Oscilloscope Purchase

I'm considering purchasing an oscilloscope, and have no idea what to do.

Intended Use:
I'm constructing a ham radio transceiver kit for the 80m and 40m bands (3.5-4.0, and 7.0-7.3 Mhz). I want to use the scope for trouble-shooting and alignment of the radio. I will probably construct a linear amplifier to be used at the same frequencies. Might also try a 20m radio (14.0 Mhz)


Intended User:
No experience with a scope. I've decided that I should probably avoid buying used, as I don't want to spend my time trying to determine if the problem is the circuit or the scope. Also, I want to work on radios, not repair scopes.


What I Think I Know:
The scope market has moved primarily to digital. My research, indicates that the key digital specifications are sample rate, memory, and resolution. From what I've read, radio (analog signals) will require high resolution if you want an accurate representation of the signal. Unfortunately, scopes with 12, 14, or 16 bit resolution are high dollar. This is leading me to believe that for my intended use, analog may be the way to go. Either way, I think that 100Mhz would be adequate.


The Questions:
Should I buy analog or digital?
What are the minimum specifications that I will need for the intended use?
If digital, what combination of sample rate, memory, and resolution do I need?

I really have no idea what I'm doing. It's difficult enough just trying to understand the radio theory, let alone trying to become a scope expert. I hope there is someone experienced with my intended use, that can suggest the appropriate scope and specifications.

Thanks,
John

I'm glad to hear there are people who are building thier own sets. I'm not a ham, but I really don't think digital is needed for that kind of work. A couple years ago, I ordered an analog B&K precision 2120B scope with 30MHZ bandwidth, which has been great for hobby and experimentaion. I also have a old 100mhz TEK that Ive resurrected. I've never required digital features out side of my job.

PS: If I thought I absolutely needed a digital scope, I'd consider one of the lower cost USB scope module options.

I would get a used 100-400MHz Analog Scope, TeK or HP.

I agree with mike.

Both brands of scopes are made by companies that put a lot of work into making sure they last.

I recently purchased an older used 100 MHz Fluke PM3380B CombiScope; its a digital scope, but it can also be switched into an analog mode (it uses a CRT for traces). Earlier this year I bought a Tek 2213 60 MHz analog scope. For your interests and work, I would definitely look into an analog scope, and if you can get something like my Fluke scope, that might come in handy for certain situations (I can see it being handy for tuning RF circuits, perhaps). The thing about having a pure analog mode in addition to the digital mode is the ability to bypass the ADC/DAC stages of a digital-only scope (increasing the resolution for those analog signals that require it). You might consider purchasing both a cheaper, lower-speed analog scope, and a separate reasonably priced digital scope.

You are right, though, not to buy a scope used without being experienced in using one. When buying used you definitely always want to check the scope out first-hand, and make sure it works as intended. If you do have a place that sells used scopes nearby, or you find someone selling a scope, you might enlist the help of a knowledgeable friend if you have one.

Finally, for learning how to use a scope, you might find out if there are any community colleges in your area offering electronics courses and test equipment training. You might also look into talking with any vocational tech schools in your area (do you have a local DeVry, ITT Tech, or similar school nearby?) for some training (maybe you can get an instructor or a student at such a school to show you the basics for a little cash?). If both of those don't work, though, here are a few links that might help you:

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Key tips for using an oscilloscope :: Radio-Electronics.Com
Oscilloscope Tutorial - Learn All about Oscilloscope - Electronic Circuits & Tutorials Resource
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OscilloScope Tutorial

Good luck!