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eHam Forums => Elmers => Topic started by: KC2ZPK on February 27, 2012, 02:44:48 PM



Title: Decent first scope?
Post by: KC2ZPK on February 27, 2012, 02:44:48 PM
I am looking for a decent oscilloscope. What is a decent first scope that I can get used and not break the bank? Also what features should I look for, and why?

Thanks


Title: RE: Decent first scope?
Post by: WB2WIK on February 27, 2012, 03:01:28 PM
I'd say it depends entirely on what you'll be using it for.


Title: RE: Decent first scope?
Post by: KH6AQ on February 27, 2012, 03:20:33 PM
The OWON digital oscilloscopes look very attractive for the money. I tried one out five years ago and it wasn't bad.

The PDS5022S is a dual channel 25 MHz digital for $250 at AMAZON.COM. It has an 8" color LCD display.

OWON also makes 60 and 100 MHz 'scopes and they all look to be copies of Tektronix.





Title: RE: Decent first scope?
Post by: KK4GER on February 27, 2012, 03:40:37 PM
Basically, the higher the vertical bandwidth (40, 60, 100, 200 MHz, etc.) the more accurately it will reproduce the incoming signal.  Assuming you are looking at HF radio "stuff," a 100 MHz, dual trace, dual timebase, delayed sweep, would be a place to start, if looking at an analog 'scope.  If digital, the bandwidth still applies, but the digital scopes usually have "windowing" for expanding a portion of the signal, in lieu of the dual timebase, delayed sweep.  The 100 MHz is not essential; I have a 40 MHz analog and a 60 MHz digital which I have used for years, but you have to realize there limitations.  There were a couple of older Tektronix scopes for sale in the classified section (may still be there) with 100 MHZ bandwidths, for a couple hundred dollars, which if working as described, would be a good value.  Hope this helps.


Title: RE: Decent first scope?
Post by: W2AEW on February 27, 2012, 07:00:07 PM
If part of your use is going to be looking at the envelope of modulated RF signals, then there aren't many DSOs that can do this better than an old analog CRT-based oscilloscope.  You can typically find a decent analog scope for $100 or less.  The older Tektronix models like the 465B, 2215, etc. are very good performers and very reliable.  Nearly any of the 400, 2200 or 2400 series in operating condition would be good ones.


Title: RE: Decent first scope?
Post by: KC2ZPK on February 27, 2012, 07:27:55 PM
If part of your use is going to be looking at the envelope of modulated RF signals, then there aren't many DSOs that can do this better than an old analog CRT-based oscilloscope.  You can typically find a decent analog scope for $100 or less.  The older Tektronix models like the 465B, 2215, etc. are very good performers and very reliable.  Nearly any of the 400, 2200 or 2400 series in operating condition would be good ones.

Yes one of the goals is to watch the modulated RF, as well as some basic repair, alignments


Title: RE: Decent first scope?
Post by: W2AEW on February 27, 2012, 07:31:55 PM
If part of your use is going to be looking at the envelope of modulated RF signals, then there aren't many DSOs that can do this better than an old analog CRT-based oscilloscope.  You can typically find a decent analog scope for $100 or less.  The older Tektronix models like the 465B, 2215, etc. are very good performers and very reliable.  Nearly any of the 400, 2200 or 2400 series in operating condition would be good ones.

Yes one of the goals is to watch the modulated RF, as well as some basic repair, alignments

You may want to look at this video of mine.  Most digital scopes would have difficulty replicating these displays:
http://www.youtube.com/watch?v=y4Zt_LJX1Tc (http://www.youtube.com/watch?v=y4Zt_LJX1Tc)


Title: RE: Decent first scope?
Post by: K7MH on February 27, 2012, 11:38:24 PM
Tektronix 465B.
You may even find one with the DM44.
Watch Craigslist for one. There are almost always a few on Craigslist around here and that is where I found mine with the DM44 and 3 probes for $100.


Title: RE: Decent first scope?
Post by: AD4U on February 28, 2012, 07:24:54 AM
Used Tektronics or used HP scopes - 100MHz or greater and dual trace.  These can be found at hamfests in good condition for around $100 - $150.  Most go un-purchased because so many HAMs do not know what to do with them.

After a good VOM, a good scope is the best investment in test gear.

Dick  AD4U


Title: RE: Decent first scope?
Post by: KC2ZPK on February 28, 2012, 09:49:19 AM
Thanks for the suggestions!


Title: RE: Decent first scope?
Post by: KC2ZPK on December 03, 2012, 05:47:11 AM
OK, going to revive this a little.

Is there a need for 4 channels?

I have since gotten the bug for 2M/440MHz as well, and would 100MHz be enough?


Title: RE: Decent first scope?
Post by: AC7ZN on December 04, 2012, 05:39:40 AM
Hi John,

Two channels are essential as we often must compare relative phases or timing of two signals.  Having four channels is more of a convenience, especially for troubleshooting digital circuits.  Multiple measurements on two channels can often compensate for the lack of four channels. 

A 100 MHz scope will probably show something at 2 meters but will not be accurate in amplitude.  It is doubtful you will get anything useful at 440 MHz.  Because price really jumps for scopes faster than 100 MHz, you might consider using a mixer and signal generator to mix 440 MHz signals down to a frequency the scope can see.  This is not adequate for all measurements but can tell you if you have a signal, and what frequency and amplitude it is (assuming you have an accurate signal generator and have characterized the mixer loss).

I happen to be a fan of digital scopes as they can capture single events and most have FFT capabilities built in, but these are features for an experimenter and you may be more comfortable with an analog scope (fewer 'gotchas').

73,
Glenn AC7ZN


Title: RE: Decent first scope?
Post by: N3QE on December 04, 2012, 07:20:33 AM
I am looking for a decent oscilloscope. What is a decent first scope that I can get used and not break the bank? Also what features should I look for, and why?

$5-$10 at a hamfest will fetch you a mostly working crufty old Eico or Heathkit scope good enough to look at waveforms up to a few MHz. Sometimes for that price you can get a slightly more modern "TV serviceman" or "high school electronics class" quality scope.

The way to judge if it is "mostly working" is to stick your finger on the input and make sure it shows hum and other fuzz, and to make sure with no input there's not much fuzz on the trace. Pretty likely that some knobs and switches will have settings that don't work, as long as there's some setting that lets you see a waveform, that's a good start.

There will be almost no quantitative ability to judge times or voltages more accurately than 50% but the vast majority of scope use is not to measure "is the voltage right to a fraction of a volt". The vast majority will be "is there a waveform that looks right with about the right frequency at this point in the circuit". The cheap scope will also let you "tune for maximum amplitude" (aka "tune for maximum smoke" if you don't have a scope!) under many circumstances.

A Tek 455 or similar will get you to the next step up, with substantial quantitative ability (assuming good calibration, as good as a couple percent) and 100 MHz bandwidth but will cost you a lot more.

Tim.


Title: RE: Decent first scope?
Post by: N0SOY on December 09, 2012, 10:20:51 AM
I had good luck with the Owon Digital scopes.  4 years ago 4 of them were purchased for the lab that the students used.  They always get hard use.  They are working fine.  In the past we used Leader and tectronix but they have over priced themselves.  When I purchased the Owons they cost $300 each while the Tectronix cost over $1200 for the same specs. 

Also there are some compact analog scopes put out by Madell that are nice.  I have one and it works fine.  It is a small analog 10 mhz single channel with a crt.  It cost about $130 about 3 years ago. 
It would be a good one to learn to use as scope with. 



Title: RE: Decent first scope?
Post by: K2OWK on December 09, 2012, 02:10:54 PM
 Scopes are specked at 3 db per octave. A 100 MHz scope will be 3 db down at 100 MHz. Not very useful at 2m/70cm. If you need to look at these frequencies a sampling scope would work. An older Tektronix scope (the Rolls Royce of oscilloscopes) are available for reasonable prices used. I have a Tektronix 2215A 60 MHZ duel channel scope I paid $130.00 for.

73s

K2OWK