nice DVM

Joerg wrote in news:32ZIi.10212$z snipped-for-privacy@nlpi069.nbdc.sbc.com:

but only 3% accurate,IIRC. and -analog- display. The 34401A is 1000x more accurate.

Best regards, Spehro Pefhany

The 34401A had the display digits, down into the nV, but the last few were mostly random numbers. The VF display kicked huge spikes out the input terminals. Instead of fixing it, they mucked the firmware to make AC readings drop to zero somewhere not too far south of 1 mV. And I always found the menus confusing.

John

And that is supposed to mean that Fluke is not?? 30 years ago when i worked in the Cal lab at Ford Aero Space, we received 20 Fluke bench DVMs (do not remember model number) for incoming inspection, and they all were within one-tenth of the datasheet spec! And they did not change much the next two years. That is to say, they could have been used as secondary standards.

The Fluke is speced to 6.5 digits, has better resolution, has more ranges, etc than the Keithley meter. I did not check the AC specs between the meters, but i think that

Robert Baer wrote in news: snipped-for-privacy@corp.supernews.com:

What did I say to have you think that? When I said "Keithley is a reputable company.",I meant that they support their products,even those made for them in Taiwan.They've been around for a LONG time,too.

So,what did YOU mean with "You get what you pay for..." ?? Are you implying that Kiethley is NOT a reputable company?

And that was THIRTY YEARS AGO. Fluke is certainly not the same company today. HP isn't,nor Tektronix.

But a staunch 5kV spike out of a defibrillator test rack can be like death to a DVM while the VTVM doesn't even flinch.

Well, like the doctor said, don't do that!

John

Sometimes s..t happens. Just had that in the lab. Transistor croaked for no apparent reason and, whaddabam, three instruments are toast. Will be repaired but not today since the missus wants me to tune the piano first. She'll treat me to my favorite dish tonight, Rouladen. That kind of sealed the deal.

I think that Fluke has been around for a long time also, so neglecting one company by mentioning a different one does seem to "diss"...

The price of the Kiethley meter is a fair amount less than the price for the Fluke meter - and what one gets (ranges and resolution) is a lot less for the Kiethley WRT the Fluke meter. So..you get what you pay for.

Good old Shakespeare..does not quit. Tubes may have a little glow at high voltage, but robust as all heck. And it takes a hell of a lot of RF to swamp them, but not much to kill operations of semiconductor products.

Modern switchers are a LOT less "noisy" Than they were back in the days when you were taught that they were far "more noisy".

modern switchers, like everything else, tend to be optimised for minimum cost. 3dB below the EMC limits is good enough. 6dB is massive overkill. Sad, but true.

Cheers Terry

We use switcher warts for all our digital delay generators and fiberoptic gadgets, and get jitters in the single digits of picoseconds. It's not all that many dB separating switcher noise from all the other crud floating around these days.

John

OK, let's take your VTVM, and my handheld Fluke, and drop them from equal heights onto a hard floor.

I had an Eico 221 when I was a kid, built from a kit, $26 from Allied. All the really cool kids had Eico's, and the jerks bought Heathkits or, horrors, RCA.

John

Sure but that becomes a nightmare when you have to hold laser diodes stable to tens of femtometers. Luckily it's not as bad as in S.F. here although one client resides near an unmarked building with lots of shortwave antennas on top. That had caused some grief when measuring stuff. The good thing is most people use spread spectrum these days so the noise can be dealt with easier. Another client is next to a busy runway. That'll be a challenge in a few weeks so I'll be staying the weekend hoping it'll be less busy with freighters and all that.

I meant electrically. I wonder what your Fluke would say if a defibrillator jolt accidentally arced over into the probes. Euro strength, meaning 5kV out of a 32uF cap via some inductors. I have seen innocent looking electronics explode when that happened.

My Heathkit dipmeter holds up pretty well, around 30 years now. Ok, their overall quality wasn't quite up to par with Eico IMHO. Except on ham radio transceivers and stuff, those were very sturdy.

Sounds like the typical big-company scenario where most of all the good technical people are long gone, but the name still holds marketing value, so they contract out to the lowest bidder to build new devices with little idea of whether or not what they're getting is junk.

Hey, my new Aeroflex spectrum analyzer has a tracking generator. So maybe I can cobble up some little box with two connectors and a loop, so if I hold it near something I can see a sweep of the interaction with the loop. That would become a high-res sweeping grid-dip meter. It could look for all sorts of resonances in all sorts of structures - pc boards, cable harnesses, enclosures - not just coils.

John

I've tried that with my network analyzer. Basically works but not even close to the sensitivity of a dipmeter.