Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 2438010 times)

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Online tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47300 on: January 17, 2020, 03:44:56 pm »
... reduce the problem to an accurate reference capacitor ...

And there's the chicken and egg problem. How do you get an accurate reference capacitor without a decent LCR meter to measure it with?  :)

Have patience, spend money on fleabay for a reference mica capacitor for a cal lab - preferably with its measured value marked on the side.

My largest is 500nF :)
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Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47301 on: January 17, 2020, 04:02:21 pm »
That's a pretty big and expensive capacitance for mica that!

Exactly. 2-5% is mostly fine if you design your RF-ey circuits for worst case parameters or make them tunable. And a 1% capacitor will get you there.

And for what use are then the 0.3% capacitors? Cannot imagine, that the Russians made them just for fun.

It's a good question. Near near zero temperature coefficient on the other hand tends to be more important than absolute values.
 

Offline worsthorse

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47302 on: January 17, 2020, 04:02:57 pm »
For me it was the Dick Smith ESR meter:-+ It was my first electronic kit that actually yielded a usable tool; while I'd built many "Lab kits" and repaired a number of Heath products I never built one.

For the curious, the AADE LCIIB manual is here as a pdf.

mnem
*toddles off to ded*

I have one - really useful, the kit is still available, not cheap though https://www.altronics.com.au/p/k2574-esr-meter-kit/
Rob
Its still a very basic device so is expensive for what it does. you can get more comprehensive devices on the market, cost less ans just as accurate that will do more as well.

It is basic and, yes, there are better price/performance options now but there weren't such options when it was released.  Like my palomar engineers noise bridge and autek RFA kit, this is one of those "classics" of ham radio test gear. And for the stuff most of us amateur radio operators did and do, it is plenty accurate.

Today, we have gear like the nanovna and the antduino in the same mold. Owen duffy can tell you all the ways the nanovna fails (and he is correct) but  for a lot of non-professional users, within certain constraints, it does a great job and fills an otherwise un-fillable hole.
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Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47303 on: January 17, 2020, 04:22:16 pm »
Indeed. It's nice to grab some stuff you missed the first time round or were too broke to do at the time. One reason I built the Norcal 40A. Got a project queue a mile long now.

Edit: actually perhaps that's the foundation of TEA: "buying shit you couldn't afford the first time round" :)
« Last Edit: January 17, 2020, 04:25:09 pm by bd139 »
 
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Online med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47304 on: January 17, 2020, 04:27:47 pm »


Edit: actually perhaps that's the foundation of TEA: "buying shit you couldn't afford the first time round" :)

Ahem. Remember these days?  :P :P :-DD :-DD
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Offline WastelandTek

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47305 on: January 17, 2020, 04:28:55 pm »
exactly

Just how in the hell was a broke hobbyist supposed to measure an inductor or low pF cap in frigging 1998?

I well remember the first time I was able to design a 2M LPF in ladpac, verify the inductor values with the LCIIB, and have it actually land pretty dammed close to perfect when implemented...oh the joy.
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Offline worsthorse

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47306 on: January 17, 2020, 04:29:35 pm »
Of a more TEAish flavor,  I was lucky enough to acquire one of these recently:

(Attachment Link)

A still-in-the-bag AADE LC meter kit, legendary among ham radio operators of a certain bent, at least in the United States. Another recent arrival is a first generation Norcal 40 kit, also still in its original bag.   :-+

I think I am going to set aside working on test gear for a bit and build me some electronics.  After, of course, I put the dryer back together and figure out exactly where the HVAC guy hid the damper actuator for the second floor heating so I can replace it.

That was a good find. I’ve been after one of those for about 5 years. And typically as is always with stuff on my build list, the dude went SK  :(. RIP.

I know... my want-to-buy kit list seems to be heavy on stuff (Clifton Labs, W4RT, G4HUP, AADE come to mind) that I found out about a month after the kit was retired or the shop closed or the owner retired or became a silent key.

These days I watch and wonder at people like Hans Summer. The time and energy they invest in answering every kind of question, from the brilliant to the completely moronic, about a fifty dollar kit is amazing. I have a great respect for designers that become producers as I'd wouldn't last a month doing what he does!
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Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47307 on: January 17, 2020, 04:34:24 pm »
Yeah happens. Small businesses suffer from this all the time unfortunately. The public recognition of the deceased ham though is somewhat larger than other circles. Call signs can live on longer than the owner.

Hans is crazy good. He's on a few other lists I'm on as well participating regularly. Then again if I remember correctly from a conversation a few months back from someone entirely not involved in radio, he did actually make a fuck load of money as a fundy somewhere then retired to Turkey to make kits all day :). I still don't get Turkey though. Why there?!?!?!  (disclaimer: may have been a different Hans Summers but they came from same area so possible)
 

Offline ThickPhilM

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47308 on: January 17, 2020, 04:34:51 pm »
This looks interesting, but I don't have either time or space for it atm...   :-\

https://www.ebay.co.uk/itm/Tektronix-Rackmount-Oscilloscope-w-Modules-MOD135J-OP7/352936898093
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Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47309 on: January 17, 2020, 04:35:53 pm »
Run away. It's a 5000 series.

2, yes TWO megadoodles of bandwidth.

Edit: Anyway I need to go do some work now the compiler has done its job finally! :-DD
 

Offline WastelandTek

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47310 on: January 17, 2020, 04:50:02 pm »
I'm actually a big fan of 5000 series scopes, the faster 54xx ones are quite useful around the shack.

Big displays, easy to work on, reasonably priced compared to their 7000 bretheren

references here http://www.i9t.net/5000_scopes.html

thread here https://www.eevblog.com/forum/testgear/tektronix-5000-series-(1970-1990-era)-shenanigans/
« Last Edit: January 17, 2020, 04:51:42 pm by WastelandTek »
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47311 on: January 17, 2020, 05:21:01 pm »
For me it was the Dick Smith ESR meter:-+ It was my first electronic kit that actually yielded a usable tool; while I'd built many "Lab kits" and repaired a number of Heath products I never built one.

For the curious, the AADE LCIIB manual is here as a pdf.

mnem
*toddles off to ded*

I have one - really useful, the kit is still available, not cheap though https://www.altronics.com.au/p/k2574-esr-meter-kit/
Rob
Its still a very basic device so is expensive for what it does. you can get more comprehensive devices on the market, cost less ans just as accurate that will do more as well.

Not quite true in this case.

The test method of the AADE one is much much better for lower value parts (pF / nH). The DER5000 and the Peak units use an impedance bridge whereas the AADE uses an LC oscillator and counter and some clever mathematics which reduce the problem to an accurate reference capacitor and differential measurement of frequency which cancels all the fixture and cable parasitics automatically. Thus the AADE one potentially has a higher resolution and better parasitic immunity and auto nulling than all the other units on low value parts which are present in radios in large quantities.

You can build your own naive one with the instructions here, a frequency counter and a calculator or desktop PC program to crunch the numbers: https://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/73/1990/09/page48/index.html

In principle, I agree. In practice, the AADE unit was groundbreaking, but flaky as hell in daily use.

I think the design demands too much precision of the "precision" parts used as reference and elsewhere in the circuit; updating with modern equivalents might make the readings not flutter like a geisha if you breathe on it. That and its design basically being centered around small value ceramic caps & inductors limited its usefulness as a diag tool for consumer/computer electronics. :-//

I HAD both when I was living the "pro fixer" life. On a service bench anyways, they're more of a historical curiosity than a troubleshooting tool. IMO, YMMV, DQMOT, etc. ;)

mnem
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47312 on: January 17, 2020, 05:30:56 pm »
Yeah it's more a forward engineering than diagnostics tool for sure. My LCR45 sits somewhere between which I'm happy with.
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47313 on: January 17, 2020, 05:32:53 pm »
Run away. It's a 5000 series.

2, yes TWO megadoodles of bandwidth.

Edit: Anyway I need to go do some work now the compiler has done its job finally! :-DD

Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47314 on: January 17, 2020, 05:58:14 pm »
... reduce the problem to an accurate reference capacitor ...
And there's the chicken and egg problem. How do you get an accurate reference capacitor without a decent LCR meter to measure it with?  :)
How about machining a capacitor in a vacuum with a very precise and well-known geometry? What accuracy can be achieved, when you calculate then the capacity and measure it?

Edit:Something similiar like this:

Now we know what's in Herman Munster's neck.  :-DD

mnem
Please excuse mnem; he was up 'til the buttcrack of dawn resurrecting a laptop which had been beaten to death by his son. His associations have become somewhat loose of late. :o
« Last Edit: January 17, 2020, 06:21:58 pm by mnementh »
 
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47315 on: January 17, 2020, 06:18:12 pm »
(SNIP) Like my palomar engineers noise bridge and autek RFA kit, this is one of those "classics" of ham radio test gear. And for the stuff most of us amateur radio operators did and do, it is plenty accurate.

Today, we have gear like the nanovna and the antduino in the same mold. Owen duffy can tell you all the ways the nanovna fails (and he is correct) but  for a lot of non-professional users, within certain constraints, it does a great job and fills an otherwise un-fillable hole.

The nanoVNA is one of those intriguing tools; the resonance circuit is so damned flexible that it is like a Swiss Army Knife, the same way as the bridge in the Atmega Component testers. As the design of those component testers continues to refine it becomes less and less hardware dependent and more self-healing/self-calibrating in the software; I see the same kind of evolution happening in the nanoVNA and before long lots more functionality derived primarily from the software. Exciting times to be a hobbyist.  :-+

Agreed on the AADE kit; like I said earlier... I'd happily build it or the Dick Smith ESR meter kit again if it came my way at a reasonable price. ;)

mnem
*makes mental note to revisit the nanoVNA on eBay.ca*
« Last Edit: January 17, 2020, 06:21:27 pm by mnementh »
 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47316 on: January 17, 2020, 06:26:31 pm »
Yeah nanovna is bloody amazing for the money. I use mine more than the scope at the moment.
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47317 on: January 17, 2020, 06:33:19 pm »
(SNIP) Like my palomar engineers noise bridge and autek RFA kit, this is one of those "classics" of ham radio test gear. And for the stuff most of us amateur radio operators did and do, it is plenty accurate.

Today, we have gear like the nanovna and the antduino in the same mold. Owen duffy can tell you all the ways the nanovna fails (and he is correct) but  for a lot of non-professional users, within certain constraints, it does a great job and fills an otherwise un-fillable hole.

The nanoVNA is one of those intriguing tools; the resonance circuit is so damned flexible that it is like a Swiss Army Knife, the same way as the bridge in the Atmega Component testers. As the design of those component testers continues to refine it becomes less and less hardware dependent and more self-healing/self-calibrating in the software; I see the same kind of evolution happening in the nanoVNA and before long lots more functionality derived primarily from the software. Exciting times to be a hobbyist.  :-+

Agreed on the AADE kit; like I said earlier... I'd happily build it or the Dick Smith ESR meter kit again if it came my way at a reasonable price. ;)

mnem
*makes mental note to revisit the nanoVNA on eBay.ca*

Yeah nanovna is bloody amazing for the money. I use mine more than the scope at the moment.

And the newer version of the nanovna, with the larger screen and some component and layout improvements, looks like it is worth getting, even if you already have one, and independent of the continuing software improvements.

If you are doing stuff under 100MHz, it is a pretty awesome piece of kit.  And you can really learn a lot about RF circuit analysis on the cheap, if you are willing to spend some time building test fixtures, digging through the documentation, experimenting and hanging around the user group. 

specialization is for insects.
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47318 on: January 17, 2020, 07:17:32 pm »

Edit: actually perhaps that's the foundation of TEA: "buying shit you couldn't afford the first time round" :)

For me, that is 100% true. We didn't get an oscilloscope at the place I worked in the early 90s, even if we had a clear need for it, and I had to make do with one of those small pocket multimeters with fixed cables.  Of course, being the times it was, I measured, religiously, every 3-phase outlet we were supposed to use, before we dared connect anything to it. Except a completely insanely dangerous pocket multimeter much like this one... The Fluke 10 I bought for my own money just after that was such an upgrade. Then, I was gifted a ScopeMeter 123, literally on the swedish launch of it, and thus my fate was sealed. I am a Test Equipment Addict. I will acquire. This is if not good, at least satisfying. 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47319 on: January 17, 2020, 08:03:17 pm »
Random Friday evening self designed 3d prints for PCB prototyping...

1. corner drilling template...



2. PCB soldering jig so you can solder bits of it at actual right angles etc



I'm loving this printer and FreeCAD. Autodesk can go to hell  :-DD

The real killer feature is the ability to make new tools with it.
« Last Edit: January 17, 2020, 08:05:06 pm by bd139 »
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47320 on: January 17, 2020, 08:09:14 pm »
Random Friday evening self designed 3d prints for PCB prototyping...

1. corner drilling template...



2. PCB soldering jig so you can solder bits of it at actual right angles etc



I'm loving this printer and FreeCAD. Autodesk can go to hell  :-DD

The real killer feature is the ability to make new tools with it.

.stl ? I could definitely use those.
 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47321 on: January 17, 2020, 08:17:37 pm »
attached.

There are two designs for the corner jig. One with an L shape for right angled corners (front panels) and one with an X for T joints etc. Printed 0.2mm 20% infill :)
 
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Online Kosmic

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47322 on: January 17, 2020, 08:20:35 pm »
attached.

There are two designs for the corner jig. One with an L shape for right angled corners (front panels) and one with an X for T joints etc. Printed 0.2mm 20% infill :)

Thanks  :-+
 
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47323 on: January 17, 2020, 08:36:25 pm »
Another experiment inspired by xrunner's pointy stick. I'm not happy with it yet.



Going to redo it a bit "monty python" :D
 
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Online BU508A

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47324 on: January 17, 2020, 09:06:41 pm »
No wonder, you have used the wrong finger.  :-DD
“Chaos is found in greatest abundance wherever order is being sought. It always defeats order, because it is better organized.”            - Terry Pratchett -
 
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