Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

I dunno... I agree with C as far as the need to store images on the eevBlog servers, manky as SMF is. 

I often even do it with other people's images when posting a reply to someone else's post, so that at least one copy of images with important technical relevance gets stored directly with the post "for posterity". I mean, yeah it's a bit of a PITA; but I got used to doing it decades ago when there was no other way, so I guess I'm a "moderately lazy" ol' bastahd dwagon. 

mnem
 

[Vince]

Yebbutt... for someone who appreciates the virtues of FOSS, seems to me you'd be more than willing to deal with occasionally having to do the work by hand. I mean, [inline imaging] is just a convenience added to SMF for (l)users who can't be arsed to think and learn a few simple keystrokes... 

If I have to fuss that much to include a fucking image, I actually CBA. What I should do, is to fix TLS (because HTTP img tags in TLS served HTML is not kosher.) on my web server, because as things stand today, copying the image into the AFS volume that the web server can read from, and then IMG-tag that link is orders of magnitude better. Also, I can make images as large and plentiful as I want. (Poor Vince!)

Now, there's a Sunday project.

*goes away to mess with an apache config*

NOOOOOOOO !!!!!   

[Cerebus]

If I want, I can pick those values off my smart meter using RS232. I have a project to do that, actually.

If that's not enough, I'll buy an used Janitza power monitor and poll it frequently.

It's not as viscerally satisfying as a proper paper chart recorder keeping tabs on it all. Plus if you lose power completely you can still read the paper chart.

By candle light if necessary. 

There's a serious point here about the quality and usability of modern user interfaces versus more traditional ways of doing things. When I want a bench PSU for something I inevitably pull out one of the old ones that have real, proper 10 or 25 turn knobs for the voltage and current settings. I've got two HP measurement PSUs that are better in every regard - electrically - but require me to tap in the voltage and current on buttons, and promptly forget what they were set to when they are powered off (as opposed to the outputs turned off). Both the measurement supplies are at least one digit both more precise and accurate than the old truly analogue supplies but they languish because the old supplies are so much easier to use.

The same with a putative chart recorder. If I had one, a glance at it would tell me the state and history of the mains supply. Like Mäns, I could get that from a smart meter, but it would require complex interfacing, hitting buttons to display the figures I wanted (or hitting a web page) and generally be more fuss than just standing up, walking to the chart recorder and just glancing to get the full picture.

Sadly I think for instrumentation we are still groping blindly to find modern, mostly digitally implemented, user interfaces that are better than the analogue user interfaces they replace.

[Cerebus]

I just realized I have no idea how to use a VNA.

Don't worry you're in good company. While I have a vague idea how to use one, I've never had to do so "in anger".

[mnementh]

NOOOOOOOO !!!!!   

mnem
I dare you: https://photojournal.jpl.nasa.gov/archive/PIA23623_hires.tif 

[mnementh]

I just realized I have no idea how to use a VNA.

Don't worry you're in good company. While I have a vague idea how to use one, I've never had to do so "in anger".

https://www.tek.com/en/documents/primer/what-vector-network-analyzer-and-how-does-it-work

mnem
Look honey... I contributed!!!   

[Cerebus]

Hi!
You seem to have crash-landed
your planetary lander.
Do you need help with that?

[Vince]

NOOOOOOOO !!!!!   

mnem
I dare you: https://photojournal.jpl.nasa.gov/archive/PIA23623_hires.tif 

Only 2.3GB and 2 hours download time according to Firefox.... because my 4G modem seems in good shape this evening, freaking 350kB/s  wow! 
I wish it were like that 24/7....

[mnementh]

Hi!
You seem to have crash-landed
your planetary lander.
Do you need help with that?

KILL IT!!! KILL IT WITH FIRE!!!

mnem
Then pour kerosene on the ashes and burn them again!!! TAKE NO CHANCES!!!

[Neomys Sapiens]

I bought a thing. Rather cheaply, given that it is tested and only has a slight display impairment.
So I am owner of a functional 500MHz programmable Noise Generator now. Anyone in need of getting his signals noisified?

[Robert763]

I just realized I have no idea how to use a VNA.

Don't worry you're in good company. While I have a vague idea how to use one, I've never had to do so "in anger".

I have 5, do you want one?
The first thing to learn about using VNAs is that to get accurate measurements the required accessories will cost more than the analyser. You will aquire test sets, cables, opens, shorts, terminations and adaptors that are only used for the VNA.

[Neomys Sapiens]

Maybe of interest if anyone needs the power cord (see picture #5):

https://www.ebay.de/itm/165360477522

[Cerebus]

Anyone in need of getting his signals noisified?

I have neighbours for that.  I'd swear that when he was about 2 years old that the lad next door produced broadband noise flat from about 1 1kHz to 2MHz.

[tautech]

I just realized I have no idea how to use a VNA.

Them not so bad providing you initially apply KISS principles.

Single port reflective measurements on antennas is a good place to start to become comfortable with a VNA but as Robert points out the rabbit hole awaits ! 

By no means a tutorial my initial adventures with VNA's may offer some ideas:
https://www.eevblog.com/forum/rf-microwave/what-really-is-this-antenna/

[Cerebus]

I just realized I have no idea how to use a VNA.

Don't worry you're in good company. While I have a vague idea how to use one, I've never had to do so "in anger".

I have 5, do you want one?
The first thing to learn about using VNAs is that to get accurate measurements the required accessories will cost more than the analyser. You will aquire test sets, cables, opens, shorts, terminations and adaptors that are only used for the VNA.

The truth is that I have no real use for one. The only thing that I'd currently be able to do with one that I can't at the moment (at least not easily), is to connect a Metcal iron to one and wave magnets around near the tip to find the best placement for them in making my dumb stand into a magic power saving one.

[Ice-Tea]

The first thing to learn about using VNAs is that to get accurate measurements the required accessories will cost more than the analyser.

Need to get something out of the damn thing before I worry about accurate 

[Martin.M]

https://wellenkino.de/hp/5245l/voltmeter.mp4

my counting voltmeter 

[VK5RC]

I bought a thing. Rather cheaply, given that it is tested and only has a slight display impairment.
So I am owner of a functional 500MHz programmable Noise Generator now. Anyone in need of getting his signals noisified?

Some time ago I built some very low noise amplifiers to use as a feed point amp for earth-moon-earth amateur radio signal bouncing. One of the most expensive and least looking-like how-much-it-cost items I have ever bought were 2 keysight calibrated noise sources. I was very happy with my amps (37dB gain, 0.4 noise figure at 1296MHz) but kept blowing their brains out with an error in the transmit-receive sequencing - they don't like 400W up-em the wrong way!
I got so peeved that it is all sitting on the shelves of repair (shame) 😁
I don't know if you can link that unit up to an HP noise figure analyzer but looks like it would 👍

[Neomys Sapiens]

The first thing to learn about using VNAs is that to get accurate measurements the required accessories will cost more than the analyser.

Need to get something out of the damn thing before I worry about accurate 

Ok, which unit is it? Maybe I could guide you to a point where you ought to see something.

[Neomys Sapiens]

I bought a thing. Rather cheaply, given that it is tested and only has a slight display impairment.
So I am owner of a functional 500MHz programmable Noise Generator now. Anyone in need of getting his signals noisified?

Some time ago I built some very low noise amplifiers to use as a feed point amp for earth-moon-earth amateur radio signal bouncing. One of the most expensive and least looking-like how-much-it-cost items I have ever bought were 2 keysight calibrated noise sources. I was very happy with my amps (37dB gain, 0.4 noise figure at 1296MHz) but kept blowing their brains out with an error in the transmit-receive sequencing - they don't like 400W up-em the wrong way!
I got so peeved that it is all sitting on the shelves of repair (shame) 😁
I don't know if you can link that unit up to an HP noise figure analyzer but looks like it would 👍

A noise source with that range would be useful in my company lab for exactly the same application. But I am not personally hunting for one, except it comes to me by chance. Good data on that amps, btw.

And don't worry - we all have such shelves!

[cyclin_al]

NOOOOOOOO !!!!!   

mnem
I dare you: https://photojournal.jpl.nasa.gov/archive/PIA23623_hires.tif 

That is nasty!    I cancelled when I realized that even with my brand new DSL modem (yep, it got replaced AGAIN on Friday) it was going to take 4.5 hours...

[Ice-Tea]

The first thing to learn about using VNAs is that to get accurate measurements the required accessories will cost more than the analyser.

Need to get something out of the damn thing before I worry about accurate 

Ok, which unit is it? Maybe I could guide you to a point where you ought to see something.

HP8753E. Don't worry about it too much though. I actually like figuring stuff like that out It's just that time is always in short supply

[mnementh]

NOOOOOOOO !!!!!   

mnem
I dare you: https://photojournal.jpl.nasa.gov/archive/PIA23623_hires.tif 

That is nasty!    I cancelled when I realized that even with my brand new DSL modem (yep, it got replaced AGAIN on Friday) it was going to take 4.5 hours...

Mmmmhmmmm... it appears that NASA (or some hop in between) is capping the B/W at around 1.7MB/sec... I get same throughput whether on the WiFi adapter or GBE direct to the gateway. 

mnem
 

[mnementh]

Today I cleared space over half the attic, emptied a bedroom, moved 5 bookshelves, 2 bedframes and a dozen full bins up/downstairs, then refilled 2 bedrooms. Ouchies, Mister Sqweek...

mnem

[Neomys Sapiens]

The first thing to learn about using VNAs is that to get accurate measurements the required accessories will cost more than the analyser.

Need to get something out of the damn thing before I worry about accurate 

Ok, which unit is it? Maybe I could guide you to a point where you ought to see something.

HP8753E. Don't worry about it too much though. I actually like figuring stuff like that out It's just that time is always in short supply

Well, it would be easiest if you have a known good filter or something close to it with a transition frequency in the single or double digit MHz range. Connect to both ports. Somewhere you can set the stimulus level - go for -10dBm. Then set center and span (or start/end) of frequency to cover the expected transition and well beyond ond both sides. Go for a S21 measurement. 10dB/div and Ref 0dB. Then you should see something like the attached picture for a LP filter. (frequency is a lot higher, but using a lower frequency like I suggested would make calibration and connections less critical).