Here we are again, yet another "which oscilloscope" thread, but as you might guessed my requirements are different than that of others'...
So, I have a strange obsession with high bandwidth analog video signals (like VGA) with pixel clock beyond standard 1080P. An oscilloscope with 300+ MHz bandwidth is desired for these applications.
For several years now my trusty companion is a HP 1720A oscilloscope, this is the base model of HP's fastest analog oscilloscope range, having 275MHz bandwidth (on paper at least), at that time this was the only scope for the purpose that I could afford. Over the years I gathered several 250MHz passive probes for it, and also got a HP 1120A 500MHz FET probe with all the dividers (which I intend to keep with any future oscilloscopes) .
When doing measurements I either use direct probing ie. having the oscilloscope as the load for the circuit of interest, or for in circuit measurement I mostly use the FET probe. If I am not measuring the video stuff, then I am doing some audio trouble shooting and other not too demanding hobby projects.
The thing is this oscilloscope was manufactured in 1977, so turning 42 this year (10 years older than me). While I don't have particular plan to ditch it, but I also can't expect to last for ever. Furthermore, as it seems it does not live up to its specs as far as bandwidth goes, since I hardly could measure rise times below 1.5ns while my pulse generator's rise time is confirmed to be 425ps with a 2.5GHz LeCroy scope. Nevertheless I can use this scope for the purpose still. The best thing I like about it is that it is completely silent, as there is no fan inside. This is important, because my workbench is located in our living room (small apartment)
The idea is not new for me to look for a new oscilloscope, in fact I've had some, but none of them stayed for too long, here is the list:
-Yokogawa DL1740: 4CH 500MHz scope with 500MS/s sampling on all channels or 1GS/s on two or less channels (20GS/s in ETS), 1MS memory. I got it as faulty (bad input preamp chip), but managed to fix it, although a few days later an other input preamp chip blew up for no reason, got it fixed, but this raised the red flag to not hold on to this scope for too long, Sold it locally with 3 more spare input chips -just in case... Functionally it was a nice scope, but had an odd cubature not fitting well in to my bench, also had a loud fan, and the bad reliabilty...
-HP 54503A: 4CH 500MHz scope, with 20MS/s sampling. This was advertised as a dead unit, but was so cheap I could not resist, and bought it for curiosity. Eventually got this fixed as well, and my general impression on this unit was generally very positive, but the low capture rate (especially with vectors or measurements on) made me sell this unit as well, oh and this one also had a loud fan.
-Currently I am playing with a GaGe CompuScope 82G scope card, what got me in this is the 2GS/s sample rate (one channel), and reasonable memory depth at 2MS. This is a nice one, and is a great supplement for the HP 1720A (some things being better, some things worse). But now I also have this for sale, although I won't be sad if there will be no taker for it, although as I've found out I'd prefer an all in one solution instead.
I was thinking about getting into the Tek 2465 line or a 485, but if I am honest these aren't a real step towards the future.
So is there any scope you can recommend that has:
- 2-4 Channels (no logic functionality required)
- Is "digital" with reasonable capture rate and possibility to extract data, etc.
- Having 300-500Mhz bandwith on repetitive signals, and single shot bandwidth of >150MHz
- reasonably quiet operation
- Can be aquired for cheap on used market (<500€)