Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

Wake up this morning to a temperature of -2 C and freezing rain. That's rain that falls as liquid and then immediately freezes upon hitting the ground. Turns everything including the roads into a sheet of ice. The scanner is going nuts with numerous accidents. Road crews are out sanding/salting but naturally can't be everywhere at once.

It's becoming a real clusterfuck out there.  Glad I don't have to go anywhere. It is supposed to go above freezing later today.

Edit....call just came across....even the salt trucks are getting into accidents. 

They were calling for the same here as it went down to -10°C overnight. Luckily, so far no rain in my neighborhood even tho it was in the forecast, and temps are climbing towards positive numbers rapidly as the sun rises.

As we have to park in the street until the ToD is gone, such things are a multiple-point source of worry.

mnem
There is no shortage of unfit drivers in any locale.

[mnementh]

Bandwidth is indirectly affected by the cable / connector construction. The mechanical dimensions plus the dielectric properties of the insulator determine the nominal impedance. The properties of the material (wire and dielectric), especially dielectric and resistive losses, determine the damping of the cable. Usually damping increases with increasing frequency, so "better materials" and construction details have large influence on the resulting bandwidth and damping of a cable. This is more difficult to achieve as the frequency increases.
As far as I remember, a 60Ohm impedance cable, using common (non-expensive) material can achieve the best damping performance, due to some lucky coincidences in construction details (ratio of inner core / shield diameter and amount of used dielectric). High power cables often use air as dielectric and as little as possible non-air material to keep the inner conductor centered in the shield.

Not sure what you mean by "bandwidth". It's not a normal coxial cable parameter.

Fully agreed, this isn't a normal cable parameter, and I agree to your further explanations.

I thought of explaining through a very simplified model, why the "thicker" cable might have more "bandwidth" than the "thinner" cable for maybe sub 2GHz applications. Here you've got to deal mostly with increasing damping over frequency, and this could be simplified seen as "the better cable has more bandwidth". Next issue would be losses and distortion due to impedance mismatch, this for sure is valid for some 10MHz and above, depending on cable length.

I think part of the confusion here arises when comparing against commercially produced patches which are often advertised as sweep tested to a certain minimum frequency.

Obviously cables made in-house are going to respond in ways that you cannot 100% predict without doing similar testing after fab; even resonant length between two otherwise identically fabbed cables will play a factor.

I've always taken such "sweep-testing" claims with a grain of salt big enough to pickle a dwagon; the "affordable" ones seem to rarely refer to any specific test specification.

mnem
 

[med6753]

I'm getting very adept at putting the Type 547 on it's side without killing myself. But I must avoid getting over confident. 

The Type 1A1 will be done first then the Type 1A4. More later.

[xrunner]

Some flakiness (a technical term) reared it's head on the Boonton power meter. Something is not making good contact and when I tap around the chopper assembly it seems to indicate it's around that area.

The chopper is in a socket but when I tried to pull it out it wouldn't budge. I had to disassemble the front panel again so I could grip it better. I was then able to pull it out of the socket but it was damn difficult. May have never been removed since Day One. Oh interesting what is the black powder down there? 

Looking around for issues I noticed that one - and only one - transistor in the entire unit is in a socket: Q107. I pulled it and re-seated it.

[Martin Miranda]

  it really feels that i'll be taking an exams. and the service manual looked like really a big old power point presentation. 

[med6753]

Flakiness is a technical term I accept and use often. 

[mnementh]

Hey... has anyone here noticed that eevBlog/SMF seems to render YT vids in a larger size by default now? I thought I remembered it rendering to 640px wide; now it seems to render to ~1024px wide...?   

I find that as annoying as some of you find my "colorful speech"

Does eevBlog/SMF support any kind of video tags yet? I remember the last time I tried to use html embed code it just interpreted it as plaintext... 

mnem

[mnementh]

Flakiness is a technical term I accept and use often. 

Yup... along with percussive maintenance, empirical engineering, and ambiguous specifications.  Oh, and booty-fab.

mnem
*casts his gaze about the bench for his rotary embiggener*

[mnementh]

   ...Oh interesting what is the black powder down there? 

   What I see on the surface of the socket insulator looks to be an imprint from a rubber seal or label. Other than that, maybe a bit of tarnish on silver-plated connector pins/sockets...?

mnem

[mnementh]

mnem

[TERRA Operative]

So, to calibrate and adjust the SG505 Oscillator, I need to restore and adjust and calibrate an AM502 differential amplifier, and to do that I need to build an RC normalizer.

I built one before so it's no big deal to build another, but can someone tell me where the rabbithole ends???     

[mnementh]

...can someone tell me where the rabbithole ends???     

When you pop out the other side of the planet... in your case Brazil, I believe. 

mnem
Then of course, you have to rabbit-hole back home... 

[SilverSolder]

Wake up this morning to a temperature of -2 C and freezing rain. That's rain that falls as liquid and then immediately freezes upon hitting the ground. Turns everything including the roads into a sheet of ice. The scanner is going nuts with numerous accidents. Road crews are out sanding/salting but naturally can't be everywhere at once.

It's becoming a real clusterfuck out there.  Glad I don't have to go anywhere. It is supposed to go above freezing later today.

Edit....call just came across....even the salt trucks are getting into accidents. 

I remember driving along back roads during one of these freezing rain storms.  I felt things were getting too slippery to drive any further, and stopped the car.  At the place I stopped, the road was so slippery that the crown in the road was enough to make the car slowly slide sideways even while standing still!   

[BU508A]

I remember driving along back roads during one of these freezing rain storms.  I felt things were getting too slippery to drive any further, and stopped the car.  At the place I stopped, the road was so slippery that the crown in the road was enough to make the car slowly slide sideways even while standing still!   

Reminds me of this:

https://youtu.be/iUODdPpnxcA

 

[Specmaster]

I'm getting very adept at putting the Type 547 on it's side without killing myself. But I must avoid getting over confident. 

The Type 1A1 will be done first then the Type 1A4. More later.

Yay, please take care when moving those about, we don't a repeat performance do we

[Cerebus]

Just finished to watch "don't look up" movie.
Excellent.

Is that the title of the movie, or an instruction implying that you'll pollute your search history forever if you do look it up? 

[Cerebus]

It is a standing joke that the letters to newspapers and other periodicals from nutters are written ALL IN CAPITALS IN GREEN INK. I can tell you from my personal experience of actually sitting, opening and reading the correspondence to periodicals that those kind of formatting quirks are pretty reliable indicators that the correspondent is going to be somewhere on the spectrum from "incoherent monomaniac" to "Erm, I think we'd better call the police". The quirk wasn't always ALL IN CAPITALS IN GREEN INK but it genuinely made up the higher proportion of crank letters than did other creative and unconventional approaches to formatting.

Plus ça change, plus c'est la même chose.

I've always been guided by “Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” ― Antoine de Saint-Exupéry, Airman's Odyssey

Have you ever tried to find Saint-Exupéry in a bookshop or a library on the physical shelves? Booksellers and librarians sometimes shelve him under "D", sometimes under "S" and I've even found them shelved under "E". Frustrating...

P.S. If you like Saint-Exupéry you'll probably also like Russell Hoban. There is no good literary reason for this, but I've found that people who like one ofttimes also like the other.

[Cerebus]

Wake up this morning to a temperature of -2 C and freezing rain. That's rain that falls as liquid and then immediately freezes upon hitting the ground. Turns everything including the roads into a sheet of ice. The scanner is going nuts with numerous accidents. Road crews are out sanding/salting but naturally can't be everywhere at once.

It's becoming a real clusterfuck out there.  Glad I don't have to go anywhere. It is supposed to go above freezing later today.

Edit....call just came across....even the salt trucks are getting into accidents. 

I remember driving along back roads during one of these freezing rain storms.  I felt things were getting too slippery to drive any further, and stopped the car.  At the place I stopped, the road was so slippery that the crown in the road was enough to make the car slowly slide sideways even while standing still!   

I'm confident enough in my driving ability and my ability to modify how I drive according to the road conditions that I'm prepared to go out driving in almost any weather, with the following provisos:

• It not so windy that you're likely to get picked up and flung about.
• The number of other drivers on the road is small enough that my chances of encountering someone who can't adapt to the weather are acceptably small.
• The weather is not freezing rain. If it is I either don't go out, or park up until it is safe. Horrible stuff, truly, truly, horrible.

[mansaxel]

Cooking with TE:

[ Specified attachment is not available ]

[med6753]

Wake up this morning to a temperature of -2 C and freezing rain. That's rain that falls as liquid and then immediately freezes upon hitting the ground. Turns everything including the roads into a sheet of ice. The scanner is going nuts with numerous accidents. Road crews are out sanding/salting but naturally can't be everywhere at once.

It's becoming a real clusterfuck out there.  Glad I don't have to go anywhere. It is supposed to go above freezing later today.

Edit....call just came across....even the salt trucks are getting into accidents. 

I remember driving along back roads during one of these freezing rain storms.  I felt things were getting too slippery to drive any further, and stopped the car.  At the place I stopped, the road was so slippery that the crown in the road was enough to make the car slowly slide sideways even while standing still!   

I'm confident enough in my driving ability and my ability to modify how I drive according to the road conditions that I'm prepared to go out driving in almost any weather, with the following provisos:

• It not so windy that you're likely to get picked up and flung about.
• The number of other drivers on the road is small enough that my chances of encountering someone who can't adapt to the weather are acceptably small.
• The weather is not freezing rain. If it is I either don't go out, or park up until it is safe. Horrible stuff, truly, truly, horrible.

Agree 100%. And driving in snow takes an extra acuteness acquired from years of experience. Your hands on the steering and the feel coming up from the seat into your arse can give you fair warning that you are approaching the limits of control. And some features on new vehicles can be a hinder that rather than help.

AWD or 4WD is a definite plus.
If you have an automatic disable OD.
Snow or good all season tires.
ABS is 50/50 like/dislike.
I turn OFF traction control. I experimented with it and I do NOT like how it reduces power. Sometimes you WANT wheel spin.     

[AVGresponding]

So, to calibrate and adjust the SG505 Oscillator, I need to restore and adjust and calibrate an AM502 differential amplifier, and to do that I need to build an RC normalizer.

I built one before so it's no big deal to build another, but can someone tell me where the rabbithole ends???     

This rabbit hole is the shape of a Klein bottle. Hope that helps.  https://en.wikipedia.org/wiki/Klein_bottle

[Cerebus]

Agree 100%. And driving in snow takes an extra acuteness acquired from years of experience. Your hands on the steering and the feel coming up from the seat into your arse can give you fair warning that you are approaching the limits of control. And some features on new vehicles can be a hinder that rather than help.

AWD or 4WD is a definite plus.
If you have an automatic disable OD.
Snow or good all season tires.
ABS is 50/50 like/dislike.
I turn OFF traction control. I experimented with it and I do NOT like how it reduces power. Sometimes you WANT wheel spin.     

I think that in snow all those driver assist features can be a hinderance. Yes, they may keep you out of trouble sometimes, but what they won't do is let you learn to feel where the edge of control is by the seat of your pants. Feeling minor losses of control in snow teaches you to back off and become more progressive in everything you do until you've learned to stay inside the envelope where everything does stay in control.

Like you I'm 50/50 on ABS - a good one like I have on my current car will provide some feedback without snatching control away, a bad one like I had on my late 80s vintage Honda Prelude will let go of the brakes entirely when it's on a surface where some slip is inevitable. With the Honda one, if you were driving on gravel you had no brakes at all and had to get any stopping power from engine braking. I discovered that 'feature' on driveways, I'm glad I didn't find it out on a gravel filled escape lane on a hill.

[0culus]

Wake up this morning to a temperature of -2 C and freezing rain. That's rain that falls as liquid and then immediately freezes upon hitting the ground. Turns everything including the roads into a sheet of ice. The scanner is going nuts with numerous accidents. Road crews are out sanding/salting but naturally can't be everywhere at once.

It's becoming a real clusterfuck out there.  Glad I don't have to go anywhere. It is supposed to go above freezing later today.

Edit....call just came across....even the salt trucks are getting into accidents. 

I remember driving along back roads during one of these freezing rain storms.  I felt things were getting too slippery to drive any further, and stopped the car.  At the place I stopped, the road was so slippery that the crown in the road was enough to make the car slowly slide sideways even while standing still!   

I'm confident enough in my driving ability and my ability to modify how I drive according to the road conditions that I'm prepared to go out driving in almost any weather, with the following provisos:

• It not so windy that you're likely to get picked up and flung about.
• The number of other drivers on the road is small enough that my chances of encountering someone who can't adapt to the weather are acceptably small.
• The weather is not freezing rain. If it is I either don't go out, or park up until it is safe. Horrible stuff, truly, truly, horrible.

Agree 100%. And driving in snow takes an extra acuteness acquired from years of experience. Your hands on the steering and the feel coming up from the seat into your arse can give you fair warning that you are approaching the limits of control. And some features on new vehicles can be a hinder that rather than help.

AWD or 4WD is a definite plus.
If you have an automatic disable OD.
Snow or good all season tires.
ABS is 50/50 like/dislike.
I turn OFF traction control. I experimented with it and I do NOT like how it reduces power. Sometimes you WANT wheel spin.     

Depends on the traction control. My 4Runner has multiple traction control modes that are specifically designed for off road use, and you can tune how much wheelspin it will allow depending on the surface. It's also a proper 4x4 with low range though...low slung crossovers with AWD are substantially less than optimal if you encounter real snow because you'll start pretending to be a snow plow a lot sooner....and you won't make much forward progress. I will also say there is a reason studded tires are legal in locales that get significant winter.

[mansaxel]

So, to calibrate and adjust the SG505 Oscillator, I need to restore and adjust and calibrate an AM502 differential amplifier, and to do that I need to build an RC normalizer.

I built one before so it's no big deal to build another, but can someone tell me where the rabbithole ends???     

I also have a SG505, albeit with Options 1 & 2. (IMD output and Balanced output). At a minimum I need to build myself a 600Ω termination; unterminated  output is way high. This also was very obvious as I used my telephone transmission tester; which suffers from the same problem.

[mansaxel]

Like you I'm 50/50 on ABS - a good one like I have on my current car will provide some feedback without snatching control away, a bad one like I had on my late 80s vintage Honda Prelude will let go of the brakes entirely when it's on a surface where some slip is inevitable. With the Honda one, if you were driving on gravel you had no brakes at all and had to get any stopping power from engine braking. I discovered that 'feature' on driveways, I'm glad I didn't find it out on a gravel filled escape lane on a hill.

Previous Volvos were FWD and their traction control is excellent. So good it is boring. Their ABS works too, on most surfaces.  Present Volvo is AWD, and I have yet to get a wheelslip serious enough that the traction control wanted to interfere.