Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 14550696 times)

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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16700 on: September 22, 2018, 12:00:01 am »
That 2020 is just... Nipply.  >:D

In Other News...

Testing with my DE-5000 indicates the battery gauge and LVC are quite compatible with 2 cell Lixx operation.

3-2 bars transition: 9.05V
2-1 bars transition: 8.25V
1-0 bars transition: 7.49V
Low Battery Cutoff:6.80V

And for those playing along at home... My checks of my 189, after a 30 minute warmup on the AD984:

10V: 10.003V
7V5:   7.503V
5V:   5.0017V
2V5: 2.5019V

mnem
I intend to be unbearably pleased with myself for at least the rest of the afternoon.  :-DD
Those results aren't too shabby are they, certainly more than good enough to call that 189 as being in calibration  :-+

Pleasingly, the PD202oB PSU is better :)

I forgot to point out that the 2020's indicators are neons (not LEDs), and they flash to indicate an overload. There's something homely about neons.

Although you can dial up voltages in 1mV steps, the 1mV vernier pot allows voltages to be tweaked to microvolt levels. Once set at, say 100mV, the value stays rock solid at 0.100000V, as measured on an HP DVM with 1uV resolution. In contrast, eyeballing my Tenma PSU gives 50uVpp variations.

There's somethiing just right about these 2020B PSUs; definitely a keeper.
Yeah; I think the last one of those I saw was on an episode of The Outer Limits. LOVE that show. ;) Still a gorgeous bit of hardware.

BTW, I certainly hope you mean homey, as in hearth and home... homely means ugly as a mud fence; as in don't let it outside of your home. ;)

Or is this one of those "Queen's English" things I don't know about?

mnem
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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16701 on: September 22, 2018, 12:19:56 am »
BTW, I certainly hope you mean homey, as in hearth and home... homely means ugly as a mud fence; as in don't let it outside of your home. ;)

Or is this one of those "Queen's English" things I don't know about?

Well, as a man who has just implied that his native language is Dumbfuckistani, it's quite understandable that you don't get the finer points of English.

Quote
homely |ˈhəʊmli|
adjective (homelier, homeliest)
1 Brit. (of a place or surroundings) simple but cosy and comfortable, as in one's own home: a modern hotel with a homely atmosphere.
• simple and unpretentious: homely pleasures.

Can sometimes, but not often, be used to imply some of the same sentiments as the German gemütlich.

Oh, and the Brit for "homely" in the sense used in Dumbfuckistan is "face like a bag of spanners*".

*[Amer.] Wrench
« Last Edit: September 22, 2018, 12:29:40 am by Cerebus »
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16702 on: September 22, 2018, 12:56:51 am »
I assure you... I am NO NATIVE Dumbfuckistani... nor is my wife. My children however.... will have to live with that curse for the rest of their lives.  :palm:

But hopefully, we'll be elsewhere before they become irreversibly contaminated. ;)

I am quite conversant in 'merkin English, however... therefore my question about this usage of homely.

Over here, the similar colloquialism is "dumb as a bag of hammers" or "about as sharp as a sack of wet mash".  :o

Being both a machinist and a mechanic, of course I know what a spanner is; in fact, we use it to describe a specific TYPE of wrench which uses a hook or peg as the torque transfer point. It is my understanding that Brits use it to describe a type of adjustable wrench we call a Crescent wrench, after the brand that made them a household item in the same way we call all locking pliers "Vise-Grips".

mnem

« Last Edit: September 22, 2018, 12:59:43 am by mnementh »
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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16703 on: September 22, 2018, 01:12:21 am »
... in the same way we call all locking pliers "Vise-Grips".

Just for reference Mole Grips here.
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16704 on: September 22, 2018, 01:52:24 am »
Hmmmm... I keep a pair of pliers just for nipples. Is this something like that?    >:D

mnem
"Do not use pliers on your nuts; it tends to strip them." ~ grand-dad  :-DD
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Offline Brumby

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16705 on: September 22, 2018, 03:04:05 am »
I am quite conversant in 'merkin English ...

You might want to check out the word "merkin" before using it in a sentence.
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16706 on: September 22, 2018, 03:33:20 am »
I am fully aware of the literal definition of the word;  >:D it was chosen as a deliberate jibe against the locals whose nearly constantly slurred speech turns the name of our great nation into some variant of "mur-rica".

Glad you noticed.  :-DD

mnem
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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16707 on: September 22, 2018, 03:55:00 am »
I am fully aware of the literal definition of the word;  >:D it was chosen as a deliberate jibe against the locals whose nearly constantly slurred speech turns the name of our great nation into some variant of "mur-rica".

Glad you noticed.  :-DD

mnem
*Sent by microwaving an 8mm wrench*

I started using it when I heard George W Bush in a televised speech say "I'm proud to be a 'merkin." and promptly collapsed in giggles. If it's good enough for dubbya...
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Offline Brumby

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16708 on: September 22, 2018, 04:17:51 am »
I am fully aware of the literal definition of the word;  >:D it was chosen as a deliberate jibe against the locals whose nearly constantly slurred speech turns the name of our great nation into some variant of "mur-rica".
Ah.  Nicely played.

Quote
Glad you noticed.  :-DD
I did ... immediately ... but I almost didn't say anything.
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16709 on: September 22, 2018, 05:23:38 am »
I am fully aware of the literal definition of the word;  >:D it was chosen as a deliberate jibe against the locals whose nearly constantly slurred speech turns the name of our great nation into some variant of "mur-rica".
Ah.  Nicely played.

Quote
Glad you noticed.  :-DD
I did ... immediately ... but I almost didn't say anything.

Well this ignorant Yankee had no idea what a "merkin" was. I do now.  :-DD :-DD :-DD

P.S. I don't speak like that anyway. Makes you sound like a dumb redneck.  :palm:
An old gray beard with an attitude.
 

Online tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16710 on: September 22, 2018, 07:08:09 am »
Pleasingly, the PD202oB PSU is better :)

I forgot to point out that the 2020's indicators are neons (not LEDs), and they flash to indicate an overload. There's something homely about neons.

Although you can dial up voltages in 1mV steps, the 1mV vernier pot allows voltages to be tweaked to microvolt levels. Once set at, say 100mV, the value stays rock solid at 0.100000V, as measured on an HP DVM with 1uV resolution. In contrast, eyeballing my Tenma PSU gives 50uVpp variations.

There's somethiing just right about these 2020B PSUs; definitely a keeper.
Yeah; I think the last one of those I saw was on an episode of The Outer Limits. LOVE that show. ;) Still a gorgeous bit of hardware.

BTW, I certainly hope you mean homey, as in hearth and home... homely means ugly as a mud fence; as in don't let it outside of your home. ;)

Or is this one of those "Queen's English" things I don't know about?

Well, my google for "homely" gives:
  homely/ˈhəʊmli/
  adjective
      (of a place or surroundings) simple but cosy and comfortable, as in one's own home.
      (of a person) unattractive in appearance.

I was thinking of the first definition rather than the second - which is definitely inapplicable in this case!
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
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Online tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16711 on: September 22, 2018, 07:11:02 am »
I assure you... I am NO NATIVE Dumbfuckistani... nor is my wife. My children however.... will have to live with that curse for the rest of their lives.  :palm:

But hopefully, we'll be elsewhere before they become irreversibly contaminated. ;)

Unfortunately everywhere (and particularly the UK over the past few years) could be called "Dumbfuckistan" :(

Fortunately children are resilient, and will be invisibly picking up your attitudes (even when you wish they wouldn't).
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16712 on: September 22, 2018, 08:38:20 am »
Dumb and fat, that's what "merkin" has become. NSFW because of language and you'll hear "shitballs!"  :-DD

An old gray beard with an attitude.
 
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Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16713 on: September 22, 2018, 08:53:29 am »
So I’ve just crawled out of bed at 09:30 after a heavy night of being old and boring and this thread has taken another random fork. I’m genuinely amazed. It’s like going to the pub but cheaper and better company than the locals.

Now as SWMBO is out I’m going to go hunting some bacon. Then warm up the soldering iron and fix something.

Edit: so I’m about to be the owner of a spectrum analyser. Next step, assuming it works, is a wideband noise source. Was thinking about using a reverse biased transistor BE junction and some MMIC amps and throw this out of an SMA connector. Another PCB making excuse as well there :)
« Last Edit: September 22, 2018, 09:30:59 am by bd139 »
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16714 on: September 22, 2018, 09:58:49 am »
Classy chinese test gear here...



 :palm:

Going to design my own. Found some really cheap MMICs (NXP BGA2867).
 

Offline Wolfgang

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16715 on: September 22, 2018, 10:16:13 am »
... not only the name is a bit crippled, just have a look at the spectral flatness ...

Some ideas here:

https://electronicprojectsforfun.wordpress.com/making-noise/
 
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Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16716 on: September 22, 2018, 10:26:31 am »
Thanks for the link - will have a read :)

I noticed the flatness was poor. I'm not terribly worried about that though. The use case for this is mainly crystal filter shaping/selection and narrow IF filter alignment so the spectral flatness is less important across the entire range as long as it's not terribly variable in the very narrow frequency range of the filter. Most of the filters I build I can sweep through my DDS + power sensor combo on a scope and get an SNA type output.

Going to attempt to use a 7.5V zener as a noise source. I've crudely measured the power out of one of these this morning at approx -80dBm with an AD8307 detector and 40dB gain stage I already built ages ago (no SA yet so don't know what the spectrum looks like). I'll stick this through 2x 26dB gain stages with a BGA2867 each and then a 3dB matching pad. That should give around -25dBm out which is fine for this sort of stuff. I will make the PCB flexible enough to swap bits out if I get my numbers wrong.

Mainly interested in slightly better than "winging it" which is my current approach  :-DD

Edit: just seen there's a sale on Rigol SA's at the moment. DSA705 which is fine for me is £660 inc. Hmm. Wonder if I could pay half of one of those off with that 7L12 :D
« Last Edit: September 22, 2018, 10:29:36 am by bd139 »
 

Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16717 on: September 22, 2018, 10:37:35 am »
I've had good results in the past from using a transistor BE junction as a zener noise generator. Even the humble 2N3904 will spit out quite respectable power and bandwidth.

Quick look back through some old notes shows getting about -60dBWrms raw noise out of a 2N3904. Can't find a note on the bandwidth, must have it somewhere...
« Last Edit: September 22, 2018, 10:58:21 am by Cerebus »
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Offline Wolfgang

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16718 on: September 22, 2018, 11:11:42 am »
I dont know the 705, but I have the 815TG and its very OK. There is simply no more bang for the buck. What the entry level RIGOLs need, however,
is an external preamp for noise work. Their DANL is simply not good enough. Its easy to make some yourself, and then everything looks really pretty, noisewise:

https://electronicprojectsforfun.wordpress.com/making-noise/using-homebrew-preamps-in-commercial-noise-figure-measurement-applications/

 
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Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16719 on: September 22, 2018, 11:40:47 am »
I was actually going to buy an 815 with the tracking generator originally but I’m not sure I’ll extract the cost’s worth of value out of it. Annoyingly one went on eBay the other day for £425 buy it now from someone who didn’t know what it was worth. Was annoyed I missed that! The 7L12, if it works, will do the job and if I use it enough will result in a justified purchase.

Thanks both for the tips. Much appreciated.

When I put a board together I will design it with the objective of being able to replace the noise source and do some experiments. I’ll make up three boards as well as OSHpark do three per lot anyway.
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16720 on: September 22, 2018, 03:51:01 pm »
Dumb and fat, that's what "merkin" has become. NSFW because of language and you'll hear "shitballs!"  :-DD

[George Carlin Video on American Consumerism]

George was always one of my favorite social commentators... and even being a fat fuck myself, I have to admit every word he says there is the absolute unvarnished truth. The really sad part is that set was recorded during The Shrub's reign of Idiocy and Avarice; and if anything, all of it is truer now than ever.  :palm:



However, I found the episode of Leno's Garage that followed a lot more fun...  :-DD

mnem
*Currently stalking coffee and a plate of biscuits with orange marmalade* As craptacular as I feel right now, they might just get away...
« Last Edit: September 22, 2018, 05:59:55 pm by mnementh »
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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16721 on: September 22, 2018, 04:20:13 pm »
To follow that there's only thing apart from Holy Shitballs and thats this

Who let Murphy in?

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Online xrunner

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16722 on: September 22, 2018, 05:03:16 pm »
Another run of DMMCheck Plus is going to happen so I'm not missing out this time, just ordered it -

DMMCheck Plus

I told my friends I could teach them to be funny, but they all just laughed at me.
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16723 on: September 22, 2018, 06:46:35 pm »


grr. arrg.

mnem
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« Last Edit: September 22, 2018, 06:49:34 pm by mnementh »
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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #16724 on: September 22, 2018, 07:30:07 pm »
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 


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