Test Equipment Anonymous (TEA) group therapy thread

[worsthorse]

That’s a beast isn’t it.

On the subject of beasts guess who just bought a semi boat anchor. Now need to work out how to get it with a fucked arm 

Edit: tek 454 (yeah I know) and just won a PL320 as well. Back on the wagon

well that didn't take long now, did it? 

[worsthorse]

Yeah I’ve had ones that are 60 years old that were good 

Have gone a bit “tonyalbus” on eBay today  . More stuff arriving soon 

Edit: and another offer accepted. Decided “fuck it” was in order. Cupboard of doom will be recommissioned.

no, not long at all, actually. welcome back to the dark side good sir. 

[Specmaster]

Yeah I’ve had ones that are 60 years old that were good 

Have gone a bit “tonyalbus” on eBay today  . More stuff arriving soon 

Edit: and another offer accepted. Decided “fuck it” was in order. Cupboard of doom will be recommissioned.

Maybe you ought to have stayed and waited A&E, your wallet might have been thanking you round about now

[bd139]

Yeah probably right 

[Specmaster]

That Casio I purchased because it had a dickie digit is now well fucked, it has 4 dodgy as hell digits since I had a go at reseating the sticky edge strip connectors on the display, so you can be heartened that one more calculator with a = key has gone to calculator hell 

[bd139]

That's what happens when you use calculators with equals keys 

[Specmaster]

Well at the end of the day, ENTER or EQUAL, you ain't getting an answer till you press one or the other 

[bd139]

Not strictly true with RPN calculators. If it's a unary operator for example 

[Cerebus]

Yup.

Well screw today. Had the day off.  Dropped the car off for service. Decided to run back as it’s a nice route along the river. Fell on my arse after slipping on some gravel and have completely fucked up my elbow  . Joy to the fact I live 5 min walk from the local hospital so I’m going to sit down there and get called an idiot for the rest of the afternoon. Waiting for codiene to kick in first 

On a positive note the car passed MOT with no issues and they even cleaned it and will drive it back to me as I injured myself for free 

Clearly you can't be let out on your own without adult supervision and not get injured. Next time you go out on your own you should wear one of these:



Bonus: beats a mask and/or face shield.

[bd139]

I had one of those built in until I started this fitness shit 

[Mr. Scram]

I christen thy not Penisfingers, but Peniseverything. Dickie for short.

[Wolfgang]

This $10,- Noise Source .. thing adds a lot of value to a SA without TG .. i like it.

Some cautions are necessary when using such "poor man's tracking generators", especially with hiogh-end spectrum analysers.

Make sure there is no DC on the output.

Make sure the total power output across all bands is less than the spectrum analyser's max input power.

Be aware that if there are any non-linearities in the components in the UUT, then intermodulation products will be produced and will be visible as a raised noise floor.

The combination of internpud products plus the limited power in the bandwidth being measured by the spectrum analyser, means the dynamic range will be limited. It may be difficult to see a filter's stopband attenuation.

Nonetheless, such techniques can be useful. I've used them with an SDR dongle to measure filter characteristics and as a poor-man's TDR (resolution 3cm).

... some more things:
- make sure that the frequency response of your noise is FLAT
- AND that the match is VERY good.

otherwise (see Keysight paper about noise figure measurement uncertainty) your measurements can be VERY inaccurate.

A NF of 0.1dB measurement claimed by some LNA guys - ridiculous, except they have been at NIST or PTB.

[BU508A]

Update to my R&S NGB 32 / 10 repair.

Finally I succeeded. Yeah! 
Output voltage: -0.6 ... 36.8V  -  needs adjustment
Output current: not tested yet, need a proper load. All I have actually are two  10 Ohm / 100W resistors

Here is, what I have replaced:


I have no idea what the previous owner did, but with his "repair" attempt he'd managed to toast the 2N3773 and the 2N3583 

This is a nice comparison of these old Roederstein capacitors (yellow, 3300µF / 63V) with a new 3300µF / 80V from RND (this is the brand of reichelt):


And these are the mil-spec 1N823A, looking very nice in their red cases 


I think, I'll write a repair report. I have no idea what this guy had thought when he replaced those  8A slow blow fuses with 10A slow blow ones and blew them as well. 
This damaged the power transistors which otherwise wouldn't have happen.
Moron.   

[tggzzz]

This $10,- Noise Source .. thing adds a lot of value to a SA without TG .. i like it.

Some cautions are necessary when using such "poor man's tracking generators", especially with hiogh-end spectrum analysers.

Make sure there is no DC on the output.

Make sure the total power output across all bands is less than the spectrum analyser's max input power.

Be aware that if there are any non-linearities in the components in the UUT, then intermodulation products will be produced and will be visible as a raised noise floor.

The combination of internpud products plus the limited power in the bandwidth being measured by the spectrum analyser, means the dynamic range will be limited. It may be difficult to see a filter's stopband attenuation.

Nonetheless, such techniques can be useful. I've used them with an SDR dongle to measure filter characteristics and as a poor-man's TDR (resolution 3cm).

... some more things:
- make sure that the frequency response of your noise is FLAT
- AND that the match is VERY good.

otherwise (see Keysight paper about noise figure measurement uncertainty) your measurements can be VERY inaccurate.

A NF of 0.1dB measurement claimed by some LNA guys - ridiculous, except they have been at NIST or PTB.

I don't see the relevance of noise figure. Could you provide the reference, please.

Amplitude non-flatness can be removed by subtracting the response without the UUT from that with the UUT.

[Wolfgang]

Do have a look at the Keysight app note and web calculator, its well explained there.

[tggzzz]

Do have a look at the Keysight app note and web calculator, its well explained there.

I'm probably being dense because I'm tired, but what Keysight app note?

[Saskia]

why our politicians think that electric cars do not pose problems for the grid ...

sorry, German only.
https://www.gunboard.de/uploads/monthly_2020_07/IMG_4346.MP4.4481e17956c060cc4b266af1bd559dc6.MP4

[Neomys Sapiens]

So, bd139, are you off to Stonehouse this weekend to pick up the Solartron DVMs?
https://www.ebay.co.uk/itm/Solartron-Digital-Voltmeters-A203-A202/153999947342

I would have gone to £5 because I don't need them, but fortunately somebody was prepared to pay >£50.

As for Stonehouse, I've only driven along the main road so all I can say it is looks a reasonable place. The only reason I did that was because a local "shared space guru" was pitching to introduce one in my village. He was touting that his introduction of a shared space in Stonehouse had significantly reduced the speed along the main road. Knowing he was a charming bullshitter, I went and had a look. The shared space was only 50m long and was preceded by 9(!) speed ramps.

The nearby Stroud centre isn't bad, has an excellent farmers' market, and lots of Artistes including Damian Hurst's factory. It has a reputation that the aggies from the surrounding 5 valleys descend there on Saturday night.

Unfortunately not me. I had to cancel as my car is going in for service today and the air con is bust so I’m probably going to lose it over the weekend

Oh god a town planning cult. Don’t put me off the place  . It’s pretty nice particularly the north side. I was looking at this which is sufficient for my needs https://www.rightmove.co.uk/property-for-sale/property-93276722.html .

Best bit is all the hills 

(Attachment Link)

Edit: a point I’m sure will be made about lab space but I’ll rent a local office for that and work. By the time I’ve finished working the kids will have buggered off so I’ll move the TE back into the house

Looks old and musty. Cloudy and rainy. Quaint. With sheep roaming the hills and perverted shepherds. 

So typical English. 

That scenery looks to me like a totally forlorn medieval hovel.

Sheep are stupid and clogging the drainage pipes.
Here you see a specimen which had to be removed by the fire brigade using heavy equipment in the vicinity of Heilbronn (Germany) today.

[Neomys Sapiens]

Do have a look at the Keysight app note and web calculator, its well explained there.

I'm probably being dense because I'm tired, but what Keysight app note?

He is probably referring to
5952-3706 Y-Factor Method for Noise Figure Measurement Accuracy
or
5952-8255 Fundamentals of RF and Microwave Noise Figure Measurements
or
5980-0288 10 Hints for Making Successful Noise Figure Measurements

That web calculator is probably the same as the enclosed excel-sheet. Can't attach it, too large.
Look for NFUC2017* at Keysight.

[Cerebus]

I christen thy not Penisfingers, but Peniseverything. Dickie for short.

Now we know where 'bd139' comes from, it's not a baby power transistor's part number, it's "Broken Dicky, 139 titanium pins in his bones".

[mnementh]

That scenery looks to me like a totally forlorn medieval hovel.    Sheep are stupid and clogging the drainage pipes.      Here you see a specimen which had to be removed by the fire brigade using heavy equipment in the vicinity of Heilbronn (Germany) today.   

So are children. You wouldn't blame a child who got similarly stuck, you'd blame whomever should have put/kept grates over the drains. 

I'd say... good thing that sheep found this dangerous drain first, rather than a child who would have PTSD for the rest of his/her life or worse. Digging up that infrastructure is a small price to pay for that lesson; a much smaller price than it COULD have been.

mnem
"Blaming the victim makes villains of us all."

[mnementh]

https://electronics360.globalspec.com/article/15393/next-generation-displays-may-be-powered-by-red-light-leds

One of the main reasons we have OLED displays right now is that this technological issue with red LEDs has till now stood in the way; getting adequate luminous flux from red micro-LEDs compared to that of green/blue on the same substrate has been a losing battle due to heat soak. This technology could put inorganic LED panels made similarly to OLED into production in just a few years, obsoleting OLED and its relatively short lifespan.

w00t! LCD panels could might maybe be dead, FINALLY!

mnem
 

[0culus]

@med...585A did great in another 6h+ burn-in session today. I'm declaring it fit for service...once the weather cools off. 

[Brumby]

Okay... who had 7/17/2020 in the "bd139 Recidivism" pool...? Was that you cub, or was it Brumby...? 

mnem
Not me... I missed it by at least 3 weeks.

Not sure if it was me - but I wouldn't feel right about claiming it anyhow, even if it was.

We all knew it was gonna happen.

[med6753]

@med...585A did great in another 6h+ burn-in session today. I'm declaring it fit for service...once the weather cools off. 

Good deal! 

Just do what I do.....crank up the A/C a few notches.