Not exactly on the bench, but the bench itself finally rearranged to start on the next project(s) Still some work left organizing the fiddly bits though...
No, we are certainly not alone in the addiction and I can see that you've fallen in the RF money pit as well - it's not the equipment, it's the fiddly bits to make it work that will endanger your bank balance.
Believe me Hal, it's the RF equipment! The little bits don't help on bit for sure.
I just looked at an HP 8657A (I'd like one) and they are still pretty dear. I'd like a working Panasonic VP-8131A (or very similar), the one I bought from a trusted dealer doesn't work.
The RF game is a very expensive one, and prices rocket up as frequencies increase. Low noise audio is no joke either.
I just looked at an HP 8657A (I'd like one) and they are still pretty dear. I'd like a working Panasonic VP-8131A (or very similar), the one I bought from a trusted dealer doesn't work.
The RF game is a very expensive one, and prices rocket up as frequencies increase. Low noise audio is no joke either.
I suppose that my big gear/little stuff costs are skewed a little - the high end RF gear that I have that I purchased used I got for very good prices - most of it purchased four or five years ago or so when there was a glut of it coming available. As I primarily use it to calibrate other equipment to absolute values I tend to put more money into verifiable quality adapters, attenuators, cables and such than might otherwise be the case. Worked on a large project for the Corps a few years back characterizing cases of gear at up to 20 GHz or so and really learned a lot about how the difference in quality of the peripherals matters - just a series adapter was 500-600 USD and a 1 meter cable easily ran 5K or more. Of course I don't need that level of performance for what I do, but even down around 3 or 4 GHz it makes a significant difference when you are worrying about a few tenths of a dB. Personally, I'm really wanting to get away from that type of thing and get back down in the weeds of under 100MHz or so (DC, yea!!)
Well yes. Lab quality cables are not only very expensive as you've noted, but they are also consumables. Adapters, combiners and other RF gear is breathtakingly expensive. Not to mention calibration kits. I use "N" and "BNC" (low frequency stuff). The APC kit, ouch!
Heck, my Kelvin leads for the HP 4263A was about $600 when I bought that meter new in the 1980's. My scope probes are only $270 each (500 MHz - Keysight). Look at the prices of active probes today.
Heck, my Kelvin leads for the HP 4263A was about $600 when I bought that meter new in the 1980's. My scope probes are only $270 each (500 MHz - Keysight). Look at the prices of active probes today.
Just a tip - as long as the Kelvin clips themselves are decent, just about any DIY cable will work as long as the standard acclimation time is given and you do a null. I have several sets of 4-wire cables where the force/sense wires are combined in the termination - a set I just made last week uses 12GA for the force wires, 18GA for the sense terminated in large gold plated spade lugs to test those resistance boxes I was working on. Unless you are measuring significant currents that extra 1/2" of heavy shared copper won't make any measurable difference. I have several rolls of good silicone test lead wire in various sizes and colors and just make leads or jumpers if I need them. If you are really going down in the weeds with your measurements then pay attention to temperature gradients to minimize thermoelectric offsets and Seebeck voltages in the test setup.
Hi Hal,
Very true on all counts. I make my own leads often enough, give me Kelvin clips and I'll build them, although you only need two sets of banana to clips for the same connections with direct current. At higher frequencies the position of conductors in relation to each other can matter. Always short - open compensation.
I bought those with the meter back when the 4263A was first introduced. I was young and figured I should use the recommended lead sets. Not a bad way to go if you know only the theory. Just out of Ryerson then (a couple years). Today I use DIY leads for anything like that at DC. I almost never need high current connections. You probably didn't need 12 ga leads for the current source leads depending on the currents involved. But, why not? The sense leads could have even been 22 ga stranded copper. In the lab we used terminals, similar to spade connectors. Tellurium copper of course (as we were certifying equipment).
Very true on all counts. I make my own leads often enough, give me Kelvin clips and I'll build them, although you only need two sets of banana to clips for the same connections with direct current. At higher frequencies the position of conductors in relation to each other can matter. Always short - open compensation.
I bought those with the meter back when the 4263A was first introduced. I was young and figured I should use the recommended lead sets. Not a bad way to go if you know only the theory. Just out of Ryerson then (a couple years). Today I use DIY leads for anything like that at DC. I almost never need high current connections. You probably didn't need 12 ga leads for the current source leads depending on the currents involved. But, why not? The sense leads could have even been 22 ga stranded copper. In the lab we used terminals, similar to spade connectors. Tellurium copper of course (as we were certifying equipment).
Re the wire size - they are large enough for current measurement as well and the wire, while of a larger gauge, is flexible enough to still be easy to use. I would like to find a source of really good spade connectors made with metrology in mind - banana jacks and plugs are easy but I haven't found anything I trust (not made of Chinesium) to buy.
As for other cables, I made a set of jumpers to go from the Wayne-Kerr non-standard spacing to the standard HP LCR test fixtures using 1' RG316 cables. Speaking of RG316, it's actually pretty useful and performs very well for a lot of uses - I get the inexpensive jumpers off of ePay and test them on the SA when I get them; very few have had issues, surprisingly.. It's what I use for the 10MHz standard distribution to everything and also for general purpose use. A unterminated spool makes for a good source of shielded hook up wire as well.
Lol!
Absolutely with you there Hal!
Banana connectors aren't what I would call reliable or repeatable from a connection resistance standpoint. Only clean spade connectors are. Straight copper beats plated mystery connectors. That's why lab meters have binding posts. Banana plugs are only good for connections where current draw is low and voltage drop isn't significant. For anything where emf due to temperature - material issue exist, straight copper spade connections.
Absolutely with you there Hal!
Banana connectors aren't what I would call reliable or repeatable from a connection resistance standpoint. Only clean spade connectors are. Straight copper beats plated mystery connectors. That's why lab meters have binding posts. Banana plugs are only good for connections where current draw is low and voltage drop isn't significant. For anything where emf due to temperature - material issue exist, straight copper spade connections.
At least I haven't had to make spacing adapters - yet.
I use 316 or similar and keep it on hand. If I need a shielded run for audio - I use that. Wonderful stuff. I used 58uc for 10 MHz distribution. It is a little stiff for test leads.
I use 316 or similar and keep it on hand. If I need a shielded run for audio - I use that. Wonderful stuff. I used 58uc for 10 MHz distribution. It is a little stiff for test leads.
So this scenario from one who has learned this lesson the hard way in the past but let his inner dumbass overrule experience:
Just started working on a recent acquisition, a Fluke 343A voltage standard... have the cover open, using thermal camera to check for hot spots... sees one, uses finger to highlight component that is hot... in 1KV HV section... (re)discovered that cooking human flesh does, indeed, smell somewhat like pork... arc flashes do, at least, cauterize holes blown into the heel of one's palm... the lesson does not get any less painful the more times that it is learnt... spouse's (quite accurate) comments ensure any remaining shreds of my ego are fully shredded.
Sigh. Think I've had enough fun for one day 😢 and am going to go play with the puppies.
Hal
Just started working on a recent acquisition, a Fluke 343A voltage standard... have the cover open, using thermal camera to check for hot spots... sees one, uses finger to highlight component that is hot... in 1KV HV section... (re)discovered that cooking human flesh does, indeed, smell somewhat like pork... arc flashes do, at least, cauterize holes blown into the heel of one's palm... the lesson does not get any less painful the more times that it is learnt... spouse's (quite accurate) comments ensure any remaining shreds of my ego are fully shredded.
Sigh. Think I've had enough fun for one day 😢 and am going to go play with the puppies.
Hal
Hi Hal,
I'm very glad you're okay. Knowing this ... LMAO! I've done similar things so many times. Do we ever learn?
Yes to all your observations, HV effectively punches holes in skin and is kind enough to seal the wound so you don't bleed all over the place.
Yeah, it's time to go play with the dogs and hopefully your spouse takes pity upon you at some point. Do take care of the hand, it's going to sting-hurt (or whatever that sensation is).
I'm very glad you're okay. Knowing this ... LMAO! I've done similar things so many times. Do we ever learn?
Yes to all your observations, HV effectively punches holes in skin and is kind enough to seal the wound so you don't bleed all over the place.
Yeah, it's time to go play with the dogs and hopefully your spouse takes pity upon you at some point. Do take care of the hand, it's going to sting-hurt (or whatever that sensation is).
I suggest a gift for your housemate…
https://www.calmedequipment.com/pro...WLSLUc3b9TVoC_AuG_vg_XmVN4bS58ChoCvFUQAvD_BwE
https://www.calmedequipment.com/pro...WLSLUc3b9TVoC_AuG_vg_XmVN4bS58ChoCvFUQAvD_BwE
That would be over $2K here - lol! Thanks though.
Maybe I'll just teach her how to set my HV supply and current limit. She can hit me with existing equipment. lol!
By the time anyone got here, I'd be long gone. Plus when Jovanka is here, I tend to play hooky from the bench and spend my time with her. Yup, it's true. She's the first woman who has broken the workaholic. Believe it or not.
Maybe I'll just teach her how to set my HV supply and current limit. She can hit me with existing equipment. lol!
By the time anyone got here, I'd be long gone. Plus when Jovanka is here, I tend to play hooky from the bench and spend my time with her. Yup, it's true. She's the first woman who has broken the workaholic. Believe it or not.
It's what happens when you combine exhaustion with something dangerous - there is a reason that is at the top of just about every "Don't Do" list. In the end I was very lucky that I was reminded of this with no more than a band-aid and embarrassment as consequences.
Another 343A - no electrocutions this time around 😏
This one needed the chopper amplifier adjusted and "finicky" doesn't even begin to describe it. The manual makes it sound like a very easy process - and maybe on some units it is - but on this one the balancing act adjusting R160 and R162 took most of the morning. The unit wouldn't let you get the Zero Adjust better than -8 uV at the end of the adjustment range and it should be able to get better than +- 2uV somewhere in the middle. Anyway, it's done and it adjusted fully within factory specifications in the end. And, most importantly, did I mention no electrocutions?
This one needed the chopper amplifier adjusted and "finicky" doesn't even begin to describe it. The manual makes it sound like a very easy process - and maybe on some units it is - but on this one the balancing act adjusting R160 and R162 took most of the morning. The unit wouldn't let you get the Zero Adjust better than -8 uV at the end of the adjustment range and it should be able to get better than +- 2uV somewhere in the middle. Anyway, it's done and it adjusted fully within factory specifications in the end. And, most importantly, did I mention no electrocutions?