hybridfree/eevblog-posts huggingface dataset:
Video: homebrew fun with a Michigan Mighty Mite - Page 1
Forum section: electronics / rf-microwave

author: w2aew
author_rank: Super Contributor
timestamp: January 27, 2016, 05:13:23 pm
content: ...and why a low pass filter is needed.

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 27, 2016, 07:56:45 pm
content: Would it be interesting to find out where the distortion came from? It should not be so hard to get an output that looks a bit more like a sinus to begin with...

author: w2aew
author_rank: Super Contributor
timestamp: January 27, 2016, 09:57:41 pm
content: Quote from: PA0PBZ on January 27, 2016, 07:56:45 pmThe distortion isn't surprising from such a minimalist oscillator/driver. Of course there are much cleaner oscillator circuits out there, but my intention was to show the performance of this design because it is so popular in the QRP world.
Want to take a guess at what radio is used here? - Page 1
Forum section: electronics / rf-microwave

author: HSPalm
author_rank: Regular Contributor
timestamp: January 21, 2016, 09:30:13 am
content: Came across these and find them interesting. Not because I want them, but I wonder what type of radio they might use. No frequency specified.http://www.banggood.com/Wireless-Smart-iOSAndroid-APP-Lamp-Controller-1-Gang-220V-For-Home-p-1031373.htmlhttp://www.banggood.com/Wireless-Smart-iOSAndroid-APP-Lamp-Controller-2-Gangs-220V-For-Home-p-1031347.htmlhttp://www.banggood.com/Wireless-Smart-iOSAndroid-APP-Lamp-Controller-3-Gangs-220V-For-Home-p-1031346.htmlThey claim "no bluetooth or wifi needed", but you can control them from your smartphone. They also claim a range of 10 meters. If I get to curious I might buy one, but not sure I bother.

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 21, 2016, 10:27:01 am
content: Audio? Sure looks like a speaker symbol in one of the pictures.

author: HSPalm
author_rank: Regular Contributor
timestamp: January 21, 2016, 10:53:55 am
content: Sure does... Looks like a vertically mounted radio module on there though. Could of course be audio reception and processing. They say you can turn off your lights from outside after you closed the door behind you, would not be easily done with an audio signal I think.

author: coppice
author_rank: Super Contributor
timestamp: January 21, 2016, 06:29:59 pm
content: Those are acoustic. The white plastic bobble on short leads contains an electret mic. However, I don't know what kind of acoustic signal is sent. The people who make these also make bluetooth lighting gadgets controllable from an Android phone or iphone app, but the units you referenced are definitely the acoustic type.

author: HSPalm
author_rank: Regular Contributor
timestamp: January 22, 2016, 09:16:26 am
content: I actually never noticed that white bobble hanging off there. Thanks guys, guess the mystery (to me) is solved

author: cdev
author_rank: Super Contributor
timestamp: January 23, 2016, 05:51:53 am
content: "the Clapper" anybody in the US remember that ad?https://en.wikipedia.org/wiki/The_Clapper

author: coppice
author_rank: Super Contributor
timestamp: January 23, 2016, 06:30:56 am
content: Quote from: cdev on January 23, 2016, 05:51:53 amA lot of early remote control TVs simply listened for 40kHz sound bursts to step through the channels. The fancier transmitters had batteries. The simpler ones just had a metal rod that was wacked when you pushed a button. The rod resonated at 40kHz, and the channel changed.

author: cdev
author_rank: Super Contributor
timestamp: January 24, 2016, 05:14:29 am
content: Quote from: coppice on January 23, 2016, 06:30:56 amA little tuning fork, kind of.
Moving RF wi-fi antenna jack/plug-in on other side of the PCB - Page 1
Forum section: electronics / rf-microwave

author: Vancata
author_rank: Contributor
timestamp: January 22, 2016, 09:44:50 pm
content: Hi Guys,Had some problems with my company laptop wifi integrated card, and seems something failed with the MB not with the card itself. Anyway since i'm the sys. admin in the company and I prefer to play instead getting new laptop or repairing this one with new motherboard (the book is out of warranty so I can do what i want with it). So I decided to integrate one USB wifi-card inside the nest of the CD-ROM, and place one HDD there too.So for this purpose I will directly solder the usb wi-fi card to one of the usb, and wont use it anymore. Was thinking to place some usb hub there too, but prefer to have the full band of this usb dedicated for the wi-fi card.I took the SATA/CD-rom converter from one caddy, placed the HDD then took apart the wi-fi card, placed it nice inside, but now the problem is I need to move that RF connector in the proper place, so i can place my antenna in the spot I want, and install some rails so the antenna can move in and out and look nice.In the attached picture, i need to move the antenna over the red dot I placed. I know RF lines are really sensitive for any change like lenght, resitance, close to each other and so one. Ground is fine, the whole PCB is layed out with one big ground plate on that side, but the signal lane im worried.I see one smd capacitor and right after it the signal line goes to the connector. I can soldier wire directly to the connector on the other side, clear some of the pcb and solder the ground but I think It would really make the antenna have worse parameters and loses since this tinny change of the signal line.Any ideas if this is really going to rune the performance of the module? It will be like no more then 1cm wire (10mm) from different material, lenght, resistance, in the "air" not around the grounded plates and so on.Thanks in advance guys

author: Ian.M
author_rank: Super Contributor
timestamp: January 22, 2016, 09:55:25 pm
content: At 2.4GHz a 1/4 wave is about 31mm long. More than 10% of that (i.e.3 mm) is likely to cause a significant change in performance.

author: Vancata
author_rank: Contributor
timestamp: January 23, 2016, 07:29:55 am
content: Thanks Ian!31.25mm for 2.4Ghz & 60mm for 5Ghz range, so 15mm for it, if i'm not mistaking the Lambda=v/fAnyway I did some ruffly measurements with some software tools under high load and found out the antenna boost only like 20% the signal (test was based on distance from the AP (access point). So anyway will go without the antenna.
What can be used instead of MRF559 transistor - Page 1
Forum section: electronics / rf-microwave

author: zeino
author_rank: Newbie
timestamp: January 12, 2016, 05:57:34 am
content: Does anyone have an idea what transistor can be used instead of MRF559 which is discontinued. Googled it and I found someone saying freescale produced itfor while but freescale is also bought and there is no more info regarding this piece.

author: TheSteve
author_rank: Unknown
timestamp: January 12, 2016, 07:13:38 am
content: Try rfparts.com - they appear to have them in stock.

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 12, 2016, 08:30:56 am
content: http://www.downeastmicrowave.com/product-p/mrf559.htmhttps://www.rfparts.com/rftransistors/transistor-mrfsrfm/rftransistors-mrf-500/mrf559-mot.html

author: wraper
author_rank: Unknown
timestamp: January 12, 2016, 10:04:45 am
content: You can get MRF559 on ebay. Though better to avoid Chinese sellers as counterfeits are possible.

author: zeino
author_rank: Newbie
timestamp: January 30, 2016, 07:21:14 am
content: Thanks for the replies, I bought them from RFparts. I hope they are real. I saw it on ebay. I wanted to avoid it totally and go for equivalent but I can not find any document that shows what has been produced instead. I know Freescale bough the Motorolla and himself got bought but I expected something on the net about the obsolete parts but it seems it is not so.
[Melbourne] QRP by the Bay gathering - Saturday February 6, 2016 - Page 1
Forum section: electronics / rf-microwave

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: January 21, 2016, 11:48:26 am
content: A twice-yearly social gathering for radio hams and other builders/tinkerers of radio/electronic gear. Everyone welcome - ham or not. It's a public area and no charges apply.It's 3 - 6pm on Saturday Feb 6. Often followed by a meal at a nearby restaurant. We usually get around 20 attending.Bring any projects, equipment, antenna or accessories. Gather in Victory Park, Camp Street, Chelsea, grassed area near the surf live saving club.Venue has good train, bus and car access and there are many facilities a short walk away.Here's a write-up on last November's.https://vk3hn.wordpress.com/2015/11/17/qrp-by-the-bay-saturday-14th-november-2015/Event info on Facebook at:https://www.facebook.com/events/1079084038781902/To recognise the venue, here's a video showing where we'll be.
Videos that explain the black art of RF design - Page 1
Forum section: electronics / rf-microwave

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: January 16, 2016, 07:04:05 pm
content: RF design has a reputation as a 'black art'. Circuits don't always behave as one would expect on the diagram. Amplifiers may oscillate. Oscillators may not start. And switches can act as low value capacitors that can wreck a circuit's operation.Mainly through describing shoddily constructed equipment a few of my videos discuss these subtleties of RF design. Most of them are part of description of a larger project or modifications so you may need to search for the discussion. Here's a couple of recent examples:1. This video, which only came out this morning, discusses the modification of a cheap Chinese transceiver kit to produce more frequencies by switching in a ceramic resonator variable crystal oscillator. You'd think it would just be a matter of inserting a switch, but not. Two switch configurations failed until I came with an arrangement (which shorted out the unused device) that worked properly.2. This video describes parasitic oscillations on a variable crystal oscillator (VXO). Arduino builders etc intend crystals to operate at their marked frequency only. Whereas RF people sometimes want to 'bend' its frequency a little so add series L and C. The more reactance you add the more shift you get. But only up to a limit when the thing breaks into drift and/or spurious oscillations as the coil and capacitor take over from the crystal as being the main frequency determining element.(Note that this video is No 2 of a 3 part series which discusses the development of a superhet transceiver for 7 MHz. Parts 1 & 3 are below:)3. Building very simple and terribly performing equipment and trying to improve it is a good way to learn. Here I discuss treatments to RF breakthrough in a (too?) simple receiver.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: January 16, 2016, 07:45:29 pm
content: Peter,Very clever way of shifting the frequency around in the pixie.Never have thought about doing it like that.Brilliant, thanks for posting these. I enjoy watching your videos.

author: miguelvp
author_rank: Super Contributor
timestamp: January 16, 2016, 09:20:55 pm
content: Brilliant, I have very little RF knowledge and it's scary that it all made sense.I might have to buy your book now, not for QRP application but to understand a bit better the RF world for other purposes than radio.

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: January 16, 2016, 10:49:39 pm
content: Thanks! The book isn't really technical - only has one schematic diagram in 200+ pages. Its more about antenna selection, equipment choice & operating. So probably not quite what you want.I suggest vk2tip's website. Also talking electronics. And get anything by drew diamond, Doug demaw, wes Hayward, pat hawker & rick Campbell. Experimental methods for rf design is the best current book. Also arrl & rsgb handbooks.
Auckland HAMs? - Page 1
Forum section: electronics / rf-microwave

author: apelly
author_rank: Unknown
timestamp: January 03, 2016, 06:49:35 am
content: One of Deathwish's recent threads inspired me to ask around a bit and do a bit more research about HAM radio. It turns out the amateur license exam over here isn't too onerous at all. That makes it almost a priority!Are there any Kiwis here involved in the scene?

author: Shock
author_rank: Super Contributor
timestamp: January 03, 2016, 12:07:10 pm
content: Most people get involved by just turning up to a club meeting, not been to one for years but it's normally a friendly atmosphere.http://radio1nz.com/about-amateur-radio/amateur-radio-clubs-in-auckland/

author: hendorog
author_rank: Super Contributor
timestamp: January 16, 2016, 08:13:19 am
content: North Shore ham hereI'm not active much, but know a couple of local guys who are.The amateur exam at the local branch is straight forward, run well, and takes one weekend. They walk you through the syllabus and all of the questions and answers. On the Sunday PM you sit the exam with a subset of the questions you have studied.The meetings are fairly unexciting affairs in general, primarily boring boilerplate club management stuff. There is some desire to improve that however.

author: apelly
author_rank: Unknown
timestamp: January 16, 2016, 08:59:07 am
content: Yes hendorog. I've communicated with Julian a couple of times. I'm booked in for the next exam weekend.Been slugging away with morse practice. If you can call it that. It feels more like typing randomly in a blind panic.
SoC or RF Receiver chip for at least 900-950mhz at least?  - Page 1
Forum section: electronics / rf-microwave

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: December 08, 2015, 11:15:22 pm
content: Im looking to make a cheap pc based receiver for an NTSC wireless camera. I would like to put this guy on my robot. I got the camera with no receiver modules. I cut the connector off connected to 12 volts and ran a scan with a dongle at 900-1000So it looks like I need to get a chip that can handle at a minimal of 15mhz, probably 20 to be safe. Is there an easy solution for this? I ran the data through TV Sharp and could not get any real picture due to the 3.2mhz bandwidth limit. But I also was getting something everything around the frequency was white noise static and then as soon as I hit 914mhz I started seeing some blackness with white rolling bars. You can also see in the picture the modulation changed a bit, this was due to me putting my hand over the sensor.I could even open it up and try to shift the broadcast frequency down... but I still need something cheap/homebrew with 15 mhz of bandwidth at the least.Why you ask?? Well camera was free and its color night vision I want to put it on my robot and pump the data through openCV. I dont really have money to go out and but a better solution, and even if I had one I would rather have my own reciver that works how I want it to, not the company.If anyone cares it is an ASTAK CM-918
Norma/ LEM/ Fluke 4000 Power analyzer pictures or manual - Page 1
Forum section: electronics / general

author: Amper
author_rank: Frequent Contributor
timestamp: February 02, 2022, 08:00:29 pm
content: Hi!I just scored another dumpster find that needs some fixing.The power analyzer is mostly complete but i suspect a crucial component is missing. On the main board there seems to be a connector for an additional daughter board, if im unlucky its the computation board but im not sure. The slot is roughly the same as a DDR3 slot so maybe its just memory?Is there anyone out there who can show me what the inside of a compete unit is supposed to look like?Does anyone have a service manual?The device shows a glowing but blank screen upon turning on.Hopefully there is a wy to save it

author: Amper
author_rank: Frequent Contributor
timestamp: February 02, 2022, 08:21:21 pm
content: nevermind...looks like the only broken hing was the display signal cable being unplugged. wtf?self test ok.Im still curious about documentation though!

author: Amper
author_rank: Frequent Contributor
timestamp: October 15, 2025, 07:30:11 pm
content: For a Request via PN here are some images of the instruments insides for the display Type and general overview:

author: miro123
author_rank: Frequent Contributor
timestamp: October 16, 2025, 06:35:45 pm
content: I dont know what I exactly see on picture.General remark - You most likely are missing the 4-th card. Most PS has four channel - Typical application is 3 Phase + 1DCAre the Voltage and current channels working? Do you have current sensors?
miniGPS Reference Clock (Bodnar) broken - Page 1
Forum section: electronics / general

author: perge
author_rank: Newbie
timestamp: October 14, 2025, 03:39:03 pm
content: Hi all,I have been using a lovely Leo Bodnar minGPS Reference Clock with an outside GPS antenna to provide reference for an HP8591E specan and an HP8647A generator. It had been running continuously 24/7 for years. Now, despite seeing plenty of satellites, it refuses to lock and there's no 10MHz output. Has anyone experienced this?

author: Jan Steinman
author_rank: Contributor
timestamp: October 15, 2025, 07:26:08 am
content: Leo Bodnar is pretty responsive. I got answers to questions within a day. You might want to ask them if they can fix it.

author: squadchannel
author_rank: Frequent Contributor
timestamp: October 15, 2025, 07:54:06 am
content: you should hide things like maps and coordinates.

author: Leo Bodnar
author_rank: Frequent Contributor
timestamp: October 15, 2025, 11:21:06 am
content: Hi,Send us an email with details tosupport@leobodnar.comand we will sort it out.CheersLeoQuote from: perge on October 14, 2025, 03:39:03 pm

author: perge
author_rank: Newbie
timestamp: October 15, 2025, 11:59:10 am
content: Thanks for the quick replies. I will contact suppport.
[Wanted] HP 85032A Cal.Kit Standard  Coefficients  - Page 1
Forum section: electronics / general

author: FPSychotic
author_rank: Regular Contributor
timestamp: July 31, 2025, 08:12:59 am
content: Hi, I got an HP 85032A calibration kit for a HP 8753B VNA but it has not such Kit in firmware.It is a old kit, it was used in HP 8410b and other VNA of that times.I'm used the 85032B coefficients as are the ones by default in my 8753B firmware, I thought maybe they just used the same parts. It looks worked very good, maybe I make other post with my findings.Asked Keysight and they say doesn't have records of it.

author: ElizatronicWarfare
author_rank: Contributor
timestamp: July 31, 2025, 10:51:50 pm
content: Is the kit's last calibration still valid? Cal factors will come from the last valid calibration.

author: FPSychotic
author_rank: Regular Contributor
timestamp: August 02, 2025, 11:34:01 pm
content: No,.I bought it second hand without any paper.I'm looking by generic coefficients as the ones came in the VNAs firmware. I know will be variation , but should be minimal and Im hobbyist

author: virtualparticles
author_rank: Regular Contributor
timestamp: October 13, 2025, 01:12:16 pm
content: Here you go:
Keithley 485 picoammeter IEEE interface card schematics - Page 1
Forum section: electronics / general

author: krasnopol
author_rank: Contributor
timestamp: October 08, 2025, 09:45:22 am
content: Hi everybody,I am searching the Keithley 485 picoammeter IEEE interface card schematics.The manual available on the web (model 4853 rev C, october 1987) includes the part list but unfortunately neither the schematics neither the component location drawing.Do you have a copy of these two pages ?A similar card is used in the 175 and 175A multimeters (model 1753 and 1753A) but the manuals on the web don't include these pages.Regards.Edmond

author: picburner
author_rank: Frequent Contributor
timestamp: October 09, 2025, 05:19:02 am
content: Here's thelinkto the manual with schematics.For the eprom, you can find the file 4853-800-A1 in internet. I think the revision (A1) should be the same as the instrument's main board.

author: krasnopol
author_rank: Contributor
timestamp: October 10, 2025, 05:52:09 am
content: Thank you very much for your help.According to the Eprom, my 485 revision is C1 and my 4853 works with it.Best regards.Edmond

author: picburner
author_rank: Frequent Contributor
timestamp: October 10, 2025, 09:02:45 am
content: You are welcome.If you have the 4853-800-C1 eprom revision, could you share the dump?Only revision A1 is available online.

author: krasnopol
author_rank: Contributor
timestamp: October 11, 2025, 05:29:51 am
content: Hi,The 485 self diagnostic program revision number is C1 and my 485 Eprom is labelled 485-800 C1.But the 4853 Eprom is labelled 4853-800 A1.Here is the 485-800 C1 hexintel file (U113.hex).U113.hex(19.28 kB - downloaded 12 times.)Best RegardsEdmond
At my limit with Raspberry pi 4B PPS NTP server? - Page 1
Forum section: electronics / general

author: MarginallyStable
author_rank: Regular Contributor
timestamp: September 28, 2025, 04:59:58 pm
content: So I have been working to see how stable I can get a raspberry pi ntp server with pps.I an using a custom buildroot distro, stock rpi 4b, and the ultimate gps hat. I have implemented many of the standard tricks found online:ntpheat to 65deg, enclosed the board in a plastic box, etc. I also went a bit further and isolate a cpu core as well as moving all interrupts other than the gpio interrupt from this core. I modified the gpio pps driver to implement gpio polling starting 1 ms before the expected pps to mitigate any interrupt latency. I'm pretty happy with the results and wanted to share. I do have one question, I have a syncserver S200 with OCXC sitting next to this setup and on the same network. I setup a noselect peer so I can get comparison stats. NTP show an average offset of -29.73us to this server. Is this a typical offset for two ntp servers in the same network with no hops or should I be able to expect better?

author: CalibrationGuy
author_rank: Unknown
timestamp: September 28, 2025, 05:31:25 pm
content: Maybe ask in the microcontroller forum?TomG.

author: MarginallyStable
author_rank: Regular Contributor
timestamp: September 28, 2025, 05:40:47 pm
content: My apologies if this is the wrong forum, seems there was a fair amount of discussion around syncservers here that this question would not be out of line.

author: CalibrationGuy
author_rank: Unknown
timestamp: September 28, 2025, 05:46:47 pm
content: No apologies necessary. Just trying to get you a quicker response. There are many very knowledgeable people on this forum.TomG.

author: ddrown
author_rank: Newbie
timestamp: September 28, 2025, 05:54:38 pm
content: With the pi 4, you're using kernel timestamps (which have interrupt latency&jitter) for the network traffic. You might want to try the pi 5, which has support for network card hardware timestamps. Switching to hardware timestamps requires some software configuration, and I can help with that if you'd like.The network path will include some amount of latency and jitter, especially if the syncserver is connected at 100M and the pi is 1G

author: hllns
author_rank: Newbie
timestamp: October 08, 2025, 10:01:52 am
content: I've read this guy's deep dive into PTP/NTP a while back and have been referring to a bit more recently as I'm looking to do try and evaluate some AV PTP setups using a PPS source and suitable Intel nic:https://scottstuff.net/posts/2025/06/10/timing-conclusions/He's done some work with Pi 5s, they're better but even there there are limits:https://scottstuff.net/posts/2025/05/27/cm5-pps-gpio-vs-nic/
"Precision Standard Time" model 1020 WWV/ WWVB Receiver - Page 1
Forum section: electronics / general

author: Stray Electron
author_rank: Super Contributor
timestamp: October 09, 2025, 09:58:25 pm
content: I cleaned out the storage shed of buddy of mine last week and this is one of the things that I picked up even though I wasn't sure what it was. But I got it out today and took a closer look and it's a WWV/ WWVB radio receiver from about 1987 that automatically receives, decodes and displays the time and date. With the advent of GPSDOs it's obsolete today but it's nice looking unit and this one looks like new and I'm debating whether it's worth keeping (along with a 1000 other projects!) Does anyone have any experience with these and if so what's your opinion?PRC68 has a a description of them and a very small picture. It's mentioned in other places on the net but I couldn't find a better picture.https://prc68.com/I/PST1020.shtmlFWIW I haven't tried to power it up yet. It runs off of 12VDC so I need to get out a PSU to try it and I also want to open it up and take a look inside before applying power. The weather, and the light, is crummy here today but I will try to get some pictures in the next couple of days.The Wikipedia article about WWV mentions the company and has a link to a 1988 patent that they held that was related to this model. It also appears that this might be the same or very similar WWV/ WWVB receiver that was sold by Heath/ Heathkit.

author: TimFox
author_rank: Super Contributor
timestamp: October 09, 2025, 10:05:54 pm
content: I noticed a bug claim in that review article about when the time display switches on Daylight Saving change days, switching on Colorado time (Mountain Time).My inexpensive LaCrosse “atomic clock” WWVB receiver/clock/thermometer is annoying (twice a year): instead of switching at 3 AM Central Time (Chicago time), it remains on the previous day’s time until midnight (9 hours late).

author: lugaw
author_rank: Regular Contributor
timestamp: October 10, 2025, 12:28:45 am
content: I think radio based time standard has the lowest accuracy in ms area. You can still search for old Seiko NTP time server that are module based that uses telephone, radio and GPS module and the radio is the lowest in the group. I got a Seiko TS-2550 with a radio module for cheap I was hoping to swap with a GPS module but couldn't find one. I also collected some radio based house clock and they are very slow in syncing just like the one mentioned in the article and sometimes they are off by a few seconds.

author: Stray Electron
author_rank: Super Contributor
timestamp: October 10, 2025, 01:13:38 am
content: I think that you're right about them having the lowest accuracy of any of the different systems other than just having a human listening to a radio and manually setting a clock. For one thing, I don't think that they have any way to deal with the varying atmospheric propagation delay.I notice that this one also has both an RS-232 port and an "Auxiliary Port". Does anyone know what's available on the auxiliary port?
4 mm ABS tube for low EMF contact Aliexpress - Page 1
Forum section: electronics / general

author: Overspeed
author_rank: Frequent Contributor
timestamp: September 26, 2025, 02:21:23 pm
content: HelloJust received 4 mm ABS tube lenght 250 mm , very cheap as 3.29 Euro x 10 pieces , these tube fit 4 mm banana socket easy and they are stiff .I link pictures of the Aliexpress page and the tube itself in the caliperRegardsOS

author: tszaboo
author_rank: Super Contributor
timestamp: September 26, 2025, 03:03:30 pm
content: OK.But why?

author: Overspeed
author_rank: Frequent Contributor
timestamp: September 26, 2025, 03:46:46 pm
content: HelloTo provide an alternative to cotton swabs as used by Marco Rep or Chinese stick or ....seehttps://www.eevblog.com/forum/metrology/chinese-metrology-accessories-list/50/post 53 ZlymexRegardsOS

author: mzzj
author_rank: Super Contributor
timestamp: October 02, 2025, 05:20:44 pm
content: I'd imagine plastic 4mm pneumatic line would also work for this. Nylon one is probably suitable stiffness and Polyurethane bit too flexy.

author: Overspeed
author_rank: Frequent Contributor
timestamp: October 04, 2025, 06:22:20 am
content: Quote from: mzzj on October 02, 2025, 05:20:44 pmHelloPerhaps but pneumatic line are delivred in spool and tube is not straight at all , there is perhaps a way to make them straight ?? , but as ready out of the parcel box these are staright and stiff enought .RegardsOS
Which oscilloscopes allow the best savings with codes / firmware updates ? - Page 1
Forum section: electronics / general

author: microvia
author_rank: Regular Contributor
timestamp: September 28, 2025, 05:17:36 pm
content: Hi,I have been working with a dual 100MHz Hameg (CRT display) and an "old" economic digital DSO-1102D (unlocked).I want to replace the DSO-1102D with a better model :- at least two 100MHz channels (4 would be better yet not required at the moment)- a larger HD screen, hopefully tactile (the DSO has a small 17cm one, and is not HD)- a better noise immunity- more importantly, a model fast enough to reduce the usual limitations seen on non-HD LCD displays, in order to look closer to a CRT model: less pixelisation effects, higher amount of samples per second (compared to my old DSO-1102D), and faster response.Although the question is broad, I wanted to know which models can save significant money by improving / enabling / adding functions after entering codes or using a different firmware. Thanks.
Fluke WW resistors - decode the markings - Page 1
Forum section: electronics / general

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: September 20, 2025, 08:35:14 pm
content: Hi group,I disassembled a Fluke 895A differential voltmeter to recover the precision resistors inside.The resistors are 0.01% WW. They were characterized by Fluke and collected into sets to build the Kelvin Varley divider.The first decade consists, 40kthis is built with two 19.999kand low-value WW trimmer in series. The resistors are in pairs. They are marked N.5 and P.5. I assume that this is the temperature coefficient code?The next decade is made from 8kresistors:It looks like these were also binned.How good are these resistors?Regards,Jay_Diddy_B

author: Vgkid
author_rank: Super Contributor
timestamp: September 20, 2025, 08:58:55 pm
content: You are correct. The n/p denotes tempco. The resistors should be rather stable.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: September 20, 2025, 08:59:09 pm
content: You did what !You’redismantling an 895A ! Sacrilege!! I really like my unit.I am shocked AND horrified.This is the kind of equipment I buy to refurbish and make videos about.But to answer your question the N is negative coefficient and P is positive coefficient.Or you could just leave the poor unit alone and buy some resistors.

author: trobbins
author_rank: Frequent Contributor
timestamp: September 20, 2025, 10:06:48 pm
content: https://www.eevblog.com/forum/metrology/fluke-895a-19-999k-precision-pairs/I managed to obtain a pair of those resistors. I fitted them into an enclosure with dual 4mm terminals per resistor terminal, and hard-wired them as a 1:1 divider - one arm needed 0.144R to balance the divider to better than 1ppm.

author: Hydron
author_rank: Super Contributor
timestamp: September 20, 2025, 10:42:41 pm
content: There is a 895A on ebay right now missing a cover if you want one to strip without guilt. If they were hermetic Rs then I would have already bought it, as I need some to build a reference resistor (I do have a bunch of hermetic ones on a Fluke 335D resistor string board, but kinda want to keep those as a usable unit).Does anyone know if any of these relatively cheap fluke differential voltmeters (inc. the 88x series) have hermetic Rs?Alternatively I might try and put some of the green guys in a re-purposed hermetic capacitor can - if anyone wants to sell me a pair/quad of tempco matched resistors that make a 10k-ish value from one of these then please let me know!
Keithley 4200 Parameter Analyzer - Page 1
Forum section: electronics / general

author: moosebiscuit
author_rank: Contributor
timestamp: September 15, 2025, 09:40:09 pm
content: Hello everyone.Just reaching out to see if anybody has any experience with these suckers. I want to bring these into our in-house lab if possible. It's just voltage source/meas & curr source/meas. I'm curious on whether Tektronix uses Clarius+ or KXCI commands for the calibration process. Are calibration adjustments proprietary? I can't seem to find anything in any of the associated manuals. Based on their calibraltion data, they do an incoming check, cal, and outgoing check. I wonder if this cal is just the ACAL. Any input would be very appreciated, thanks.

author: Brad O
author_rank: Regular Contributor
timestamp: September 16, 2025, 06:44:26 pm
content: I'm pretty sure calibration is done through an admin version of KCon. It's for sure not done through Clarius, but there might be a bit of KXCI automation. I think calibration is proprietary but it never hurts to ask. The factory calibration of the SMUs includes adjustment, not just the ACAL.

author: moosebiscuit
author_rank: Contributor
timestamp: September 17, 2025, 09:48:57 pm
content: Thank you for this info! Do you know how accessible the admin version of KCon is? Unfortunately I don't have one of the units on hand at the moment to play around with.
Keithley 610C Cable - Page 1
Forum section: electronics / general

author: CalibrationGuy
author_rank: Unknown
timestamp: September 18, 2025, 02:30:43 am
content: Just found a Keithley 610C without an input cable. Lots of contradictory information on modern replacement equivalents. Does anyone know where to get this cable, or how to replace it?TomG.

author: EC8010
author_rank: Frequent Contributor
timestamp: September 18, 2025, 08:34:29 am
content: The 610C is from before triax inputs, so replacement is easy. Any RF coaxial cable having a decent (no holes) braid screen will do. RG174 would be fine, but RG59 (75 ohm) or RG58 (50 ohm) are not so good because their braid has holes. I'd replace the input connector as well. Not because it was a poor original choice but because it has probably got dirty (leaky) over the decades. That's why electrometers should have protective caps over their input connectors (and also over their associated cables). Be aware that the longer the input cable, the higher the shunt capacitance and noise gain of the meter. Keep it short.All electrometers are horribly sensitive to capacitively coupled hum (hence that need for a good screen) and you should always have an oscilloscope on the pre-amp (chart recorder) output to check that you have minimised hum before believing any DC measurement. The best electrometer measurements are made inside earthed biscuit tins connected by ashortcable to the electrometer.

author: CalibrationGuy
author_rank: Unknown
timestamp: September 18, 2025, 02:29:10 pm
content: Thank you for your response. I bought it to check our fluke 720A divider. Nulling it with our 3458A was an exercise in frustration and futility.TomG.

author: CalibrationGuy
author_rank: Unknown
timestamp: September 18, 2025, 02:30:01 pm
content: And yes, I read their white paper on how to do it.TomG.

author: EC8010
author_rank: Frequent Contributor
timestamp: September 18, 2025, 03:00:21 pm
content: You've lost me. How would an electrometer allow you to check a Kelvin-Varley divider?

author: CalibrationGuy
author_rank: Unknown
timestamp: September 18, 2025, 03:23:54 pm
content: The 610C has a center zero setting with 1mV full scale range.TomG.

author: guenthert
author_rank: Frequent Contributor
timestamp: September 18, 2025, 03:37:35 pm
content: Quote from: CalibrationGuy on September 18, 2025, 03:23:54 pmThat might be so, but iirc the 720A wants a null to be less than 0.5µV to meet specifications. Fluke recommends (of course) their 845 Nullmeter, which has a minimum full scale range of 1µV.Don't know about the 610C, but the little more recent ("brown era") 617 has an output taken directly from the pre-amp. There a more sensitive instrument could be attached to. The combination is still noise limited though.

author: CalibrationGuy
author_rank: Unknown
timestamp: September 18, 2025, 05:00:42 pm
content: You are correct, this is not nearly sensitive enough.TomG.
Megger MS5000 power line sensors: how they measure line voltage? - Page 1
Forum section: electronics / general

author: hanakp
author_rank: Regular Contributor
timestamp: September 11, 2025, 10:21:26 pm
content: Megger makes really nifty wireless sensors for high-voltage power lines:https://www.megger.com/en/products/ms5000They derive power supply from current flowing through the line and have internal battery to keep them working during outages. Obviously they measure line current and also itsvoltage. But... how does it work, exactly? The sensors are just isolated "boxes hanging on wires", with no direct reference to earth or neighboring phases. In theMS5000 manual, they mention it's best to install the sensors at least 3 meters from poles:There is an advantage to locate the sensors 3m from the pole (rather than closer) because the electric field near the pole changes when it is raining or when there is a moisture on the pole. This is especially evident for concrete poles. In such cases of proximity to the pole will increase the fluctuation of the voltage measurements in raining times.And onanother pageof the manual, they mention an aluminum bracket that's needed to improve voltage measurements on insulated power lines:Bracket accessory made of Aluminum with hard anodize finish, which can be attached to the sensor for installation on insulated wires – used to improve the voltage measurement performance of MS5000.So they measure electric field intensity at the surface of the sensor casing or something? And how? They claim voltage measurement accuracy of 10%.

author: themadhippy
author_rank: Super Contributor
timestamp: September 11, 2025, 10:43:05 pm
content: at a guess same way all transformers work,the power line is the primary and theirs a coil in the sensor thats the secondry
Symmetricom Syncserver S300 CF images? - Page 1
Forum section: electronics / general

author: mattik
author_rank: Newbie
timestamp: August 13, 2022, 06:18:25 pm
content: Hi all,while trying to add root ssh access to my Syncserver S300 I probably messed up something and now the unit has stopped bootingBoot stops at the Loading OS screen, the hourglass stops turning after a while. I tried S250 and S350 images and got the device to boot but then either the display or the buttons are nonfunctional.Could someone please direct me to a (preferably already modified for root SSH access) CF image(s) for the S300?

author: usagi
author_rank: Frequent Contributor
timestamp: September 10, 2025, 02:43:46 am
content: did you ever figure this out? my S300 stopped booting also.
Inside a MAC(Miniature Atomic Clock) SA 54m - Page 1
Forum section: electronics / general

author: errolt
author_rank: Newbie
timestamp: September 09, 2025, 07:42:33 pm
content: Hi All,These photos aren't the best, but they are better than what I could find on the net( IE, none...).I had a MAC that wouldn't lock, unless I placed it upside-down? After fiddling with it a bit I replaced a FET, used as a heater, inside the silver box(Rb gas cell), now it seems to be happy again and locks within a few mins from startup.Now, does anyone have firmware for the Timeprovider 4100? I'm on 2.2.7, and 2.3 adds the ability to have time server and management on one port.... And Microchip is doing the HP/IBM thing: "The resource you are trying to access requires an Active Support Contract."
GW Instek GOM-802 milliohm meter calibration procedure - Page 1
Forum section: electronics / general

author: Machlee
author_rank: Contributor
timestamp: September 08, 2025, 02:46:59 am
content: Hi everyone!My GW Instek GOM 802 failed the test at the 30 mOhm limit.But I don't have a service manual. May be anyone has one. :'(
Fluke 5205A can be used as DC source? - Page 1
Forum section: electronics / general

author: smaultre
author_rank: Regular Contributor
timestamp: September 02, 2025, 04:26:45 am
content: Hello, just get one junky for free, and repaired it. Can i use it with DC calibrator? I need High Volt DC.

author: bdunham7
author_rank: Super Contributor
timestamp: September 03, 2025, 04:56:01 am
content: Yes, you certainly can. Be careful, it will do over 1.5kVDC @ >0.1A.

author: smaultre
author_rank: Regular Contributor
timestamp: September 03, 2025, 08:05:20 pm
content: Its a good news! Yes i understand that its dangerous!Another one quest it have proprietary high-volt connector on its cable end.Is there any compatible "female" connector ?

author: bdunham7
author_rank: Super Contributor
timestamp: September 03, 2025, 08:46:02 pm
content: Those are just standard bananas with a standard 3/4" spacing. For older meters with protruding binding post terminals, it will slip right on. For newer meters you need some simple banana adapters (extensions).
Krohn Hite DC Source - Page 1
Forum section: electronics / general

author: laida232004
author_rank: Newbie
timestamp: September 03, 2025, 03:37:16 pm
content: Hello everyone. Newbie here and have a couple of questions about using 523 as voltage source for calibration of Validators. Hoping I could get some insights from the community. We've just acquired the new DC source to replace our old model- 511. During our recent calibrations of validators using the new model 523, we noticed that we had a lot of failed results (every single one). Readings are very inconsistent, readings fail, gets adjusted, but then drift or fail again shortly afterward. This has raised concerns about the reliability of the new DC source. Here are some things that we tried that seem to help but not completely solved the issues:* Increased the warm-up time to at least 4 hrs= seem to help since most of our readings passed but we are still getting some failed setpoints.*Connection set-up= we used the same leads from the old model (511), should we use the leads recommended by the manufacturer? Will that make a lot of difference?*Should we perform a output voltage check?*Read about the Auto Zero Offset Calibration, is this something we can do? Does this need to be done every time we use the equipment?We'd really appreciate any guidance, similar experiences or troubleshooting steps others have used when dealing with DC Source drift or inconsistent readings.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 03, 2025, 03:42:18 pm
content: may be of some helphttps://www.eevblog.com/forum/repair/krohn-hite-523-calibrator-alignment-adjustment-procedure/user manual attachedREAD LINE 3 apparently you may or will need to purchase the software
Need help with a Ballantine 1600A - Page 1
Forum section: electronics / general

author: Zenwizard
author_rank: Regular Contributor
timestamp: April 11, 2025, 01:48:08 am
content: As the title states I have a sick one of these one the bench in for repair. After spending a few day scraping the web I have not been able to locate a service manual for the 1600A it is an AC thermal transfer standard. In my unit the Null meter works as well as the auto Null function however it will not switch to DC mode setting the unit to manual allows DC to output however it is about a volt low. Testing with a 5 Volt source. The weird part is in manual mode the unit works. supply can be nulled out and it is highly accurate at least at first glance.Seeing if anyone has any ideas on what might be wrong as well as a possible service manual for this unit. After repair I would like to touch up the calibration as i should really check the 5200A that I have here in the lab.Zen

author: doktor pyta
author_rank: Frequent Contributor
timestamp: April 12, 2025, 05:02:07 pm
content: I own 1600A and have a paper manual for it.This month i'm not able to scan the whole manual, but if You need page or two i can place a photo.The 1600A uses nanovoltmeter built with a mechanical chopper and a transformer.The chopper is the weak point, but You are lucky one if Yours works OK.

author: _Wim_
author_rank: Super Contributor
timestamp: April 19, 2025, 06:38:53 pm
content: It is not the full service manual, but still quite useful...They still sell a full service manual (at least when I asked many years ago, but was quite expense > 100$ for a digital version)

author: _Wim_
author_rank: Super Contributor
timestamp: April 19, 2025, 06:39:25 pm
content: The second part...

author: _Wim_
author_rank: Super Contributor
timestamp: April 19, 2025, 06:40:44 pm
content: Looking forward for the youtube video on the 1600A

author: _Wim_
author_rank: Super Contributor
timestamp: August 27, 2025, 08:23:55 pm
content: Nice video!
Metrology Society of Australasia Conference, Sydney, 25th - 28th August  - Page 1
Forum section: electronics / general

author: BarrowBoy
author_rank: Contributor
timestamp: August 21, 2025, 06:19:11 pm
content: Hi Folks,The Metrology Society of Australasia Conference takes place next week in Sydney. As a sponsor & MSA Member I've got a spare day pass to attend in person. Normally $450.I'm looking for a Voltnut (preferably in the industry) based in Sydney, or willing to travel. Depending upon your discipline you would choose the relevant day. One catch I will need to process this ticket within 10 hours from now...sorry for the short notice.https://metrology.asn.au/events/msa-conference-sydney-aus-25-28-august-2025/For Interstate and Overseas Voltnuts, a couple of the sessions will be livestreamed ( known as Metrology 101), and there are still a few tickets to attend in person. These 2 "Metrology 101" sessions are free. But my offer is a day pass which allows access to the deeper dive stuff.https://metrology.asn.au/events/metrology-101-free-session/I did discuss this conference with Dave, and I do believe he intended to come along in person, but his back injury does not allow that.I'll check my DM throughout the day, to check on level of interest, because as mentioned I need this done by 2pm Sydney time today.

author: BarrowBoy
author_rank: Contributor
timestamp: August 22, 2025, 04:14:59 am
content: DAY PASS OFFER CLOSED, not a single enquiry. I'm surprised. The free 101 sessions remain open for a bit longer. Have a great weekend. If your in Sydney, take a Umbrella..lol. Can't believe the rain we have had this month.
...LT1019: Any long term stability data available ??? - Page 1
Forum section: electronics / general

author: VE2UM
author_rank: Contributor
timestamp: August 18, 2025, 06:56:55 pm
content: Hi...I use many Buried Zener voltage references ( REF102C, MAX5350, LM199 and soon a ADR1001 )... Also a Fluke 8800 using an SZA263 Refamp......But would like to jump the fence to add a Bandgap reference. The unit i was looking is an LT1019-10...Unfortunately, i didn't fid any data on long term stability for the 1019 in their PDF...Does anyon ever experienced with the LT1019 and got any data on its long term stabilityOr, do you have another BG reference to suggest me ?Thank you...

author: zlymex
author_rank: Frequent Contributor
timestamp: August 19, 2025, 01:41:02 am
content: LT1019-10, bandgap, LF noise 2.5ppm (p-p)AD584(10V), bandgap, LF noise 5.0ppm (p-p), 25ppm/1000 hrsREF5010(10V), bandgap, LF noise 3.0ppm (p-p), 50ppm/1000 hrs(SOIC, after 1khrs)LT1021-10, buried zener, LF noise 0.6ppm (p-p), 15ppm/1000 hrsLM369(10V), buried zener, LF noise 0.4ppm (p-p), 6ppm/1000 hrsREF102(10V), buried zener?, LF noise 0.5ppm (p-p), 5ppm/1000 hrs(M package)LTZ1000(7V), buried zener, LF noise 0.17ppm (p-p), 0.3ppm/1000 hrs

author: Andreas
author_rank: Super Contributor
timestamp: August 19, 2025, 06:04:13 am
content: Hello,what I would expect:~100 ppm initial driftafter that seasonal changes dependant on humidity and package.I have one LT1019CCN8-5 (5V Version in DIP8) in my ageing box.Initial drift was ~120 ppm then ~20 ppm seasonal changes. (green line on right y-axis in ppm. X-axis is in days)Note that I heat my ageing box to 50.0 deg C every day for ~2 hours during measurement.So humidity changes may be more for room temperature and usually also more for SO-8 package.with best regardsAndreas