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- HP-Agilent-Keysight-Equipment
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Re: 346B verification?
Hi Vladan, Thank you very much, That looks like it will answer every question one could ever dream up. I naively thought it would be much easier?to do. Dave VE7HR On Tue, Oct 22, 2024 at 11:35?PM pianovt via <pianovt=[email protected]> wrote:
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72 de Dave VE7HR |
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Re: 346B verification?
At Keysight, the noise source measurement bench uses two noise sources to calibrate the customer's noise source.
And of course the measuring bench in question includes the isolators as on the N2002A in order to guarantee the best possible accuracy.
For me and for many of the experts in this field, as VSWR is the biggest contributor to uncertainties in noise measurements, it is obvious that calibration without isolators is absolutely impossible. This can only be a check of proper operation, but in no way can this be called a calibration.
Even if it means paying, you might as well pay to get the most accurate values as possible.
Obviously Noisecom is certainly as precise as Keysight but I strongly advise against any other provider that is not seriously accredited. To determine which is the best, it is sufficient to request the technical annex of the accreditation in the field of noise measurements from the testing laboratory and to check whether the calibration uncertainties are satisfactory or not.
If the lab isn't accredited, then drop it, you'll pay for nothing.
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Re: Agilent Logic Analyzers 90-pin connectors
¿ªÔÆÌåÓýWasn't Digihouser a television show?DaveD KC0WJN Thanks for all the fish. ============================== All spelling mistakes are the responsibilty of the reader (Rick Renz, STK, ca. 1994) ============================== On Oct 23, 2024, at 04:29, Christian F1GWR via groups.io <f1gwr.groups@...> wrote:
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Re: Damaged HP feet
Eric, Glad my input helped! Once replaced, those will work as designed (non-slip, elevating the unit off the shelf for some convection, etc.) for a very long time (probably longer than the original due to likely better chemistry of the rubber today),?essentially equivalent to the original ones.? Radu.? On Wed, Oct 23, 2024 at 6:43?AM f1ghb via <f1ghb=[email protected]> wrote:
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Re: Damaged HP feet
Thanks Radu !
Following you message , I went to the Anchor Electronics web site and I have discovered the words "Square base (tapered) bumper" as in fact I was searching on the web with "square feet"
So then ,I found the 3M Grey Bumpon SJ5023? which seems the right one and available from Mouser at a good price
Thanks again
Best regards
Eric
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Re: Damaged HP feet
Eric, For this type? of feet - simple rubber blocks - I usually replace all four with generic ones. It's usually possible to find off the shelf ones that match very well, if not perfectly. I've found some that work really well at?places like Anchor Electronics and such.? Even if you'd find replacement ones in fair condition, they'd still be very old, and aged rubber will not last forever. If removed from an existing unit, I'm not sure how well they'd stick to yours.? Radu.? On Wed, Oct 23, 2024 at 5:33?AM f1ghb via <f1ghb=[email protected]> wrote:
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Damaged HP feet
Hello,
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On small HP power supplies ( E3630A ) I have a problem with the rear bottom rubber feet.
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With time , they become sticky , see pics with a nice one and three damaged.
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I am looking for spare feet or at least the HP reference of this type of foot to replace them ( I suppose they are just stuck on the case )
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The size is 21x21mm H=7mm , I have alreay found some but not with a height of 7mm
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Best regards
Eric |
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Re: HP 346A Noise Source Below 10 MHz
#file-notice
Arbitrary generator! You could generate any noise distribution you need in python and load it. Very long sequences are possible. Ref. Mersenne Twister and the like.? |
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Re: HP8555A BAND SWITCHING PROBLEM
Robert, I was wondering if it was one of those plastics impossible to glue. And, this raccords with your last comment Ed, at work we used a lot of polypropylene because it resists high temperatures and acids. That was polyfused which is exactly autogenous welding. Only with hot air, not flame of course. I thought first of trying that but the risk of my amateurish work destroying the minuscule piece discouraged me!
I also thought of machining one as you mentioned Ed. Still possible.
Thinking of the best course of action now!
Thanks,
Renaud |
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Re: HP8753B VNA question regarding if I purchase one
I don't think comparing the 8753 and nanoVNA can be an "apples-to-apples" situation. The 6GHz 8753 doubles the sweep signal and, presumably, filters it a bit to lower leak-through of the fundamental. The nanoVNA uses the third harmonic (or fifth for higher frequencies) and uses it in the presence of the larger fundamental, which is still there.?
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On the suggestion of learning to use VNA Cal Kit Manager 2, it does work on both Windows 10 and Windows 11. I have also recently used it on an older computer running Windows XP Service Pack 2. A very good place to start is Dr Kirkby's site? -, .?Lots of good reading to be found there. |
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Re: 346B verification?
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Show quoted text
On Oct 22, 2024, at 9:40?PM, pianovt via groups.io <pianovt@...> wrote:
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Re: 346B verification?
Gary, the most hobbyist-friendly approach would be to borrow a noise source with a trusted ENR table and use a noise figure meter to transfer the calibration to your noise source. That's in principle what Keysight does when you send your source in for calibration. There is a little bit of math involved which you can take care of in Excel.
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Keysight uses a noise figure meter, a noise source they vouch for, and a N2002A test set. They also check return loss before they calibrate the source. The N2002A is not essential, it helps automate the process. It contains some relays, attenuators and isolators.
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Vladan
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On Tue, Oct 22, 2024 at 08:03 AM, Gary Hitchner wrote:
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Re: 346B verification?
I do have some background information on this topic. George, you are incorrect. The 346 noise sources were designed at HP in Stanford Park (Palo Alto). As far as I know, they have never been made by an outside vendor. The only thing that changed since the original design is the fab that makes the noise diodes. HP obsoleted the Si process in Santa Rosa and started buying diodes from an outside fab. At least some of the founders of that outside fab were former HP employees.
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The N4000 noise sources were designed at Agilent U.K. in South Queensferry, as were NFA noise figure meters which are based on the E440X ESA economy spectrum analyzers.
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Noisecom made look-alike noise sources and even called them 346 to leave no doubt about what market they were after. There was another company, now called Noisewave, which made a similar product. I can't recall for sure, but Noisecom may have been started by a Noisewave employee after some disagreements. I also can't remember what Noisewave was called back then.
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Another manufacturer of noise sources was Ailtech, later part of Eaton, and after that Maury Microwave. Ailtech did not use the 346 designation. The Ailtech sources I opened didn't look anything like HP's. Some of them struck me as hobby projects. I think Maury gave up on noise sources. They now make calibration systems for noise sources.
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However, I just went to the Maury Microwave site and it appears that Noisecom is now part of them!
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Vladan
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Re: Repairing the Hp 2225a HP-IB InkJet printer
I bought a broken one to use for parts and one of the things I was
secretly hoping was that the flex circuit would be bad so I would have the excuse to rip it out and make a set of duplicate gerbers from a flatbed scan of it. On Tue, Oct 22, 2024 at 10:56?PM gren via groups.io <hrgerson@...> wrote:
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Repairing the Hp 2225a HP-IB InkJet printer
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The Hp 2225a ThinkJet InkJet printers are really very nice, compatible with many Hp instruments and provide easy screen/data printout directly from the instrument, often with the push of just one Hp button on the instrument.
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Much criticism of the 2225 has been directed at the "leaking" cartridge & corrosive ink.
-- But really this can be managed by removal of the cartridge (when not printing for long periods of time), storing it in a small
??????? Rubber? Maid type container, and periodic cleaning of spilled ink.
Otherwise, the Hp ThinkJet technology is superb, and a 1st for Hp of that era (ca. 1984).
( For fun, and amazement, read the Hp Journal May 1985 describing the development of the Hp ThinkJet, and peek at one of the developers stories in Hp Measure magazine, I will dig up that reference later ).
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Several frequent breakdown issues occur with the Hp 2225a HP-IB inkjet printer:
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A]
The Print Head electrode contacts frequently become corroded due to prolonged contact soaking in the corrosive Ink; where either the contacts themselves become corroded Or the contact-flex cable juncture develops a micro-crack, causing some of the 12 print head "character" nozzles? to not function ( non printing ).
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A1]
A repair can be had by following the excellent Repair Log "Fixing the ThinkJet" , by Martin Hepperle, September 2016.
( a .pdf is now in the Hp 2225 File Section herein ). One needs to buy an Hp Q7453a Carriage Assembly to do this.
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A2]
Flex head electrode cracks can be repaired with Silver (Ag) paint ( Silberleitlyck 3gm Art No.: 530042 ),
? as described in the below YouTube video
by atkelar:
? ? ?{ Note this YouTube provides a guide for complete disassembly & reassembly of the 2225a? HP-IB printer }
https://www.youtube.com/@atkelar
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B]
The Hp 2225 can fail to turn on Or suffer from a Mains power receptacle Rifa-type filter death (or short),?
which recently happened to me.? This repair is also covered, and rebuilt, by atkelar, in his YouTube video.
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PS recapping.? This also happened to my 2225a printer, & also covered by atkelar.
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Note:
? atkelar described using an older NOS 51604a Print cartridge, expired 5 yrs earlier,
printed well, with good results !
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TonyG?? has provided an excellent alternative Hp 2225a repair with a YouTube video swapping the whole front print section including the Carriage Assembly from a 2225 parts mule:
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Re: HP8555A BAND SWITCHING PROBLEM
Unfortunately, that's a very high stress zone, so any surface bond on the small cross section that's broken with adhesives or cements probably won't hold for long. Your best bet would be to find someone nearby junking out a 8555A that has the part available. If you want to rebuild it, glue it back together to original shape, then study the mechanics of the pieces and operation, and figure out where you can add reinforcing elements to beef it up in the high stress parts. You can add whatever you want as long as it doesn't interfere with the action.
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If you have access to machine tools, another option is to build a copy in metal, like zinc alloy (pot metal) or aluminum block. With zinc you can even make a rough casting to start, with fairly simple mini-foundry stuff you can build.
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I've junked out several 8555As many years ago, so I remember sort of what's inside those lever assemblies, but don't recall if I had saved any of them.
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Good luck.
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ED |
Christian F1GWR
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