the signal properly you'll ideally want minimum of 10 or more samples per period of the signal youre trying to capture. So for this scope 10M/10 = 1MHz. Lets not forget the sample memory because these samples are stored. This scope was manufactured in an era where memory was expensive so your capture won't cover much either.

[Frangible]

That's not a bad scope for digital debugging work.  I used one for a while in the early 90s - long before today's crop of wonder-scopes were available.  One thing about these scopes is that they do not have a high sample rate, so they will very often display a bogus signal if what they are measuring is above Nyquist.  For $225 I would expect to also receive a student-grade analog scope of the same vintage in the package, as you will certainly need it to back up that one.