Re: [qrptech] FYI Cheap ($2!) vernier dials from Aliexpress
Send me the Link and I make you a screenshot. On January 4, 2024 6:51:58 PM GMT+01:00, "Michael A. Terrell" <terrell.michael.a@...> wrote:
You can search TEMU and other sites with Google. Describe the item, theen? add the company's name after a space. I see a 10 or 20 turn pot and dial for under $4 on Temu, but my satellite internet is horrible, so I can't view te page. The severe latency causes many websites tio time out on me. It is a high orbit 55 GHz link.
With best regards Tam HANNA -- Enjoy electronics, 3D printing and cigars? Join more than 21000 followers on my Instagram at
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Re: [qrptech] FYI Cheap ($2!) vernier dials from Aliexpress
You can search TEMU and other sites with Google. Describe the item, theen? add the company's name after a space. I see a 10 or 20 turn pot and dial for under $4 on Temu, but my satellite internet is horrible, so I can't view te page. The severe latency causes many websites tio time out on me. It is a high orbit 55 GHz link.
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Re: [qrptech] FYI Cheap ($2!) vernier dials from Aliexpress
Well, sorry about the inaccurate price. I got 10x for $38.65. It was a portion of a larger order. Sometimes I order 10x and get shipping charged for one. In this case I obviously did not care. It was still a fraction of the lowest price I'd ever seen. Obviously you're not interested in small vernier dials.
I've gotten multiple refunds from Aliexpress. I've been pleasantly surprised. As easy as ebay. So now I search ebay, Amazon, Temu and Aliexpress. Anyone of them may have the best price at any time.
I posted about these because both Temu and Aliexpress search is quite flaky. Because of history, these were thrown up in a page of random stuff. presented to me. I thought they would be of interest to others in these 3 lists so I posted a link. I only discovered Temu because of a post to qrptech.
Have Fun!
Reg
On Wednesday, January 3, 2024 at 11:58:18 PM CST, Roy Thistle <roy.thistle@...> wrote:
On Tue, Jan 2, 2024 at 05:14 PM, Reginald Beardsley wrote: forgot to mention that if you pay 2USD for one, you pay about 2USD for shipping too... unless... and maybe you can find...as you search through Ali, one for 2USD... with free shipping. IMO, that won't happen. And as soon as you order two, the shipping jumps up to about double... unless there are small parts, under a certain weight. IMO... and I do get stuff from Ali... unless you like spending hours looking for bargains... are prepared for perhaps for substandard stuff (relative to expectation)... and are are prepared lose your money... and are prepared to spend even more time messaging sellers... and trying to track shipments too...? Then, IMO... Ali is only sometimes a bargain. If I had the money I think some other people have... to spend on this stuff... I wouldn't be doing it. Temu is something else. Maybe Reg can find bargains on that?... I can't.? I believe its the USPS shipping costs that kill it.
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Re: [qrptech] FYI Cheap ($2!) vernier dials from Aliexpress
On Tue, Jan 2, 2024 at 05:14 PM, Reginald Beardsley wrote:
forgot to mention
that if you pay 2USD for one, you pay about 2USD for shipping too... unless... and maybe you can find...as you search through Ali, one for 2USD... with free shipping. IMO, that won't happen. And as soon as you order two, the shipping jumps up to about double... unless there are small parts, under a certain weight. IMO... and I do get stuff from Ali... unless you like spending hours looking for bargains... are prepared for perhaps for substandard stuff (relative to expectation)... and are are prepared lose your money... and are prepared to spend even more time messaging sellers... and trying to track shipments too...? Then, IMO... Ali is only sometimes a bargain. If I had the money I think some other people have... to spend on this stuff... I wouldn't be doing it. Temu is something else. Maybe Reg can find bargains on that?... I can't.? I believe its the USPS shipping costs that kill it.
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That is truly a work of art. I was just eyeballing mine together while they finished running LED lamps and wire in my shop today. I still need to build the EMI filters and power them, but I've got 2 rows down the center running on extension cords to give light to work.
I have a complete machine and metal fab shop because of the work that packaging takes. I've spent $10 and 4 hours putting $1 and 20 minutes of electronics in a box more times than I can count. I've become a big fan of 28 gauge galvanized steel HVAC scrap for cheap simple box making. With soldered copper foil tape seals for RF.
I've been testing the verniers and I can set to 3 digits quickly and 4 with some fiddle using the 1 M pot and a 34401A in 4.5 digit 2 wire mode. I've replaced the OEM shaft screws with hex socket set screws which are much more convenient.
The 8:1 reduction is really sweet. I plan to buy a bunch more. I've got a bunch of large NOS National Velvets, but they are a bit big for most of my projects.
The photos show the vernier with the plastic removed. Considerably more elegant on a nice box.
Have Fun!
Reg
On Wednesday, January 3, 2024 at 07:20:28 PM CST, Paul Amaranth <paul@...> wrote:
On Thu, Jan 04, 2024 at 12:59:10AM +0000, Reginald Beardsley via groups.io wrote: > All those verniers cried for something to do, so I built a box with banana jacks and 100k and 1M linear pots.? Not sure I'll ever use it, but I had all the stuff on hand. Took a *lot* more time than I expected. > > Have Fun! > Reg When building a complete instrument it usually takes me 2-3 times as long to package it as it does to design/build the electronics and software.? Case fabrication, layout, labeling/painting, assembly, finding all the bits, it all takes time. A while ago I picked up an Acme PS2L-1000 kilowatt electronic load.? You can sometimes find them fairly cheap.? They're electrically programmable, but don't have any fancy controllers in the instrument (hence why they're cheap).? I built this unit to interface the load with a PC for logging and programmatic control.? Communication is over a USB or rs232 serial link with a simple protocol. BTW, if anyone has one of these loads and wants my design, just ask.? I'd be happy to share. ? Paul -- Paul Amaranth, GCIH? ? ? ? ? ? | Manchester MI, USA? ? ? ? ? ? ? Aurora Group of Michigan, LLC? |? Security, Systems & Software paul@...? ? ? ? ? ? ? |? Unix/Linux - We don't do windows
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On Thu, Jan 04, 2024 at 12:59:10AM +0000, Reginald Beardsley via groups.io wrote: All those verniers cried for something to do, so I built a box with banana jacks and 100k and 1M linear pots.? Not sure I'll ever use it, but I had all the stuff on hand. Took a *lot* more time than I expected.
Have Fun!
Reg When building a complete instrument it usually takes me 2-3 times as long to package it as it does to design/build the electronics and software. Case fabrication, layout, labeling/painting, assembly, finding all the bits, it all takes time. A while ago I picked up an Acme PS2L-1000 kilowatt electronic load. You can sometimes find them fairly cheap. They're electrically programmable, but don't have any fancy controllers in the instrument (hence why they're cheap). I built this unit to interface the load with a PC for logging and programmatic control. Communication is over a USB or rs232 serial link with a simple protocol. BTW, if anyone has one of these loads and wants my design, just ask. I'd be happy to share. Paul -- Paul Amaranth, GCIH | Manchester MI, USA Aurora Group of Michigan, LLC | Security, Systems & Software paul@... | Unix/Linux - We don't do windows
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All those verniers cried for something to do, so I built a box with banana jacks and 100k and 1M linear pots.? Not sure I'll ever use it, but I had all the stuff on hand. Took a *lot* more time than I expected.
Have Fun!
Reg
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Re: [qrptech] FYI Cheap ($2!) vernier dials from Aliexpress
Sorry. forgot to mention they are 8:1 ratio.
On Tuesday, January 2, 2024 at 05:48:56 PM CST, Reginald Beardsley <pulaskite@...> wrote:
An update on these: The range of rotation is ~300 degrees with clutched stops at the ends. They take a 6 mm shaft, so drilling out is needed to accommodate 1/4" shafts.? They are intended for single turn pots.? So you only get 0-60 in 180 degrees. However, with laser engravers common, a custom dial shouldn't be a problem.? So for anyone who is fond of pure analog radios they are a steal. I've attached one to an existing? breadboard variable and also showed the bracket which is included with an air trimmer in position, but not attached.? The air trimmer shaft just isn't long enough. There are a slew of other sellers, possibly at better prices. It changes constantly. This is all I have to say on this thread unless someone has a question.? I thought I should give people a heads up that these were available at such reasonable prices.
Have Fun!
Reg
NB link repeated because I forgot to copy the test list.
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Re: [qrptech] FYI Cheap ($2!) vernier dials from Aliexpress
An update on these:
The range of rotation is ~300 degrees with clutched stops at the ends. They take a 6 mm shaft, so drilling out is needed to accommodate 1/4" shafts. They are intended for single turn pots. So you only get 0-60 in 180 degrees. However, with laser engravers common, a custom dial shouldn't be a problem. So for anyone who is fond of pure analog radios they are a steal.
I've attached one to an existing breadboard variable and also showed the bracket which is included with an air trimmer in position, but not attached. The air trimmer shaft just isn't long enough.
There are a slew of other sellers, possibly at better prices. It changes constantly.
This is all I have to say on this thread unless someone has a question. I thought I should give people a heads up that these were available at such reasonable prices.
Have Fun!
Reg
NB link repeated because I forgot to copy the test list.
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Re: Open-hardware power rail oscilloscope probe
That's great advice. I tried something like that for a switch panel in my van, with an aluminium core PCB, but the finish wasn't great - I foolishly specified no silkscreen, hoping for a matte finish, and that was a mistake. I'll try again at some point, because it's a cheap front panel and you can reverse mount SMD LED indicators as Harvey suggested.
For this project, I wanted to test out an aluminium sheet metal manufacturer someone recommended () - the panels machined and anodised to spec came in at $3 each, which was ridiculous (about ?7 each once shipping is included for 2*10 panels). They took a while, and I'd recommend asking for sandblasting to reduce the risk of scratches on the finish, but otherwise great.
The PCBs were another experiment with a new supplier (). They were absolutely fantastic - quite expensive in small quantities, but a big step above the likes of JLCPCB. The test report received with the finished boards ran to 11 pages, and you get a big choice of prepreg, arbitrary stackups, and exotic core materials if required. Their volume pricing wasn't wild, either.
-Patrick
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Re: Open-hardware power rail oscilloscope probe
As another thought, you can drill holes and reverse mount surface mount LEDS (gull wing ones?) on the back of the board.? Put a sheet of transparent plastic over the PC board to protect it and the LEDs.? Will also work well with non touchscreen LCD displays. Any wiring needed for the front? panel controls can be on the back side.
Harvey
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Show quoted text
On 12/31/2023 2:18 PM, Sam Reaves wrote: You can save a lot of money on panels by designing the panels as double sided PCB's solid copper on both sides. The corner mounting holes as through holes with the OD of the throughole being close
to the diameter of the screw head. The just specify black soldermask with white ink. and label as needed. Works like a champ. I would recommend? backing off the copper from the board edge someting like
25 mils or so.
As an edge finish you either can use a matte black paint pen or stack up a bunch of them held together with painters tape and masked accordingly and then paint the edges with Krylon flat black spray paint. As long as they are tightly together and you just dust the edges with enough paint to cover (light coats) no paint will get between them.
Alternately you can try a black Sharpie and see how that works but one of my friends says that fades over time.
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Re: Open-hardware power rail oscilloscope probe
Excellent writeup and project! Would buy one immed but had some significant family medical costs in november. Tucked the info away for hopefully the near future. Thank you again, this will be very useful!
J
Patrick Coleman wrote:
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To revive an old thread, I wanted to give an update on the power rail probe project - I built out the prototype in October and spent the last few months characterising it. It works pretty well!
The frequency response (attached) is flat to 500MHz, as hoped, aside from a -3.7dB dip @ ~1.2MHz. That had me stumped for a long time, but after messing around in TI (TINA?) SPICE I believe it to be poor compensation in the inverting opamp U2 (see GitHub below for schematics).
I have some ideas for improvements, but the probe works really well for day-to-day use, and the frequency response is now well characterised should you wish to take more accurate measurements. I've attached a chart of 20mV p-p noise on a 20V rail from my bench PSU, taken with my cheap 10MHz Picoscope thanks to a 20V offset applied by the power rail probe.
My plan is to release the 8 boards I have here as v1.0 (with fancy machined front and rear panels, no less), and continue iterating on the design as time allows.
There's a detailed writeup on GitHub: (there's also a link there to purchase an assembled unit, or a blank PCB, both shipping from London, UK)
...and some more colour in this thread on Mastadon:
I really appreciate the detailed advice and feedback from the group back in August - it influenced and improved the design. If you get in touch directly, I can add a discount to your order (anyone on the group is welcome).
Finally - I'd really like to verify the noise measurements I've taken, because I'm not sure I entirely trust my setup(/methodology) here. If you happen to have access to a good spectrum analyser and well-characterised noise source, with the ability & patience to measure noise down to say -100dBm, and would be willing to measure the noise power across a bunch of frequency bands, I'd love to get in touch. I can pay you ... in power rail probes :^)
Cheers
Patrick
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Re: Open-hardware power rail oscilloscope probe
You can save a lot of money on panels by designing the panels as double sided PCB's solid copper on both sides. The corner mounting holes as through holes with the OD of the throughole being close
to the diameter of the screw head. The just specify black soldermask with white ink. and label as needed. Works like a champ. I would recommend? backing off the copper from the board edge someting like
25 mils or so.
As an edge finish you either can use a matte black paint pen or stack up a bunch of them held together with painters tape and masked accordingly and then paint the edges with Krylon flat black spray paint. As long as they are tightly together and you just dust the edges with enough paint to cover (light coats) no paint will get between them.
Alternately you can try a black Sharpie and see how that works but one of my friends says that fades over time.?
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Re: Open-hardware power rail oscilloscope probe
To revive an old thread, I wanted to give an update on the power rail probe project - I built out the prototype in October and spent the last few months characterising it. It works pretty well!
The frequency response (attached) is flat to 500MHz, as hoped, aside from a -3.7dB dip @ ~1.2MHz. That had me stumped for a long time, but after messing around in TI (TINA?) SPICE I believe it to be poor compensation in the inverting opamp U2 (see GitHub below for schematics).?
I have some ideas for improvements, but the probe works really well for day-to-day use, and the frequency response is now well characterised should you wish to take more accurate measurements. I've attached a chart of 20mV p-p noise on a 20V rail from my bench PSU, taken with my cheap 10MHz Picoscope thanks to a 20V offset applied by the power rail probe.
My plan is to release the 8 boards I have here as v1.0 (with fancy machined front and rear panels, no less), and continue iterating on the design as time allows.
There's a detailed writeup on GitHub:??(there's also a link there to purchase an assembled unit, or a blank PCB, both shipping from London, UK)
...and some more colour in this thread on Mastadon:?
I really appreciate the detailed advice and feedback from the group back in August - it influenced and improved the design. If you get in touch directly, I can add a discount to your order (anyone on the group is welcome).
Finally - I'd really like to verify the noise measurements I've taken, because I'm not sure I entirely trust my setup(/methodology) here. If you happen to have access to a good spectrum analyser and well-characterised noise source, with the ability & patience to measure noise down to say -100dBm, and would be willing to measure the noise power across a bunch of frequency bands, I'd love to get in touch. I can pay you ... in power rail probes :^)
Cheers
Patrick
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Re: Budget RF lab equipment list
On Tue, Dec 26, 2023 at 08:31 AM, Dr. David Kirkby, Kirkby Microwave Ltd wrote:
Tenure will be based on publications -
Unless you're applying to Harvard it seems :-) Morris (who was non-tenured)
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Re: Budget RF lab equipment list
Tenure can also be based on the factor of having enough money
that one can perform an universal gesture of love and kindness to
the university. Especially effective when the finger is erected
while seated in an exotic car or a first class seat.
Can be done. Has been done before.
/me did it. It felt great.
With best regards
Tam HANNA
--
Enjoy electronics, 3D printing and cigars? Join more than 21000 followers on my Instagram at
On 2023. 12. 26. 17:30, Dr. David
Kirkby, Kirkby Microwave Ltd wrote:
toggle quoted message
Show quoted text
On Tue, 26 Dec 2023 at 15:36, Reginald Beardsley
via
<pulaskite= [email protected]>
wrote:
When I referenced Youtube I was thinking of people
like Hunter Adams of Cornell who is looking for a tenure
track job. Lots of incentive to put his lectures on
Youtube.
Tenure will be based on publications -
not on YouTube videos.
Dave
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Re: Budget RF lab equipment list
On Tue, 26 Dec 2023 at 15:36, Reginald Beardsley via <pulaskite= [email protected]> wrote: When I referenced Youtube I was thinking of people like Hunter Adams of Cornell who is looking for a tenure track job. Lots of incentive to put his lectures on Youtube.
Tenure will be based on publications - not on YouTube videos.
Dave
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Re: Budget RF lab equipment list
When I referenced Youtube I was thinking of people like Hunter Adams of Cornell who is looking for a tenure track job. Lots of incentive to put his lectures on Youtube. Hunter is so good I watched about half the semester on the RP2040 just for fun. I learned embedded systems concepts years ago. But his enthusiasm is marvelous and his choice of projects fascinating.
On reflection I don't think I ever "learned" anything from Youtube. Videos have just called my attention to interesting topics or provided demonstrations. Mostly the latter.
I watch very few videos, even by people who are acknowledged masters of their field because I prefer books. My standard is 3 books on any unfamiliar topic I'm trying to learn.
I have periodically estimated the cost of a minimal RF bench for many years and this is the first time it dropped below $1000 for an extremely full featured lab. once the screen room is finished and my lab gear set up I'm going to do some projects with a budget setup and then go verify against my HP and Tek hit.
I bought a Toolium 135A MMA welder from Amazon for $68 and am about to go play with it and see if a 900,000 lumen spotlight will let me see where I'm trying to weld and not just the arc (macular degeneration). It weighs less than 10 lbs with the entire setup in an old CPAP bag. It won't go above 1/4", but that's typical repair work and it runs on 110 V if needed, though at reduced output. Watching a video won't teach you welding. Doing it will. Being able to assemble the kit to teach yourself welding for under $100 is a huge enabler. And then there are discarded bed frames ;-)
Have Fun!
Reg
On Tuesday, December 26, 2023 at 08:24:21 AM CST, Steven Greenfield AE7HD via groups.io <alienrelics@...> wrote:
On Fri, Dec 22, 2023 at 09:28 AM, Roy Thistle wrote: Can't say where other's went to EE school; but..
IMO... and in my university... it might have been different.
I'd say that tech talk on YouTube is mostly edutainment (nothing wrong with that for entertainment)
And pop-engineering books (even with a bit of math) are not very good... whilst... textbooks have gotten bad as well too. It is hard to replace a good instructor. However, it can be tough to figure out which schools have those good instructors. Most of my electronics knowledge is a result of the public library system.? Discipline in learning can be difficult. I have the fortune to be very single-minded when i want to know something. After high school, a lot of people assumed I was in college because I had a backpack that always had a textbook, grid paper, and a scientific calculator in it that would come out at every break and at lunch. At home, I did a lot of experiments in RF and other circuits. I experimented on myself to see what was the level of current was at the threshold of perception in my hands and arms (in case of accidental contact while working) and incidentally measured the approximate impedance of flesh (past the skin) at 50 to 200 ohms. Except for a 'scope (bought used) and a VOM (built from a Radio Shack kit), I designed and built most of my own test equipment. If a book didn't give me an "aha!" moment, I'd find more books on the same subject, make a lot of drawings, do some lab experiments, and think a lot about it. ? -- Steve Greenfield AE7HD WRWU703 CN87oa?? http://www.ae7hd.com
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Re: Budget RF lab equipment list
On Fri, Dec 22, 2023 at 09:28 AM, Roy Thistle wrote:
Can't say where other's went to EE school; but..
IMO... and in my university... it might have been different.
I'd say that tech talk on YouTube is mostly edutainment (nothing wrong with that for entertainment)
And pop-engineering books (even with a bit of math) are not very good... whilst... textbooks have gotten bad as well too.
It is hard to replace a good instructor. However, it can be tough to figure out which schools have those good instructors. Most of my electronics knowledge is a result of the public library system.? Discipline in learning can be difficult. I have the fortune to be very single-minded when i want to know something. After high school, a lot of people assumed I was in college because I had a backpack that always had a textbook, grid paper, and a scientific calculator in it that would come out at every break and at lunch. At home, I did a lot of experiments in RF and other circuits. I experimented on myself to see what was the level of current was at the threshold of perception in my hands and arms (in case of accidental contact while working) and incidentally measured the approximate impedance of flesh (past the skin) at 50 to 200 ohms. Except for a 'scope (bought used) and a VOM (built from a Radio Shack kit), I designed and built most of my own test equipment. If a book didn't give me an "aha!" moment, I'd find more books on the same subject, make a lot of drawings, do some lab experiments, and think a lot about it. ? --
Steve Greenfield AE7HD WRWU703 CN87oa??
http://www.ae7hd.com
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Re: Budget RF lab equipment list
I very much agree with the comments on the SN ratio of YouTube but there are, thankfully, exceptions - IMO one of the best is Alan (W2AEW).? To me he seems to consistently provide good information in a accessible format without a lot of filler.
Hal
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Michael A. Terrell
Sam Reaves
Dr. David Kirkby, Kirkby Microwave Ltd
Harold Foster