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Rigol DG1022Z or Siglent sdg1032x
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bd139:
Bode plot is neat but unnecessary. You only need to work out phase flips and 3dB / 6dB points mostly and you can do that sweeping by hand effectively. Actually takes less time than setting up a bode plot and you only need a 2 chan scope for it. NanoVNA is better past 5Mhz
2N3055:

--- Quote from: bd139 on June 12, 2022, 05:44:10 am ---Bode plot is neat but unnecessary. You only need to work out phase flips and 3dB / 6dB points mostly and you can do that sweeping by hand effectively. Actually takes less time than setting up a bode plot and you only need a 2 chan scope for it. NanoVNA is better past 5Mhz

--- End quote ---

Operating word, mostly, that is if you only doing if for the stability reasons as a quick check... Than you can do it by hand. Agree.
If you want to get gain/phase response diagram doing it by hand is not really fun..
Especially if you're tweaking something that has multiple poles in response. And repeating measurements...
VNAs are usually only for 50Ω systems.
Truth is it really depends what you do. I use FRA (Frequency Response Analyser, that creates gain/phase plot) more than VNA.
The idea is that FRA is for non 50Ω systems and less than 10MHz systems...
Does somebody need that,  it is up to them, defined by what they do...

DG811 can be "unlocked" to DG992 but amplitude won't be calibrated above certain frequencies..
One thing that is great about my SDG6000X is that has VERY accurate level in full frequency range (even those "liberated", they calibrate them all full range, despite destination model speed). One thing to have in mind.
tautech:
Yeah once you've used a decent FRA application who would want to do it the old way ?

rf-loop:

--- Quote from: bd139 on June 12, 2022, 05:44:10 am ---Bode plot is neat but unnecessary. You only need to work out phase flips and 3dB / 6dB points mostly and you can do that sweeping by hand effectively. Actually takes less time than setting up a bode plot and you only need a 2 chan scope for it. NanoVNA is better past 5Mhz

--- End quote ---

Yep. you can try. Example this.


(and full dynamic range is not used even close)


Or just this very simple where -3dB bw is what it is but -60dBc points are very important (but my example is poor for this). Of course for these things are better tools but, also today these modern osccilloscopes give more and more...
(I do not have my old Rocwell-Collis filters or Racal filters BodePlots (made with other instruments) available (all gone when bunch of hard disks accidentally damaged time ago. These oscilloscopes can not go to -120dBc when ref level is 0dBm.  But, for many hobby grade things with these scopes can do lot. Lot of more than these old simple methods can even dream)


Or just simple 3 channel FRA
Again much more is is interesting than just -3dB points.




In all cases just SDG1032X used for test signal.
bd139:
That is indeed neat :)

You can have some fun with even older equipment…



log-log plot on a TDS210.

Point is it is neat indeed but it depends on the application. 90% of what is bought is unused.
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