Re: VNA Resonance Methodology
If it helps add some confidence to this stuff, I used the air cored solenoid model in Genesys to predict the inductance and Q vs frequency for your coil. 49 turns 31mm diameter length 22mm wire diameter 0.4mm.
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This model in Genesys is typically quite good and I'm lucky to have access to CAD tools like this. Genesys predicts 65uH and a Q of 122 at 1.45 MHz as in the screen capture below.
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Although the red Q curve looks very similar to the Q curve in my earlier software plot (with a peak of just over 200 at about 7.5 MHz), I wouldn't trust either Q curve beyond about 80% of the way up the rising part of the curve. Above this I think both my software and the Genesys model will have creeping errors that could become very significant. Fortunately, you are operating down at just 1.45 MHz and I think the Q estimate of 122-124 across both tools should be fairly close to being correct.
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When making the coil for real, there will be uncertainties in the winding accuracy and the wire diameter and the enamel thickness of 'real' 0.4mm wire and these will introduce some uncertainty. Plus there will be some inaccuracy in the software tools (but I think not much down at 1.45 MHz in this case).
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Re: HP 6114A - looking for R8A, 15.82K 0.1% 1ppm resistor
I asked for the 1206 size as I only needed 1/8W and the price was less.
Here's the part ?
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Looks like I did get a followup email after declining moving forward saying "Let me ask manufacturing as maybe the unit price will be higher just for one."
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Dave
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Re: VNA Resonance Methodology
If I go with what you posted earlier I can assume that your current tank coil has 49 turns on a 31mm OD former using 0.4mm diameter wire (close wound) I can punch these numbers into the software program.?
For 0.4mm enamelled wire I usually assume about 0.06 to 0.08mm is added to the diameter of the wire because of the enamel coating. The enamel coating means the copper itself isn't perfectly close wound.
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So I've set the centre to centre gap of each winding at about 0.46mm in the software program.
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The software then predicts an inductance of about 66uH at 1.45 MHz and a Q of about 125. See the image below.
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This software is based on about 75 year old equations and lookup tables for inductance and Q factor etc. These old equations and tables have been proven many times by lots of people to be reasonably accurate.
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So I would expect your inductor to have an inductance of about 66uH and a Q of about 125 at 1.45 MHz. It shouldn't be far off these numbers unless the former you are using is adversely affecting the coil.
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A Q of 125 isn't that great. It should be possible to achieve a much higher Q if you use thicker wire and change the coil dimensions. This will end up having much larger dimensions than your current coil though. I can show you what I mean using the software if that helps?
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The alternative is to use Litz wire. Something like 160 strands of 48 gauge wire for example. This would give a much higher Q although it won't be cheap to buy Litz wire like this. It might double the Q compared to using a single strand of copper wire of equivalent diameter.
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Re: HP 6114A - looking for R8A, 15.82K 0.1% 1ppm resistor
That's surprising to me - I hope they're not changing their business model. I've been able to order single parts at my exactly specified value to two decimals before, on the Z201 variety. Is this what you asked for??
I suggest persisting. I can pull my records and see who you talked to vs. my contact (let's work on this offline, Dave). I stated to them I appreciate them doing this, which they responded to, so there's a conversation to reference.? Radu.?
I contacted TTC and the reality is less exciting than what their website suggests.? Their reply was "The MOQ for the series is 5 pc. since is a very peculiar R value."
Not sure why my 'any custom value from 250 to 25K' is special.
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Meanwhile I can find 5ppm parts of 15K and 820 ohm resistors in stock from Digikey for <$5 shipped, and really I just need to be in the range that A2R5 can adjust for so I could just use a single close value vs hitting 15.82K exactly.
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Re: HP 6114A - looking for R8A, 15.82K 0.1% 1ppm resistor
I contacted TTC and the reality is less exciting than what their website suggests.? Their reply was "The MOQ for the series is 5 pc. since is a very peculiar R value."
Not sure why my 'any custom value from 250 to 25K' is special.
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Meanwhile I can find 5ppm parts of 15K and 820 ohm resistors in stock from Digikey for <$5 shipped, and really I just need to be in the range that A2R5 can adjust for so I could just use a single close value vs hitting 15.82K exactly.
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Re: VNA Resonance Methodology
Hi jmr,
Well, it's an interesting methodology for sure. I do have a Nanovna which I bought purely for evaluation purposes, but I have two proper lab-grade HP VNAs as well. Can't recall the model numbers off hand but one's good to 1.3Ghz and the other to 6Ghz (expanded from 3). Unfortunately the matching S parameter test set? for the 6Ghz one tops-out at 3Ghz, however, which is a bit of a nuisance. Still, since we are only talking 1.4Mhz (virtually DC :-)) for this test, none of that fancy stuff is necessary anyway. :-)
Jinxie
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Re: VNA Resonance Methodology
Thanks, Froggie. By all means PM me when you have access to all your test equipment again.
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Re: Sticky ink of schematics
Personally, I have found that the laser printer at home doesn't
do this while the ones at work and in the print shop I use do ---
the difference may be that the one at home is black+white only and
is of the black powder toner+fuzer variety while the others are
colour and use a waxy sort of ink.
Luckily, when I needed some schematics printed on A3 I found a
print shop that had a black+white plotter that could go up to A0
and those haven't stuck to anything (yet).
I did at one point spray some colour prints with a clear lacquer
which seemed to work but a PITA.
As Ed says, Inkjet is the best alternative.
Dave
On 27/11/2024 06:26, ed breya wrote:
toggle quoted message
Show quoted text
Like Chuck said, laser printed items tend to stick to other
stuff over time. I haven't seen it too bad from one paper sheet
to another, but definitely from paper to plastics, or (toner
sides) face to face. I've seen and heard it (sounds like peeling
Velcro apart) especially from laser printed paper pages to
(inside) vinyl covers of 3-ring binders, and plastic page
separators and such, leaving some of the print transferred.
?
I think the best way to preserve paper documents is to laser
print one-sided only, and avoid any long term contact with
plastic materials - an extra blank paper cover sheet on top can
isolate it from a plastic layer. If it must be two-sided, go
with inkjet instead.
?
Ed
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Re: HP 8341B 1992 firmware version
That is correct, the firmware is the same for both. I have used exactly this firmware to update my 8341B without issues.
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Re: HP 8594E PSU repair/debug safety checklist
Hi Group check the power switch they tend to fail on those.
if the PSU is faulty contact me on OZ11LPR@... I have alot of parts for those units.
It is a pain to work on that powersupply type.
best regards Peter
Differential probe isn't going to keep *you* safe......? The isolation
transformer might.? (And most variac's are NOT isolation transformers)
On Tue, Nov 26, 2024 at 9:53?AM Ke-Fong Lin via groups.io
<anotherlin@...> wrote:
>
> Hi everyone,
>
> My HP8594E has a temperamental PSU, sometimes everything just works fine otherwise the SA just doesn't turn on.
> Something is obviously wrong and needs to be debugged.
>
> I've not opened the case yet. I've just searched a bit the internet ().
> HP doesn't provide schematics but people have already attempted repair.
>
> I may have to work on the "mains connected" (120VAC US or 220VAC Europe) side.
> So I just want to be sure that I would be safe with a differential probe, and if I use a diff probe, an isolation transformer wouldn't be needed.
>
> Seems that "curious marc" is using a variac as some form of isolation transformer:
>
>
> In general, do you guys have some links or checklists for safety when working on these kind of switch mode power supply.
> Thanks!
>
>
> Best regards,
>
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Re: Sticky ink of schematics
Like Chuck said, laser printed items tend to stick to other stuff over time. I haven't seen it too bad from one paper sheet to another, but definitely from paper to plastics, or (toner sides) face to face. I've seen and heard it (sounds like peeling Velcro apart) especially from laser printed paper pages to (inside) vinyl covers of 3-ring binders, and plastic page separators and such, leaving some of the print transferred.
?
I think the best way to preserve paper documents is to laser print one-sided only, and avoid any long term contact with plastic materials - an extra blank paper cover sheet on top can isolate it from a plastic layer. If it must be two-sided, go with inkjet instead.
?
Ed
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Re: HP 8341B 1992 firmware version
There is no differences in CPU board and firmware between 8340B and 8341B.
Calibration constants 79 and 98 must 2 for 8340B and 5 for 8341B, according to service manual.
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Re: VNA Resonance Methodology
Jinxie, I should return to the lab in a few weeks.
Can crank up my HP 4195A network -Spectrum analyzer (500 MHz)
Also the Boonton / Measurements GDO and Q meter
With a photo and specs of the coils you test, we can take a few tests.
Enjoy
Jon
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Re: VNA Resonance Methodology
OK..... quite a lot to digest there and it's rather late at night in my zone right now so I'll have to re-read this in the stark light of morning. I think it would be illustrative to post a photo of my current test set-up and reference plane. I suspect it might draw some healthy criticism from those of a particular disposition here, but no matter. I'm big enough to take a few insults. :)
If I forget overnight, feel free to remind me....
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Jinx.
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Re: Sticky ink of schematics
Modern laser printers and copiers use a finely powdered plastic toner to create the letters and pictures that are on the page. The plastic dust is placed onto the paper electrostatically, and is fused to the paper with very hot silicone rubber pinch roller. When you put such a printed sheet of paper into a vinyl binder, the same plasticizer that makes the vinyl soft and flexible will out gas and soften the plastic toner that is the printing on the paper. In my experience, you are screwed at this point. The plastic letters will be sticking to the adjacent sheet with the same vigor as they stick to the original sheet. -Chuck Harris On Mon, 25 Nov 2024 20:01:10 -0800 "Lexter Negron via groups.io" <lexternegron@...> wrote: Will do. An update, I found exactly what to call this courtesy of
someone from EEVblog. Was found thru searching "toner" in the old
threads.
/g/HP-Agilent-Keysight-equipment/topic/a_new_threat_to_the_hp_manual/24809333
/g/HP-Agilent-Keysight-equipment/topic/24809337
/g/HP-Agilent-Keysight-equipment/topic/24809401
I've currently stopped any separation on my part to see what options
I can take. Also I'm in the Houston area in Texas. Some of the stuff
was stored in a neighboring state. For the most part it gets hot and
humid but can get snow/frost. I suspect heating from many summers in
a warehouse did this.
-Lex
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Re: HP 8594E PSU repair/debug safety checklist
Don't get too enamored with tracing out and debugging your power supply, 9 times out of 10, the problem will be simply a case of bad electrolytic capacitors. I am not being casual with my statistics, this is hard won personal experience. The quickest way to "get'er'done", is to get an ESR meter, and check each electrolytic capacitor. Look exclusively for those that have ESR much greater than 1 ohm. When you find one, remove it, and measure its capacitance. Most of the time, it be low in an inverse relation to how high the ESR is. When you find a bad cap, replace ALL identical caps in the supply. Temperamental supplies are that way often because the electrolytic capacitors get worse when they are cold. For instance, a becoming very bad 100uf cap may be 25uf when hot, but only 2uf when cold. 25uf isn't great, but it may be enough to keep running, but 2uf isn't enough to start the supply (and warm up the cap). I do virtually all of my power supply debugging and repair with the power off, and no schematics. -Chuck Harris On Tue, 26 Nov 2024 06:53:47 -0800 "Ke-Fong Lin via groups.io" <anotherlin@...> wrote: Hi everyone,
My HP8594E has a temperamental PSU, sometimes everything just works
fine otherwise the SA just doesn't turn on. Something is obviously
wrong and needs to be debugged.
I've not opened the case yet. I've just searched a bit the internet (
). (
) ) HP
doesn't provide schematics but people have already attempted repair.
I may have to work on the "mains connected" (120VAC US or 220VAC
Europe) side. So I just want to be sure that I would be safe with a
differential probe, and if I use a diff probe, an isolation
transformer wouldn't be needed.
Seems that "curious marc" is using a variac as some form of isolation
transformer:
In general, do you guys have some links or checklists for safety when
working on these kind of switch mode power supply. Thanks!
Best regards,
|
Re: VNA Resonance Methodology
Note that the 6cm diameter loop antenna ideally needs to form a closed loop, so one end of the loop connects to the centre pin of the coaxial connector and the other end of the loop connects to the outer (ground) of the coaxial connector.
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Re: VNA Resonance Methodology
If it helps, I dug out one of my test solenoids and put a 390pF ATC 800B cap across it and used the loop antenna method to find the resonance with the VNA set to s11. See the image below where the resonance was at 1.945 MHz. If you use a modern synthesised VNA like this (even a nanovna), the proximity of the test resonator will not pull the frequency of the VNA. This is unlike a typical old school GDO where the GDO will lose its frequency calibration if you bring anything too close to the GDO's external coil as it will cause the GDO to change frequency.?
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In the example case below I could bring the loop antenna really close to the solenoid and the dip frequency did not change. Because the resonator capacitor is huge at 390pF it dominates any stray capacitance from the loop antenna. It's even possible to touch the solenoid and the loop antenna together and the dip stubbornly stays at the same frequency. But you can see that this isn't necessary as I got a decent dip with the setup in the image below.
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If I had fitted a variable capacitor it would be possible to watch the resonant frequency change in real time as the capacitance was changed. You can't do that with a GDO :)
There is no calibration performed on the VNA, it is running uncalibrated as it is only necessary to look for a dip with this method. You do have to set the VNA to 1dB/div or less. If using something like a nanovna I'd recommend using 0.2dB/div.
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You can see the loop antenna is just a loop of tinned copper wire with about a 6cm diameter. This is big enough to pass over the test coil with a good clearance. This method won't work so well for physically smaller solenoids and a different type of pickup loop may be required. It may even require a different test method. However, you are making a large air cored solenoid so this method should work really well :)
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Re: Troubleshooting a 8591e with opt 130
Marco, ? For A1-A5 and G1 to G3: +0.019V/ 1=+4.8V For G4 to G6:? -7.4V / +14.28V With my 8595E, A5 -16dB is activated with CORR=ON, and OFF when CORR=OFF. This would mean that I would probably have a similar problem if my A5 attenuator was not working, I would have a signal at -5dBm instead of -20dBm. ? I don't have the behavior you have, going from -9dBm to -10dBm. ? Yves
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Pulling CT2 Demodulator (opt 110) from HP8594E
I have a 8595E that I want to remove the CT2 Demodulator (option 110) card from.
Now I am wondering if any rewiring is required? I tried to find the option 110 installation
instructions, but sofar no luck.
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Any ideas?
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Wilko
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Jinxie
Froggie the Gremlin