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How do the features in old VNAs and SAs differ from new ones?
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ballsystemlord:

--- Quote from: rsjsouza on March 09, 2024, 03:07:58 am ---<snip>
I will focus on the wireless device and not necessarily on the oscilloscope.
<snip>

--- End quote ---
The alluded to device would probably make me money more quickly and easily than the scope. But whenever I see electronic equipment, I start to think of how it could be better. You know the TEA thread? That's what I am but in reverse. I have fantasies about hand solding prototype high-end electronics. It doesn't matter if it's an oscilloscope or a calculator, I still want to make one and make it better. Maybe I should seek professional help. Hey, any EEs want to give me a hand? -- Well I did say professional, never mentioned psychiatrist. ;)
ballsystemlord:
Several people so far have pointed out the lack of being able to take screen shots using USB as a bit of missing functionality. I'd like to point out that USB screen shots tend to be a tacked on feature and they don't even necessarily work. Please note that I'm not trying to rant against any of you. I'm pointing out that this really is not a big deal because of how borked it is, at least in my experience.

For example, you have modern equipment that can only take one shot because it overwrites the previous image no matter what you do.

And when the feature does work it's "tacked on". As in, unlike your camera, it will overwrite all it's previous screen shots or prompt you to overwrite them. Entering new file names is only available on some equipment and those it does work on require you to go through several menus to get there. It's a pain. It's far faster to rename all the screen shots on your PC after capturing them via USB thumb drive or camera.
tautech:

--- Quote from: ballsystemlord on March 10, 2024, 03:09:03 am ---Several people so far have pointed out the lack of being able to take screen shots using USB as a bit of missing functionality. I'd like to point out that USB screen shots tend to be a tacked on feature and they don't even necessarily work. Please note that I'm not trying to rant against any of you. I'm pointing out that this really is not a big deal because of how borked it is, at least in my experience.

For example, you have modern equipment that can only take one shot because it overwrites the previous image no matter what you do.

And when the feature does work it's "tacked on". As in, unlike your camera, it will overwrite all it's previous screen shots or prompt you to overwrite them. Entering new file names is only available on some equipment and those it does work on require you to go through several menus to get there. It's a pain. It's far faster to rename all the screen shots on your PC after capturing them via USB thumb drive or camera.

--- End quote ---
Rant you are and lacking in experience shooting your mouth off this way.

Image capture tools in modern equipment are more powerful than you could ever imagine and simple to use.
These are from a SVA1032X that is out the door to a customer tomorrow but a few quick screenshots first and some explanation of how an analyzer works and what screenshots look like.

CW is the setting we most use, Clear/Write in that the previous sweep is cleared as a new sweep is written.
We can sometimes see the sweep marker on the trace as in the cw screenshot half a division before mid display.
BTW, all these were named in seconds before saving to USB or Local using the front panel alphanumeric keypad.

Should we want sweep stopped for a screenshot we use View to stop the sweep and take the picture or to preserve the sweep and activate an additional trace with different settings.

Finally most modern equipment has internal storage for screenshots and all manner of required captures, be it a calibration file in the case of one of these VNA's or just for reference files of which we with the File Manager shift to USB, copy from USB, delete, copy/paste etc.
The File Manager screenshot was first saved to Local memory then shifted to USB and brought here as an example of this functionality.

BTW, all this functionality and more is even present in the cheapest analyzer from Siglent, SSA3015X Plus.

Further reading of capabilities starts here, albeit with the the earlier SSA3000X series:
https://www.eevblog.com/forum/testgear/siglent-ssa3000x-spectrum-analyzers/msg958295/#msg958295
baldurn:
It is an interesting topic. I don't know too much about the old hardware but I researched some of the options given by G0HZU. I know my Siglent SSA3032X-R (all features unlocked and unlocked bandwidth of 7.5 GHz). Given the purpose of testing some wireless device at 2.4 GHz this is what I suspect is useful and not present in the old HPs:

Modulation analysis for digital modulations. AM/FM, ASK/FSK/PSK/MSK/QAM. How are you going to know if your modulation is any good with the old device?

Real Time Analysis Mode. The Siglent can do 40 MHz of real time bandwidth. Needed to be sure to capture short bursts of data transmission.

Network connected. The talk about screenshots - we do these from our PC connected by ethernet (usb is supported also but I never do it that way). None of the problems you mention are actually a problem with this modern device.

Working with a modern UI that has touch screen and option for using a mouse.

It is probably faster (scan time etc) but I don't know for sure.

It has 1 Hz RBW (the HP has 10 Hz) but other than that, I don't necessarily think you should be comparing specs. Is the VNA not as good as the old HP? I don't know but it gets the job done just fine. Unless you have a special need that is depending on these specs, it should be more about which instrument have the needed features.

Cheaper? Maybe but anyway the Siglent is within the stated budget and is a single device with both SA and VNA. But you need to hack it or pay a lot more.
zrq:

--- Quote from: nctnico on March 10, 2024, 01:30:09 am ---Where is comes to actual equipment recommendations:
Many base station analysers have spectrum analysis and network analysis features. I got one from JDSU / Viavi which does both. These typically don't break the bank. The JD745B/JD785B models could be interesting but make sure to understand the available options versus what is installed on the units.

--- End quote ---

I also got a JD785A, which one can get on eBay for ~$2k with the SOL cal kit. It do have okay RF performance on datasheet, in particular for SA dynamic range (2/3 (TOI-DANL) in 1 Hz RBW: >104 dB) and phase noise (typ. –112 dBc/Hz at 1G, 100k offset), and it's modern, portable and hackable. Data saving, remote control and transferring is a piece of cake as there is LAN and USB, and one can be creative as there is a modern linux system running on armv7 inside serving SSH, HTTP and FTP.
Also 7x5A and 7x5B seems to be identical except the useless RFoCPRI function, unless you want to play with RRUs.

However, one should understand their limitations before getting one (or E7495A/B or other Agilent handhelds that are not FieldFox), not only the limitations visible on the datasheet like the dynamic range of the VNA mode is only 80 dB (which is not better than the budget Siglent 3.2 GHz VNA, the higher frequency Siglent is 20 dB better IIRC), and also hidden caveats like

1. AM/FM demodulation is not continuous but only limited to a certain record length.
2. Marker readout is too slow to use.
3. The CW generator is noisy and have poor harmonic rejection.
4. Somehow the video triggering for gated sweep doesn't seem to work, it always stays in free running.
5. Bugs exist like recalling VNA settings with calibration can led to garbled reading. (the latest and likely the last firmware revision)
6. The VNA does not measure phase and magnitude simultaneously (at least I couldn't get it to), but need two measurements to get the complex data.
7. Forget about using the cellular analysis functions to look at generic complex modulated signals, it will likely require a significant amount of hacking.
8. The VNA only uses a very very basic calibration model, assuming the cal kit is ideal.

If I had 2x of the available budget, I should have got myself Siglent SSA3032X-R instead of this. But hey, for only $2k one can get a bundle of a 8G SA and 6G VNA, they should work for your transceiver development despite their limitations. The handheld form factor make it not only ideal for field work, and also in the lab much less head scratching moments realizing the cable is not long enough.
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