Nostr notes by Søren Kjærsgaard

Using my aging #buspirate 3.6 to read out a 24C02 in a defunct ...

2026-04-19T09:23:57Z

Using my aging #buspirate 3.6 to read out a 24C02 in a defunct kitchen scale.
It turns out it was surprisingly full of data 😳 Most of it likely calibration, but maybe also some intermediate stuffs since the chips write protection was permanently disabled.
Anyway, I just ordered a version 5 buspirate, seems like a decent upgrade 🤓 #EE #hardwarehacking #electronicsengineering

I bought a microscope with a HD camera 😄Any recommendations ...

2026-04-16T17:02:43Z

I bought a microscope with a HD camera 😄Any recommendations for camera SW that runs on a Mac? Need to be able to adjust gain, contrast, illumination(sensitivity), all that. Maybe do a bit of processing as well, but most importantly, it has to be simple. Total microscopy beginner here 🤷🏼‍♂️😂

I was told that it was new in the sense that ‘the N-Conn had ...

2026-04-15T15:23:24Z

In reply to nevent1q…kd6k
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I was told that it was new in the sense that ‘the N-Conn had never been used before’… I trust this, the person had no reason so say otherwise 🙂

One of those “it’s you or the dumpster” moments… How ...

2026-04-14T20:19:29Z

One of those “it’s you or the dumpster” moments… How could I possibly reject that? 🤷🏼‍♂️🤭

#rfengineering #rfengineer #hamradio

Wasn’t my radio, so I don’t know the history behind it, but ...

2026-04-14T18:57:51Z

In reply to nevent1q…7cpk
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Wasn’t my radio, so I don’t know the history behind it, but generally I use connector savers on my most precious gear ☺️

not my radio but yes, that was my first reaction as well (PL ...

2026-04-14T18:24:45Z

In reply to nevent1q…a6nm
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not my radio but yes, that was my first reaction as well (PL insertion). I have N ‘connector savers’ on some of my radios and more precious instruments. Just in case ☺️

Actual reason is unknown, it didn’t come out of my radio, but ...

2026-04-14T18:22:34Z

In reply to nevent1q…sngt
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Actual reason is unknown, it didn’t come out of my radio, but yes, that was my first reaction as well 🙂

Well that’s not supposed to happen 🤷🏼‍♂️😂 Came ...

2026-04-14T17:59:05Z

Well that’s not supposed to happen 🤷🏼‍♂️😂

Came from a brand new radio - I guess their quality control failed, - or caused it 🙂

#hamradio #tfengineer #rfengineering

God I love logperiodics 🥰 Such a fascinating structure - I ...

2026-04-10T21:08:22Z

In reply to nevent1q…x992
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God I love logperiodics 🥰 Such a fascinating structure - I have an alternate mail address: logperiodic@xxx.yyy 😂 I have several of them, some even calibrated (gain and AF)

the D3000 certainly wasn’t cheap, but I’m glad I got it. Plan ...

2026-04-10T20:53:35Z

In reply to nevent1q…x992
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the D3000 certainly wasn’t cheap, but I’m glad I got it. Plan to use it with my R-8600 and a Fobos SDR 🙂

exactly 😎

2026-04-10T20:25:36Z

In reply to nevent1q…7p9m
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exactly 😎

I recently got a R-8600, so I figured I could justify this and ...

2026-04-10T20:07:31Z

In reply to nevent1q…uv2p
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I recently got a R-8600, so I figured I could justify this and some really good feed cable ☺️

This will go in the attic for that exact purpose, broadband ...

2026-04-10T19:50:30Z

In reply to nevent1q…w2y6
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This will go in the attic for that exact purpose, broadband monitoring ☺️

OMG we need an IKEA name!!! Here’s one: BREDBAND (broadband) ...

2026-04-10T19:44:24Z

In reply to nevent1q…vvay
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OMG we need an IKEA name!!! Here’s one: BREDBAND (broadband) 😂😂😂

Diamond D3000 #hamradio #SIGINT ...

2026-04-10T19:22:02Z

Diamond D3000
#hamradio #SIGINT

I need a Bias-T which covers a wide frequency area, but also in ...

2026-04-09T15:24:04Z

I need a Bias-T which covers a wide frequency area, but also in the low end, sub MHz range for my LW loop antenna with LNA. Saw this one and decided to give it a go. Formally specified to 200kHz it has a -1dB at 100kHz which is really good 🤩
Below that it drops fast but that’s ok for my applications.
And I can use it for hydrogen line (1420MHz) experiments as well, win-win 🏆

#rfengineer #hamradio #testandmeasurement #rfengineering

I did exactly that before I shot the video. It’s gravity 🙂

2026-04-03T12:13:38Z

In reply to nevent1q…attq
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I did exactly that before I shot the video. It’s gravity 🙂

those were the days 🥰 That was (likely) due the the earths ...

2026-04-02T07:24:58Z

In reply to nevent1q…hl6u
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those were the days 🥰 That was (likely) due the the earths magnetic field, and not a gravitational pull of the electron beam ☺️

Did you know that crystal oscillators are orientation dependent? ...

2026-04-01T19:35:25Z

Did you know that crystal oscillators are orientation dependent? Well they are 😎

Albeit in the milliHz range for a 10MHz OCXO, the frequency change is completely measurable when you rotate the unit and change the crystals reference to earths gravity 🙂🙂

#rfengineering #hamradio #testandmeasurement

Dream come true - enjoy a decent ‘defoiling’ and power-up of ...

2026-03-25T20:15:52Z

Dream come true - enjoy a decent ‘defoiling’ and power-up of my new #ICOM IC R-8600 🥲🥳

#hamradio #SWL #SIGINT

below 5dBcat 😂

2026-03-19T16:07:39Z

In reply to nevent1q…fx92
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below 5dBcat 😂

Right after birth, the still blind ‘horn kitten’ seeks out a ...

2026-03-19T15:33:01Z

Right after birth, the still blind ‘horn kitten’ seeks out a place to hide, typically a horn antenna.
The antenna and cat forms a symbiosis, and grow together, until finally, around age 2, a fully grown cat and an L-Band horn settles a life long relationship.

Occasionally two kittens settles in the same horn, forming a ‘Vivaldi pair’ and they’ll stay together like that for the remainder of their life.

This picture is extremely rare - as David Attenborough was once quoted, “It’s absolutely astounding”

#antennas #kitty #rfengineering

you’re welcome, it was harder than I thought (although in ...

2026-03-11T21:12:08Z

In reply to nevent1q…rks5
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you’re welcome, it was harder than I thought (although in principle quite simple), because it’s so sensitive to external noise 🙂 But it shows that you can actually prove at home, that light has particle behavior - I find that really cool 😎🤩

Driving a LED at sub-nA currents, allows me to measure single ...

2026-03-11T19:02:43Z

Driving a LED at sub-nA currents, allows me to measure single photons, thereby proving that light acts like small energy bunches 👌🏼😎😎

See my previous video if you want to know more about the setup and the PMT (Photo Multiplier Tube)

#stem #physics #testandmeasurement #quantumphysics

+1 right back at you. 🙂

2026-03-11T15:43:00Z

In reply to nevent1q…exu3
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+1 right back at you. 🙂

Oh my… I finally have one… 😳🥲 What’s up with my luck ...

2026-03-11T09:46:13Z

Oh my… I finally have one… 😳🥲

What’s up with my luck these days 😃

#rfengineers will know what this is all about 🥰

#bestdayever #rfengineer #rohdeschwarz

absolutely 💯 One of the four threads is busted but I can fix ...

2026-03-11T06:14:33Z

In reply to nevent1q…z6xy
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absolutely 💯 One of the four threads is busted but I can fix that (they go into a closed cavity, not part of the chamber)

Lucky me! 😃 Came across this beauty, mint condition, at a ...

2026-03-10T21:12:00Z

Lucky me! 😃

Came across this beauty, mint condition, at a price which left little debate 🤌🏼🤩

I finally have a calibrated horn antenna 🥲

#rfengineering #hamradio #testandmeasurement #testgeartuesday

Purely out of instinct and how I understand nature, I’d expect ...

2026-02-22T11:28:15Z

In reply to nevent1q…2jej
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Purely out of instinct and how I understand nature, I’d expect it to decline when cooled. Things tend to slow down a lot at cryogenic conditions, but that’s just a gut feeling 🙂

I was asked elsewhere about any influence of external light, ...

2026-02-22T10:57:53Z

In reply to nevent1q…fw9q
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I was asked elsewhere about any influence of external light, here’s my answer 🙂

Built a test setup for my PMT tube, allowing me to bias an LED at ...

2026-02-22T10:55:03Z

Built a test setup for my PMT tube, allowing me to bias an LED at really low currents, hopefully catching single photons, or at least a very low count 🙂

Photo Multipliers are insane devices! 🤷🏼‍♂️🤯

This video is meant to explain the setup, stay tuned for my next video where I do actual measurements 🙂🙂

#stem #physics #electronicsengineering #testandmeasurement #quantum

That’s extremely kind (and trustworthy) of you 🙏🏼 I’m ...

2026-02-18T20:36:17Z

In reply to nevent1q…9f8f
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That’s extremely kind (and trustworthy) of you 🙏🏼 I’m exploring a bit of options here - then I might get back to you 🙂 After all, it’s ‘just’ a (photon counting) experiment in my private lab ☺️ Cheers

Regular frequency counter often have issues with non-periodicity, ...

2026-02-18T18:31:36Z

In reply to nevent1q…nqwc
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Regular frequency counter often have issues with non-periodicity, that’s why I’m looking for a real counter

oh that would cost me a vital organ… 😂 But I got a ...

2026-02-18T18:30:27Z

In reply to nevent1q…cqqw
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oh that would cost me a vital organ… 😂 But I got a suggestion elsewhere, that a discrete counter (74AC4040) could do it, then simply have some Arduino thingy do the math…

Fellow EEs, I need a universal counter which can totalize pulses ...

2026-02-18T16:11:24Z

Fellow EEs, I need a universal counter which can totalize pulses like these over a set time, fx. 1 second, and do statistics over over subsequent measurements… Any ideas? Amount of pulses during the test window is of stochastic behavior, but ranges from 20-40 per second to several thousands… Any ideas? 🙏🏼🙂

For an upcoming experiment, I need to know how accurate my ...

2026-01-24T19:21:45Z

For an upcoming experiment, I need to know how accurate my #Keithley 2400 is at nA outputs (God I absolutely love that box… 🥰), but I also wanted to see how well my 6.5digit GDM-9061 multimeter tagged along..

Enter the HP 3458A… 💪🏼😎

Connected them all in series and although the set point on the 2400 is a bit off from reality, it’s own current measurement is bang on. At 20nA 🤯😃 And the 9061 multimeter was in agreement as well, even at such low currents.

Ready for next step, stay tuned 😎😎

#electronics #testandmeasurement #rfengineer #electronicsengineering

Yup, I know the principle 🙂 Think I’ll stick with light for ...

2026-01-24T07:46:07Z

In reply to nevent1q…6ev5
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Yup, I know the principle 🙂 Think I’ll stick with light for now 👍🏼

😂 We’ve all been there ☺️ 73s

2026-01-20T17:25:58Z

In reply to nevent1q…vwza
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😂 We’ve all been there ☺️ 73s

Get a Siglent SDS1202X-E, when you’re ready to ramp up. It’s ...

2026-01-18T17:33:58Z

In reply to nevent1q…07cy
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Get a Siglent SDS1202X-E, when you’re ready to ramp up. It’s excellent value for money and really easy to use.
I had one once - sold it for a 4CH upgrade, but it’s a really decent allround scope.
You’ll hear ppl say ‘no one buys 2CH anymore’ but that’s BS. 4CH almost doubles the price and unless you’re really into the hobby (or moving towards a professional status), 2CH is by far sufficient. Best of luck 🤞🙂🙏🏼

very few, even vintage, scopes are single channel, but they’re ...

2026-01-17T10:10:01Z

In reply to nevent1q…crtw
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very few, even vintage, scopes are single channel, but they’re out there 🙂

At the night of the legendary capacitor explosion we also hosted ...

2026-01-17T08:54:47Z

At the night of the legendary capacitor explosion we also hosted a BYOD Oscilloscope night, where ppl could bring their instruments and learn more about them, common pitfalls, how to do basic measurements, more advanced stuff, etc.

Surprisingly many electronics enthusiasts don’t have an oscilloscope, and even more surprising, many don’t really know how to use the instrument they have.

The evening opened many new doors to the participants - I think everyone were happy 😃

#hamradio #electronics #electronicsengineering #rfengineer #testandmeasurement

in fact, you could argue it a rough day at work ...

2026-01-17T08:24:47Z

In reply to nevent1q…s88f
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in fact, you could argue it a rough day at work 🤷🏼‍♂️😂

not as bad as you would expect, it was a dried out paper ...

2026-01-16T15:09:50Z

In reply to nevent1q…8g4h
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not as bad as you would expect, it was a dried out paper capacitor 🙂

😂

2026-01-16T15:08:54Z

In reply to nevent1q…920g
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😂

certainly was 😆🎉

2026-01-15T07:24:59Z

In reply to nevent1q…sfn8
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certainly was 😆🎉

paper from the looks of it 🙂

2026-01-13T21:56:04Z

In reply to nevent1q…e2px
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paper from the looks of it 🙂

oh yes 😂 Once we established that everyone was ok, and we’d ...

2026-01-13T21:25:18Z

In reply to nevent1q…mkjh
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oh yes 😂 Once we established that everyone was ok, and we’d cleared the smoke, I looked at the three guys: they were covered in it! 🤣

Suddenly a loud bang from the lab at the local #hamradio club ...

2026-01-13T21:14:06Z

Suddenly a loud bang from the lab at the local #hamradio club ‼️ 💥🤯

Luckily nothing happened to the people in there, but I guess it’s safe to say that this vintage capacitor decided to quit its job 😂

Always wear safety glasses 🥽 when testing and troubleshooting #electronics, especially if it’s vintage gear where you have no knowledge of its state and health☝🏼

#electronicsengineering #vintageelectronics #vintagerepair

I bought a #Hamamatsu H7828 photomultiplier module, a ‘photon ...

2025-11-27T21:17:19Z

I bought a #Hamamatsu H7828 photomultiplier module, a ‘photon counter’. They’re insanely sensitive 😳

Seller knows what they’re dealing with and sealed it nicely in aluminum tape.

I left the tape mounted and put it in a box to screen the ambient light in my lab (which was already dimmed), then powered it on. It shows a ‘dark count’, noise that produces a certain level of ‘background’ pulses. Then I opened the box, just a little. And it’s visible!! 😳😳

A few photons, not many, still makes it to the detector, despite the aluminum tape sealing, it’s insanely sensitive 🤯🤯

I need to find a way to count the pulses and do some statistics on it, stay tuned for future experiments 🤓

#electronicsengineering #engineer #physics #stem #photon #photoncounting

I really had my doubts which one to get - so I ordered one of ...

2025-11-02T20:28:15Z

I really had my doubts which one to get - so I ordered one of each 😂

Plan to keep them both - they’re amazing 🤩

#hamradio #cw #cwops #begali

The Pico Technology TC-08 is dated, but it’s still going strong ...

2025-10-26T20:24:37Z

The Pico Technology TC-08 is dated, but it’s still going strong 👍🏼 With the optional terminal board, the thermocouple channels can be used to log either voltages or 4-20mA (industrial current loop).

I’m logging the discharge curve of a 9V Alkaline battery, using an OP-AMP as a voltage divider/buffer, as the terminal board is limited to +/-5V.

The software is really easy to use and is supported on several OS 😃

There are many voltage loggers out there, but if you already have a TC-08, the small terminal board is a really nice addition and an easy way to quickly log long-term measurements 🙂

#testandmeasurement #electronicsengineering #engineer #picotech #oicotechnology

Using a converter, mixing with 10MHz, I received SAQ Grimeton ...

2025-10-24T16:51:44Z

Using a converter, mixing with 10MHz, I received SAQ Grimeton today at 17.2kHz 🤩

Not my first, but definitely the best signal strength so far 😃

#hamradio #cw #cwops #saq #grimeton #saqgrimeton

They deliver surprisingly good instruments for the pricetag 🙂

2025-10-20T06:55:33Z

In reply to nevent1q…t5q0
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They deliver surprisingly good instruments for the pricetag 🙂

The #Fnirsi battery tester has a calibration option, but how ...

2025-10-20T04:59:57Z

The #Fnirsi battery tester has a calibration option, but how accurate is it out of the box?

Quite accurate, it would seem. Voltage measurement is precise into the mV range and my trusty old resistance standards are bang on 👌🏼😃

#electronicsengineering #testandmeasurement #electronicsengineer #battery #hamradio

Finally got the #fnirsi battery tester 🙂 It measures inner ...

2025-10-19T15:11:10Z

Finally got the #fnirsi battery tester 🙂
It measures inner resistance and voltage.

You can see how the resistance increases when the battery is depleted, that’s textbook material 👌🏼🙂

#electronicsengineering #testandmeasurement #rfengineer #electronicsengineer #batterytechnology

Forgot the high load test 🤷🏼‍♂️😂 Here you go ...

2025-10-04T19:26:12Z

Forgot the high load test 🤷🏼‍♂️😂 Here you go 👌🏼
#electronicsengineering #testandmeasurement

The LM73100 is almost a magical component: it functions as an ...

2025-10-04T19:13:28Z

The LM73100 is almost a magical component: it functions as an ‘ideal diode’ with just 30-40mOhm series resistance. At 5A it shows a bit of a positive temperature coefficient, so the loss is higher when it heats up, but still, it only has about 200mV drop at that load 😳

It gets warm, about 90C, but it’s still impressive for such a small surface mounted device.

I’ll be using it to charge batteries at max 3A, at which it remains stable at a much lower 50C 🙂

#electronics #electronicsengineering #engineer #testandmeasurement #fnirsi #dps150 #adafruit

Decided to test the input bias current of some different OP-AMPS ...

2025-09-24T20:10:25Z

Decided to test the input bias current of some different OP-AMPS at 5V input. The 741 does quite well at 30nA, the 5532 is quite higher, 189nA, still within spec., and the LMC662 maxes out my Keithley 2400, last digit just wiggles all over the place… Need to power up the 3458A and make a decent setup on a small PCB.. That’s another night ☺️

#testandmeasurement #electronics #electronicsengineering #voltnut #rfengineer #hamradio #hamr

there will be pictures 😎👍🏼

2025-09-21T19:34:06Z

In reply to nevent1q…6pfx
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there will be pictures 😎👍🏼

🥰

2025-09-21T19:32:20Z

In reply to nevent1q…6q75
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🥰

in fact, next weekend I’m going on a road-trip with friends for ...

2025-09-21T19:14:05Z

In reply to nevent1q…pvdv
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in fact, next weekend I’m going on a road-trip with friends for that purpose alone - can’t wait 🥰

for me POTA is all about S0 (or thereabouts) noise… I don’t ...

2025-09-21T19:12:16Z

In reply to nevent1q…6kg7
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for me POTA is all about S0 (or thereabouts) noise… I don’t consider POTA a contest, I love being QRP outdoors and /P so for me it’s a win-win 🙂

nice load btw - 1GHz?

2025-09-21T19:08:26Z

In reply to nevent1q…2rut
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nice load btw - 1GHz?

‘Show me your slugs!” 😂 God I love my little community ...

2025-09-21T19:08:03Z

In reply to nevent1q…2rut
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‘Show me your slugs!” 😂 God I love my little community here ☺️ Anyway, here we go:

Oh. I have a Bird as well, mint state, and a couple slugs with ...

2025-09-21T18:52:59Z

In reply to nevent1q…jrz3
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Oh. I have a Bird as well, mint state, and a couple slugs with it. Still looking for the one everybody wants: 2-30MHz 100W 🤷🏼‍♂️😂 I have the 50W, which actually covers me well since I’m mostly QRP, but occasionally I need to go higher, like this weekends SAC test 🙂

Amen to that 😂☺️🙏🏼🙏🏼

2025-09-21T18:48:58Z

In reply to nevent1q…7ruh
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Amen to that 😂☺️🙏🏼🙏🏼

I’m spineless 😂

2025-09-21T18:33:17Z

In reply to nevent1q…6gee
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I’m spineless 😂

😂

2025-09-21T18:32:56Z

In reply to nevent1q…8wa2
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😂

Pictures from #hamradio #SAC #CW contest. Participated as single ...

2025-09-21T18:29:03Z

Pictures from #hamradio #SAC #CW contest.
Participated as single ops, low power (<100W), TB-WIRES. Managed 15hrs at the radio - not too bad 🙂🙂

Admitted: Now I have enough RF power meters! 😂 But ...

2025-09-21T18:05:20Z

Admitted: Now I have enough RF power meters! 😂

But occasionally you strike luck and have to make a quick decision, which is why my Vintage 432A now has new friends 🙂

The probe for the Rohde@Schwarz NRVS covers to 6GHz and I scored an inline probe as well, which has a ceiling at 3 GHz. Neat!

The other two reaches 18GHz.

So who do you like more? 🙂🙂

BTW. Does anyone know how to enable display light on the NRVS? Can’t find a manual 🤷🏼‍♂️🤨

#rfengineer #rfengineering #electronics #testandmeasurement #hamr #hamradio

oh and yes, remote ctrl is fantastic, but also a discipline on ...

2025-09-20T08:22:38Z

In reply to nevent1q…xme8
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oh and yes, remote ctrl is fantastic, but also a discipline on its own and there’s only 24hrs a day🤷🏼‍♂️😂

The remote part is handled from this vintage module - it ends in ...

2025-09-20T08:07:23Z

In reply to nevent1q…ssp9
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The remote part is handled from this vintage module - it ends in an RJ45 port, but there’s a weird DB9 for ‘Ethernet setup’ .. I have absolutely no idea how it works… Could hook it up to a serial connection, maybe it’s a terminal/telnet interface 🤷🏼‍♂️😂

Ready for #hamradio #SAC #CW - listen for OZ1LQO. 100W single ...

2025-09-20T08:01:31Z

Ready for #hamradio #SAC #CW - listen for OZ1LQO. 100W single ops, TB-WIRES category 😎

I needed an accurate attenuator for a work experiment I wanted to ...

2025-09-19T08:13:15Z

I needed an accurate attenuator for a work experiment I wanted to do at home (recovering from a dental surgery — I’m fine 🙂) and a friend had this beauty taking up space 🤷🏼‍♂️🙂 (I have good friends).

Clearly hand built (sorry for the shaky video), made to sit in a test rack, remote controlled by the vintage Z80x CPU board. It’s quite flat in its frequency response (I had troubles with the VNA calibration, so you’re seeing cable and connector loss) and I made a couple spot checks at 3 and 6GHz, 1.5 and 2.5dB loss respectively.

Attenuation accuracy is within +/- 1dB.

This is quality vintage stuff, dated about 2003 from the onboard chips. Don’t you just love the Teledyne RF relays? 🥰

Oh, and it works way below the stated 2GHz, I tested it down to 10MHz and it was just fine 👍🏼

#rfengineer #rfengineering #frequencyfriday #hamr #hamradio #testandmeasurement

Thanks, that sure is a horrible footprint 😂 For my current ...

2025-09-18T09:07:22Z

In reply to nevent1q…6fld
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Thanks, that sure is a horrible footprint 😂 For my current application it’s somewhat overkill, but I might get a couple breakout boards from Adafruit to test 🙂

that’s true but it’s a lot more complex (and expensive) than ...

2025-09-18T07:45:38Z

In reply to nevent1q…zsnw
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that’s true but it’s a lot more complex (and expensive) than a simple diode 🙂 Care to share a schematic or reference to an application note? Thanks 😊

Occasionally it can be a good idea to add an in-line diode to ...

2025-09-17T19:28:56Z

Occasionally it can be a good idea to add an in-line diode to protect a power supply used to charge a battery.

You want the resulting voltage drop as low as possible which calls for a high-power Schottky diode. The STM STPS5L60 is a 60V diode, rated at maximum 5A continuously. As I’ll be charging at maximum 3A, I decided to test the voltage drop and resulting case temperature at that load.

I measured a 0.38V drop, resulting in about 1.15W dissipated - not bad 😃

The outer case temperature rose to about 57C which is fully acceptable and way below the diodes limits. And it’s touchable as well, which is nice.

So, charging a LiFePO4 battery for my #hamradio #SOTA and #POTA operations, I’ll set the supply to 15V, limit the current to 3A, and the battery’s built in BMS controller will handle the rest, easy! 👌🏼🙂

For the record, I always keep an eye on it when charging and I usually reduce the current by the end of the charge cycle ☝🏼

#electronics #electronicsengineering #hamr #testandmeasurement #rfengineer

Not yet, but I will try 🙂 Just wondering if there was anything ...

2025-08-31T05:52:20Z

In reply to nevent1q…hawr
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Not yet, but I will try 🙂 Just wondering if there was anything out there in public 🙂

Reported, blocked

2025-08-30T07:36:17Z

In reply to nevent1q…p6u8
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Reported, blocked

So is there anywhere I can find the construction details on the ...

2025-08-30T07:20:39Z

So is there anywhere I can find the construction details on the ‘Bluey’ portable 10GHz transverter? There are YouTube videos, but so far I haven’t been able to find a block diagram, schematics, etc.. 🤷🏼‍♂️🤔
Maybe it’s just a Kühne unit in a nice box..
#hamradio #hamr #rfengineer #SOTA

So many have tried and tested this little box, with all kinds of ...

2025-08-30T07:02:21Z

So many have tried and tested this little box, with all kinds of varying results, I thought I’d have a go myself .. 🙂

It’s really not too bad on the noise side and I won’t be using it at high loads for sensitive circuits anyway. PSU noise measurements have a lot of pitfalls, I’ve seen people being disturbed by their overhead (LED) bench light strips, wondering what was going on 😂🤷🏼‍♂️

Correct probe attachment and measurement bandwidth (most new scopes have a 20MHz option) is essential for tests like these.

A nice little addition to the lab, much more portable and quick-to-use than my bulky, linear, GW bench supply 🙂
#electronics #electronicsengineering #hamradio #hamr #testandmeasurement

In January, I bought two 10V references, based on LM399. I was a ...

2025-07-12T19:02:40Z

In January, I bought two 10V references, based on LM399. I was a bit skeptical on the design, following Marco Reps on YouTube does that to you 😂, but a teardown revealed quality components (Vishay precision resistors) and a decent circuitry and PCB layout.
I measured the standard deviation on the 10V output, using my 3458A, and I’ve done so monthly-ish ever since, leaving them powered all the time.
In March I added two more, unit 3 and 4.
Result so far: unit 1,2,3 are converging towards 1uV SDEV, unit 4 however (separate curve), started out sky-high, but it has now joined the ppm club 🤷🏼‍♂️😳
Someone mind telling me what’s going on? I mean, it’s wellknown that the noise drops over time, but why? What physical/chemical factors comes at play, causing this behavior?
#voltnuts #ppmgeek #electronicsengineering #testandmeasurement

I agree 🙂

2025-06-27T09:02:55Z

In reply to nevent1q…a3yt
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I agree 🙂

Thanks 🙏🏼🙂

2025-06-27T08:16:37Z

In reply to nevent1q…mced
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Thanks 🙏🏼🙂

thanks! That’s interesting information, would you have a ...

2025-06-27T07:31:51Z

In reply to nevent1q…sppd
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thanks! That’s interesting information, would you have a source? 🙂 Best 73

Well, based on the spacing alone, I doubt it’s hamradio. ...

2025-06-27T05:58:07Z

In reply to nevent1q…78ym
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Well, based on the spacing alone, I doubt it’s hamradio. Leaning towards some military stuff as they’re know to pollute our bands occasionally 🙂

Unusual FSK signal at the 40m band, spaced 7kHz. One carrier ...

2025-06-26T21:05:22Z

Unusual FSK signal at the 40m band, spaced 7kHz. One carrier sounds like broken CW, but once you listen to both, it’s clearly some data signal.. There’s another pair lurking around 7065kHz 🤷🏼‍♂️🤨 #hamradio #intruder

and here : https://techhub.social/@oz1lqo/113693191950760184

2025-06-08T12:25:56Z

In reply to nevent1q…jfzt
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and here : https://techhub.social/@oz1lqo/113693191950760184

It’s really quite a gem, and they’re a rare find. It’s ...

2025-06-08T12:24:37Z

In reply to nevent1q…w9fs
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It’s really quite a gem, and they’re a rare find. It’s surprisingly accurate, even to this day.
I tested it some months ago, have a look here: https://techhub.social/@oz1lqo/113678134364861216

always nice and cozy in your lab, I’m sure ...

2025-06-08T11:49:12Z

In reply to nevent1q…5wjd
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always nice and cozy in your lab, I’m sure 🤷🏼‍♂️😂

I needed a bit of distraction, so why not go ahead with the ...

2025-06-08T07:55:01Z

I needed a bit of distraction, so why not go ahead with the bi-yearly gear power-up 🙂

So today is the day where you power up your precious instruments you don’t use too often, thereby preserving the capacitors in power supplies, analogue circuitry, etc.

It doesn’t take long, an hour will do it 🙂⏰

#electronicsengineering #rfengineer #hamradio #hamr #testandmeasurement

Yesterday was #worldmetrologyday and thus, a perfect occasion to ...

2025-05-21T20:38:31Z

Yesterday was #worldmetrologyday and thus, a perfect occasion to do the monthly statistical readout of my four 10V references, based on the popular LM399.

Two of them arrived January 15 and has been powered since. A couple of months later, March 22, I added two more. The idea is, that the standard deviation (noise) of the 10V output should improve with time, lots of time 😂

Well, that is in fact what I see. Three of them are now at 1.15uV, 1.17uV and 1.45uV.
The fourth however, started out really high, 81uV 😳, but has since improved to 29uV in just two months.

I plan to keep doing this, - Let’s see what the rest of the year brings 🙂🙂

Long term plan: a 10V calibration transfer 👍🏼

#testandmeasurement #engineer #electronicsengineering #electronics

Today is #worldmetrologyday - celebrating the ingenuity behind, ...

2025-05-20T06:47:29Z

Today is #worldmetrologyday - celebrating the ingenuity behind, and the importance of, correct measurements.
Today is also the 150th anniversary of signing the meter convention 😃🎉🎉

Dense.. ☺️☺️

2025-05-03T21:10:00Z

In reply to nevent1q…cd8s
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Dense.. ☺️☺️

the Chemist nerd meets a physics/electronics/radio/antenna nerd ...

2025-05-03T20:48:19Z

In reply to nevent1q…rzrq
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the Chemist nerd meets a physics/electronics/radio/antenna nerd 😃 +1 follow my friend ☺️

in fact as I’m recently the happy owner of a lab grade laser ...

2025-05-03T17:56:58Z

In reply to nevent1q…wq9m
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in fact as I’m recently the happy owner of a lab grade laser driver, I can make sure a purple diode is at safe levels for Gin/Tonic experiments 😃😂👍🏼

wow, that’s a cool experiment!! Thanks a bunch ...

2025-05-03T17:34:23Z

In reply to nevent1q…86ad
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wow, that’s a cool experiment!! Thanks a bunch 👍🏼🙂🙂🙂

My acrylic tub contains a sugar solution which has been carefully ...

2025-05-03T17:33:12Z

In reply to nevent1q…wghz
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My acrylic tub contains a sugar solution which has been carefully designed to exhibit a gradient behavior, i.e. the sugar density is higher towards the bottom. The process takes about 24hrs. A laser beam is continuously sent through the solution horizontally. Offsetting the beam downwards, stil horizontally, will make it curve the way you see due to the increasing sugar density. The bottom of the tub acts like a mirror and reflects the beam upwards. It then curves back down for another reflection, and so forth.
Hope this explanation is of value 🙂

ahh yes, I know these layers well, being a radio amateur since ...

2025-05-03T17:06:09Z

In reply to nevent1q…ndzm
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ahh yes, I know these layers well, being a radio amateur since 1986 🙂 Appreciate your comment, I love the feedback and interaction I get here 👍🏼🙂

it’s more like what we know as a evaporation duct in the radio ...

2025-05-03T08:57:41Z

In reply to nevent1q…64ye
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it’s more like what we know as a evaporation duct in the radio world. As the sugar density (or atmosphere moisture) increases, the light (or radio signal) bends. In case of the radio signal, since the earth is round, the signal ends up curving along with the it, extending the range.