Rasmus "raek" [rɛːkʰ] SA5RJS

Python · Linux · Conlanging · Linguistics · toki pona · Handwritten Websites · Gemini (the protocol, not the AI) · Embedded · Software Toolsmith · Electronics · Amateur Radio · Homebrew Radios · Security · Programming Language Design · Electromagnetism · Astronomy · Physics · Linguistics · toki pona · Skeptical Mystic · Bass Clef · All over the place nerd.

Blog and links: https://raek.se/
Gemini: gemini://raek.se/
IRC: raek @ libera and quakenet
Amateur Radio: SA5RJS

Public Key

npub133kx3vtsccvrn4uxjn85wacm45uqglre8qz7z7tr86p6lhy0whsqmhfazx

NIP-05 Address

raek_at_tilde.zone@momostr.pink

Profile Code

nprofile1qqsgcmrgk9cvvxpe67rffn68wud66wqy03unsp0p093naqa0mj8htcqpz3mhxue69uhhyetvv9ujuerpd46hxtnfduqs6amnwvaz7tmwdaejumr0dswf2lk6

Publishing to

relay.damus.io

nos.lol

Author Public Key

npub133kx3vtsccvrn4uxjn85wacm45uqglre8qz7z7tr86p6lhy0whsqmhfazx

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Last Notes

2025-10-05 17:02:01 UTC

Got two #conlang inspiration books today!
https://media.tilde.zone/media_attachments/files/115/322/626/658/247/987/original/0aa3198050e5eb80.jpg

2025-04-06 21:18:10 UTC

Soldersmoke DCR build: mixer/diplexer done. i tested it with an external audio amplifier (a.k.a mic input of a computer audio interface). It works! Now the band pass filter and audio amp modules are left to build.
#AmateurRadio #HamRadio #electronics
https://media.tilde.zone/media_attachments/files/114/293/090/145/051/197/original/89aedbba9c4e00b4.jpg

2025-03-27 10:19:28 UTC

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mi ante e lipu tu ni:
gemini://raek.se/toki-pona/
gemini://raek.se/links/recommendations.gmi
sina jo e lipu kepeken toki pona la, mi wile jo e linja tawa ona! (sina lipu kepeken toki Epelanto la, mi sona e ona.)

2025-03-26 18:02:25 UTC

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The blog HTML is generated from markdown files using a few scripts: https://github.com/raek/blog.raek.se/

2025-03-26 18:01:15 UTC

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I'm hosting the blog and the capsule on my VPS. Links:
https://blog.raek.se/
gemini://raek.se/

2025-03-26 16:02:47 UTC

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For the last month or so I've been using I the 'offpunk' browser to subscribe to blogs on the web and capsules on Gemini and read the posts in the text interface. So I use offpunk both as a https/gemini feed reader and a Gemini browser.
I also use Lagrange as a browser to read the Antenna feed.

2025-03-23 14:37:43 UTC

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ike a!
linja pi lipu moli li lon lon seme?

2025-03-18 19:22:28 UTC

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Cool! I didn't know about that one!
I once made a "why doesn't this snippet of code misbehave" puzzle with these lines in it (which should be in monospaced font for best effect):
#define ALPHA(f) ((long int) f + 0)
#define BETA (f) ((long int) f + 1)
#define GAMMA(f) ((long int) f + 2)
Until now, that was the only example of significant whitespace I knew about!

2025-03-15 21:13:27 UTC

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This is the schematic.
https://media.tilde.zone/media_attachments/files/114/168/509/011/367/974/original/52cf237e4798a32d.png

2025-03-15 21:06:11 UTC

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Lol! No, this is the VFO...

2025-03-15 20:52:03 UTC

The joy of oscillation!
I turned on the first module of the Soldersmoke direct conversion receiver challenge radio. It worked!
#AmateurRadio #HamRadio #SolderSmoke #SolderSmokeChallenge
https://media.tilde.zone/media_attachments/files/114/168/418/934/673/321/original/6a9136d84a6c4879.jpg
https://media.tilde.zone/media_attachments/files/114/168/419/357/719/013/original/c3eacfe3e5d23c2f.jpg

2025-03-10 15:23:46 UTC

Maybe it's finally time for me to give learning #esperanto a go...

2025-03-10 09:39:23 UTC

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Also, running "sudo dmesg -w" in a terminal in the background to see if the USB device resets would also be interesting.
Another idea: what power source do you use? Could it be a brown-out of the USB during TX?

2025-03-10 09:35:56 UTC

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Could it be RF getting into the USB port and making the USB device reset? For me WSJT-X falls back to the internal mic when I unplug the USB cable of my QMX.
Would be interesting to know if adding a ferrite to the USB cable makes a difference...

2025-03-09 09:12:03 UTC

Just became aware of this RD engineering treasure trove: https://www.minicircuits.com/applications/application_notes.html
#AmateurRadio #HamRadio #RfElectronics #RF #electronics

2025-03-09 08:12:16 UTC

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I know what that's like! Hang in there.
I wish you happiness and fulfillment in playing the long game!

2025-03-07 22:36:04 UTC

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The Mini-Circuits article was a very good read.Thanks!

2025-03-07 22:13:58 UTC

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There's this item on AliExpress too: https://www.aliexpress.com/item/1005004235791904.html
I will buy this one from Electrokit, since it's a store in my country: https://www.electrokit.com/bnc-hona-chassi-silver-25x25mm

2025-03-07 19:17:10 UTC

I want to replace this UHF / SO-239 connector with a BNC one. Does anyone know if panel mount BNCs with one inch wide flanges exist?
#AmateurRadio #HamRadio
https://media.tilde.zone/media_attachments/files/114/122/753/263/710/067/original/f6a17a871db9bcae.jpg
https://media.tilde.zone/media_attachments/files/114/122/753/631/562/969/original/8cfe3d89b48da9ce.jpg

2025-03-07 12:35:46 UTC

Dear radio frequency engineering fediverse,
Do you know of a good article that describes how to conduct a two-tone test to measure intermodulation properly? I understand the basics and I know to generate the test signal and how to measure the result on a TinySA. However, I don't know how to determine if my test signal is clean enough, has a reasonable power level, etc. In other words, I don't trust that I understand my test setup enough to trust my results..
Do you have any good links?
#AmateurRadio #HamRadio #RF #electronics #RfElectronics

2025-03-02 14:40:29 UTC

I'm listening to the...
https://media.tilde.zone/media_attachments/files/114/093/347/711/882/204/original/9c21ac18ceb5361d.png
https://media.tilde.zone/media_attachments/files/114/093/352/378/619/355/original/bc1a7f1a2ecf7264.jpg

2025-03-01 20:06:10 UTC

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And today I manged to have two FT4 QSOs using the BITX40 and manually toggling the PTT switch!
https://media.tilde.zone/media_attachments/files/114/088/970/012/649/303/original/2468b352a1561b7e.jpeg

2025-02-28 22:07:51 UTC

Tonight I performed the "Digital BFO Modification" on my BITX40.
https://github.com/amunters/bitx40-raduino-v2/blob/master/operating-instructions.md#digital-bfo-mod
The mod adds USB mode to the rig (which only did LSB originally). It also allows me to calibrate the BFO frequency to align it with the actual pass band of the crystal filter (each individual is slightly different). It also changes from low side injection to high side injection, which makes the 7.2 MHz birdie go away as well as the interference from the 7.2-7.3 MHz 41m broadcast band getting folded over into the 7.0-7.2 MHz 40m amateur radio range.
The mod was successful and I even managed to decode FT8 received from the newly gained mode!
#AmateurRadio #HamRadio #electronics
https://media.tilde.zone/media_attachments/files/114/083/762/158/215/768/original/333db1972d557873.jpg
https://media.tilde.zone/media_attachments/files/114/083/788/001/798/544/original/12dec5e84f5a7d5e.jpg
https://media.tilde.zone/media_attachments/files/114/083/788/550/590/496/original/026ec5b3a7ecd5ef.jpg

2025-02-27 21:44:02 UTC

Decided to compare the filters of the QMX and the BITX40 on reception. I used my AliExpress noise source and recorded some audio in Audacity.
The QMX filter is impeccable. Like a brick wall. Totally flat between 150 Hz and 3500 Hz, pretty much.
The BITX40 one though... 😅 Passband is pretty much limited to 500 Hz to 1500 Hz and isn't very flat at all. More like a round hill.
#AmateurRadio #HamRadio #electronics
https://media.tilde.zone/media_attachments/files/114/078/015/326/616/207/original/e8f3c442730f8d65.png
https://media.tilde.zone/media_attachments/files/114/078/016/041/726/888/original/e252601015e6e6c8.png
https://media.tilde.zone/media_attachments/files/114/078/016/603/201/551/original/fa786a651aa1bbb9.png
https://media.tilde.zone/media_attachments/files/114/078/017/243/624/324/original/aed13a2b47db43c6.png

2025-02-27 13:25:10 UTC

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Since Obsidian stores its data as ordinary text files I use Syncthing to sync my vault between Linux, Android and Windows. It works like a charn!

2025-02-25 19:34:23 UTC

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I think it looks all right? (See ALT text.)
https://media.tilde.zone/media_attachments/files/114/066/190/670/687/189/original/eb8aa04ebc4ff37b.png

2025-02-25 19:15:35 UTC

This "20 dB" attenuator is very consistently -32.4 dB across HF. It remains a mystery to me why.
#AmateurRadio #HamRadio #electronics
https://media.tilde.zone/media_attachments/files/114/066/119/924/260/287/original/c013b7463c1a4798.jpg

2025-02-24 22:13:03 UTC

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sitelen pi lipu li ni:
# sewi li kule ale
tempo esun tu la, jan lili tu mi li pilin jaki lon insa uta lon insa kute.
mi wile lape. mi wile pali. mi wile toki e jan pona mi.
tempo ni la, jan lili mi pilin pona.
open pi tempo suno ni la, mi en jan lili mi awen lon supa monsi. tempo lete li pini lon ma.
suno open tawa sewi. sewi li pimeja, li loje pimeja, li loje, li loje jelo, li jelo, li jelo laso, li laso. sewi li kule ale. mi pilin e ni, mi sona e ni: ale li pona.

2025-02-24 22:08:13 UTC

ma Kemini la, mi pali e lipu sin ni: "sewi li kule ale"
gemini://raek.se/gemlog/2025-02-25-sewi-li-kule-ale.gmi
#TokiPona #Gemini #GeminiProtocol

2025-02-21 21:57:10 UTC

Assembled a BNC pigtial cable with a right angle connector for the first time today. It was easy to see and reach everything due to the "access hatch" on the top!
#AmateurRadio #HamRadio #electronics
https://media.tilde.zone/media_attachments/files/114/044/098/828/137/337/original/aaffae05b12c817c.jpeg
https://media.tilde.zone/media_attachments/files/114/044/099/757/533/598/original/8dc2a148073c7be0.jpeg

2025-02-21 21:34:59 UTC

New blog post:I Guested The European Ham Radio Show
gemini://blog.raek.se/2025/02/21/i-guested-the-european-ham-radio-show/
https://blog.raek.se/2025/02/21/i-guested-the-european-ham-radio-show/
#AmateurRadio #HamRadio #gemini #GeminiProtocol
https://media.tilde.zone/media_attachments/files/114/044/019/086/170/548/original/cd075c67ab7ccf57.png

2025-02-17 19:46:55 UTC

Now all my 56 kindle books are dowloaded and safely backed up, stripped of DRM.

2025-02-17 15:35:06 UTC

If you "own" Kindle books, download them while it is still possible: https://goodereader.com/blog/kindle/amazon-removing-download-and-transfer-on-the-kindle-feb-26th

2025-02-09 20:34:08 UTC

The European Ham Radio Show invited me as a guest to their show next week! (2025-02-16 19:00 UTC) I'm honored, starstruck and a bit nervous!
https://youtube.com/clip/Ugkx34kpP-xL6iZnbxwqST26UGkTS2woEFUb
#AmateurRadio #HamRadio

2025-02-09 14:48:53 UTC

I copied today's #Morsle at 35 WPM! https://morsle.fun

2025-02-06 06:41:31 UTC

I copied today's #Morsle at 40 WPM! https://morsle.fun

2025-02-04 21:34:12 UTC

New video! "My first home-made radio receiver"
YouTube: https://youtu.be/bYSZhNaHaAc
MakerTube: https://makertube.net/w/4C6cg3L6CY3GgB3iXzRPwo
#AmateurRadio #HamRadio #electronics

2025-02-04 06:36:30 UTC

I copied today's #Morsle at 35 WPM! https://morsle.fun

2025-01-31 21:13:38 UTC

I might have built a direct conversion receiver from a signal generator, a mixer, and an audio interface...
#AmateurRadio #HamRadio #electronics
https://media.tilde.zone/media_attachments/files/113/925/023/617/270/107/original/81bea678a0221560.jpeg

2025-01-29 16:52:04 UTC

New RF toy in the mail: a Mini-Circuts ZAD-2H mixer.
https://www.minicircuits.com/pdfs/ZAD-2H_SPEC.pdf
#AmateurRadio #HamRadio #rf #electronics
https://media.tilde.zone/media_attachments/files/113/912/621/088/500/186/original/8571097e8c49119c.jpg
https://media.tilde.zone/media_attachments/files/113/912/621/643/545/173/original/2da7c9d0f5bd7ef0.jpg

2025-01-27 12:45:45 UTC

I just discovered this treasure trove: "Basic Linear Design" / "Linear Circuit Design Handbook"
It's available for free on Analog Devices' website!
https://www.analog.com/en/resources/technical-books/linear-circuit-design-handbook.html
#electronics #AmateurRadio #HamRadio

2025-01-26 13:56:23 UTC

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You are right! That should work. The duration of each bit transfer is 1.25 us, I think.

2025-01-26 12:13:05 UTC

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There's a similar individually addressable RGB LED commonly marketed under the name "Dotstar". It uses separate data and clock wires, so the microcontroller is free to shift out the bits in whatever tempo it likes, unlike the Neopixels which have hard timing constraints.
If it's an alternative to you to switch LED type, then this might simplify things a lot for you.

2025-01-19 22:56:48 UTC

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7) Some things on the to-do list
So far I've run into some problems that probably need to be solved for me to be able to use this amp with my 7W BITX40 to get 20 - 50W SSB.
Get a more capable power supply. The one I ordered is on its way.
Output low pass filter. I have one built with T37-6 toroids, but I would like to have one with larger T50-6 toroids instead. I need to order suitable capacitors.
Lower feedback resistors. As usual, F5NPV provides great advice. The kit comes with 150 ohms, but I want to try with 100 ohms or 47 ohms to get better linearity (at the cost of lower output power).
Add source degeneration resistor and capacitor? Another way to add negative feedback to get better linearity, I think. Try what F5NPV and NA5Y did.
Add temperature compensation. I don't know exactly what to do here. I like a different bias circuit that I saw in one a video from Charlie Morris ZL2CTM. It had a current source and two diodes for each MOSFET.
Make a power attenuator for use on the input. This requires me to first figure out the suitable input power to drive the amp.
Wire up the fan. The heatsink comes with a fan. I just haven't used it yet.
Add temperature switches. I have 40 °C NO, 100 °C NC, and 120 °C NC temperature switched. The idea is to used them to turn on the fan (when above 40 °C) and kill the bias (when above 100 °C or 120 °C). I don't know how to fit them to the heatsink at a proper place yet, though.
Fix the BFO / crystal filter alignment on the BITX40. Currently, the high side of the passband seems to only be about 1.5 kHz instead of somewhere like 2.5 - 3.0 kHz. This is a know problem and I know of ways to fix it. (Add tuning capacitor to the BFO, or disable the BFO and use an output from the Si5351 instead.)

2025-01-19 22:38:48 UTC

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6) More power measurements, at two bias levels
I wanted to know how the input power and gate bias voltage together affected the output power. So I ran some tests for two bias levels. The first series of tests were made with 38 mA total quiescent current, so about 8 mA Id for each FET. The board draws 22 mA with zero drain current. The second series of tests were made with 64 mA total quiescent current, so about 21 mA drain current per FET.
The results can be seen in the table in the picture. I might edit this post later and type it to text. See the ALT text for definitions of the columns.
Since the current (and output power) changed over time, I read the meters some seconds (maybe 5) after I turned on the input signal. The values varied a lot, so these measurements are not super reliable.
Also, the power supply seems to current limit about 6 A. It's a 4.5 A power supply anyway, so the results at these levels are doubly unreliable.
https://media.tilde.zone/media_attachments/files/113/857/396/043/992/824/original/eff668f4c50a0b68.jpeg

2025-01-19 22:28:19 UTC

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5) Second test, where thermal runaway was very noticeable
I let the amplifier run with constant 13.2 V power supply, fixed gate bias voltage, and constant 0.2 W input power. The transistor tabs reached 70 °C in about a minute. The current consumption kept increasing.
This is in line with what F5NPV wrote about on his blog and @npub1v2z…0xqq pointed out here on mastodon. The bias circuit doesn't have any temperature compensation. So this is to be expected!
Links to YouTube and MakerTube videos:
https://youtu.be/kbxbTp3CwPo
https://makertube.net/w/5Nx4uXhbry3zhF468iNwru
#AmateurRadio #HamRadio #electronics
https://media.tilde.zone/media_attachments/files/113/857/373/357/724/154/original/1524e4ba5cd7b12d.png

2025-01-19 22:23:41 UTC

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In that setup, did you use any thermal compensation in the gate bias circuitry (like thermally coupled diodes, or something like that)?

2025-01-19 21:21:19 UTC

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4) First Test
I hooked up a current meter in series with the power supply and started to tweak the gate bias. The board draws 22 mA with the bias completely off. I turned the potentiometer until the current reached 42 mA, which should mean that each FET get about 10 mA of current.
I tested with the PA connected to the 13.2 V power supply and a few different power levels:
* 0.08 W in, 0.51 W out, (current not recorded)
* 0.16 W in, 4.07 W out, 2.3 A
* 0.26 W in, 11.0 W out, 3.6 A
* 0.51 W in, 28.8 W out, 5.8 A
The harmonic content was pretty terrible, as expected. I haven't added any low pass filter on the output yet. I've also heard that lower gate bias means more crossover distortion and non-linearity, so that makes sense.
https://media.tilde.zone/media_attachments/files/113/857/091/263/667/674/original/0399f7ef4a5e7898.jpeg

2025-01-19 21:01:06 UTC

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3) Signal Generator
My options for generating the input signal are basically by BITX40 and my QMX. The BITX40 has a trimpot for its PA driver. But instead I went with the QMX and used its "SWR meter" mode.
The QMX lets you adjust the SWR test output power as a percentage of the voltage used for full power. So "100%" is full power, but "50%" is a quarter of full power (due do P∝V²). I measured the power for various settings using my oscilloscope (12.0 V, 7.100 MHz):
* 10%, 5.8 Vpp, 0.08 W, 19.2 dBm
* 20%, 10.1 Vpp, 0.26 W, 24.1 dBm
* 30%, 14.2 Vpp, 0.50 W, 27.0 dBm
* 40%, 18.6 Vpp, 0.86 W, 29.4 dBm
* 50%, 22.8 Vpp, 1.30 W, 31.1 dBm
* 60%, 27.0 Vpp, 1.82 W, 32.6 dBm
* 70%, 31.0 Vpp, 2.40 W, 33.8 dBm
* 80%, 35.2 Vpp, 3.10 W, 34.9 dBm
* 90%, 39.2 Vpp, 3.84 W, 35.8 dBm
* 100%, 42.6 Vpp, 4.54 W, 36.6 dBm
I also looked at the QMX output on the TinySA Ultra spectrum analyzer. There weren't any visible harmonics at all, so I trust that this signal is suitable as a test signal.
https://media.tilde.zone/media_attachments/files/113/857/024/638/161/881/original/d0ab2c3e093b2985.jpeg

2025-01-19 20:16:13 UTC

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2) Power Supply
The kit states "13.8 V" on its schematic (the "standard" amateur radio voltage), so I'll use about that voltage for testing.
The power supplies I own are a bit limited. My HP E3631A is adjustable, but can only put out 1 A.
I have a fixed 13.2 V (so not quite 13.8 V) power supply that can deliver 3.5 A continuously / 4.5 A intermittently. It's what I've used so far.
During the tests, I managed to pull about 6 A pretty early on, so a new power supply is needed. I ordered a new one from AliExpress called "PS30SWVI" (Power Supply, 30 A, Switching, sixth generation). It even have double Anderson powerpoles on the front! It should arrive in about 2 weeks from now...
With the new power supply I should be able to adjust the voltage and have plenty of current available. My only worry is that it doesn't have any settable current limit, but I guess that I could ad a fuse in series.
https://media.tilde.zone/media_attachments/files/113/856/848/475/248/924/original/e22af96b3711e203.jpeg
https://media.tilde.zone/media_attachments/files/113/856/851/444/556/360/original/d07fecd45b19d383.webp

2025-01-19 20:05:05 UTC

⚡ MINIPA70 Test Thread! 🧵
The board is populated and does not put out smoke when powered up. So what's next?
As I see it, the power amplifier has three main parameters that I need to find an optimal value for:
* Power supply voltage
* Gate bias voltage
* Input power level
For each point in this three-dimensional space, I get the following resulting values:
* Output power
* Harmonics power levels
* Intermodulation distortion
* Current consumption
* Temperature
I have some reasonable starting points for the three parameters I need to tweak. A blog post by F5NPV has been invaluable for me, and in it he suggests good values for all the parameters.
https://f5npv.wordpress.com/irf530-mosfet-amplifier/
#AmateurRadio #HamRadio #electronics
https://media.tilde.zone/media_attachments/files/113/856/795/553/948/056/original/f847bba97819504f.png
https://media.tilde.zone/media_attachments/files/113/856/799/164/209/808/original/76f118c5bc9b1b75.jpg

2025-01-19 17:29:45 UTC

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I will post about the last days' tests later this evening when the kids are asleep and the chores are done!
https://media.tilde.zone/media_attachments/files/113/856/195/646/669/279/original/4c6cbe445200980b.png

2025-01-17 18:34:37 UTC

Got some power amplifier components in the mailbox:
• Switch that closes when hotter than 40 °C
• Switch that opens when hotter than 100 °C
• Switch that opens when hotter than 120 °C
• 2 × BN43-7051 ferrite binocular cores
• 10 × BN43-202 ferrite binocular cores
https://media.tilde.zone/media_attachments/files/113/845/117/501/233/684/original/e739a6b14836501c.jpg

2025-01-08 22:42:14 UTC

Tried a thing that has been on my to-do list for ages: listening to the signal that the BITX40 puts out! Here I transmitted into a dummy load and let the QMX pick up the RF using a small wire.
Here's an audio recording: https://raek.se/dump/bitx40_audio_test.mp3
A good thing is that the BITX40 both has a trimpot for the IRF510 bias *and* for pre-driver gain. That way I should be able to transmit at power levels below 7 watts too. The MINIPA70 power amp I'm building can't handle 7 watts on it's input, IIRC, so it's great that I can turn it down a bit.
#AmateurRadio #HamRadio
https://media.tilde.zone/media_attachments/files/113/795/108/088/087/674/original/9e55e13ad2dfe55d.jpg

2025-01-07 22:03:18 UTC

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Maybe later this week I'll have the FETs in place with a heatsink so that I can tweak the bias.
I also have to find a suitable power supply. And probably an input attenuator of I'm going to be able to use/test the PA with the BITX40 (7W output).

2025-01-06 21:20:07 UTC

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10) Added transformer wires and performed lots of measurements
The measurements can be seen in this spreadsheet (screenshots added to this post for convenience): https://docs.google.com/spreadsheets/d/1481s1TLiWwiSgU1UrxgSDXqTYwXUrslObALEj7EQkOw/edit?usp=sharing
Most of these measurements were performed on yesterday's live stream on YouTube: https://www.youtube.com/live/wQLbCVtNCCQ
I measured both transformers at all thee windings with all the other windings open and shorted. I also measured the two "tube" windings in series as separate entries.
Any interesting patterns? Tell me if you find any!
So far I've seen that the one tube doesn't "see" whether the other tube is shorted or not, *except* when the wire joining the tubes is shorted. Others in this thread has argued that the coupling between the two tubes are so low that the halves of each transformer could be seen as its own transformer, only connected in series by the wire winding.
#AmateurRadio #HamRadio #electronics
https://media.tilde.zone/media_attachments/files/113/783/453/501/078/219/original/f08c074a31c08dca.jpeg
https://media.tilde.zone/media_attachments/files/113/783/456/351/959/822/original/bf9af1815e02370e.png
https://media.tilde.zone/media_attachments/files/113/783/458/734/300/902/original/5fe0f1bdc645c427.png

2025-01-06 16:00:08 UTC

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How do you define "primary"? I always assumed it meant "input side", but from context I assume you mean the "wire" side (as opposed to the "tube" side).
If tube B is open and the wire side is terminated into a 50 ohm antenna, then surely the tube A side doesn't see 25 uH anymore? 25 uH is what you see when the antenna is unconnected, right?

2025-01-05 17:30:24 UTC

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Since last night the project looks like the attached pictures (haven't posted these pictures yet).
What measurements are you interested in? Measure one tube with A) yellow wire open (already did that, I guess) and B) yellow wore shorted? Any more? Maybe measure the yellow wire with the "tube winding" shorted/opened.
I need to measure this before soldering the yellow wires later tonight. 😄 Won't be until about 21:00 CET when the kids are asleep and the chores are done.

2025-01-03 11:17:29 UTC

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Have you checked out Marginalia? https://search.marginalia.nu/

2024-12-30 07:55:15 UTC

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Oops! That should have been 5.6 ohms. 50 ohms divided by 9.

2024-12-29 15:48:28 UTC

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3) The kit is not complete. For instance, it does not come with a heatsink or an enclosure. Instructions and a schematic were not included either. And I know the "70 watts" in its name is not realistic.
But I think the kit can be a useful first PCB for me to experiment with HF power amplifiers. There are a lot of tinkerers who have built this before and it's easy to find blog posts and videos showing how to build and test it. So this is a well beaten path and I'm in good company!

2024-11-26 07:56:44 UTC

Hey, there's another ham (@npub1zft…c7tn) who has uploaded SAQ-related videos to Makertube!
https://makertube.net/w/wh3bkKN4eUrVJezwHZfxk3
It's curious that whenever I think that I'm the only one interested in niche topic X in another unrelated niche place Y, there always seem to be someone else there with the same overlap of interests...
#AmateurRadio #HamRadio #SAQ #Grimeton

2024-10-01 16:50:51 UTC

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It turned out I got their callsign wrong. It was supposed to be "IR2RMAG"! I listened back to the recorder audio. The other station misheard my callsign as "SA5WJU"...
Now that I think about it I actually remeber seeing that on the QMX decoder display, but I didn't trust that the QMX "knew better" than the other operator.
Mistakes happen. I'm glad that I recognize when someone else repeats my callsign. But I think I need to pay attention and make sure all the letters are correct too. That'll come with time, I'm sure.
#AmateurRadio #HamRadio #CW #MorseCode #morse

2024-10-01 12:15:15 UTC

Made two #CW QSOs today! Now I have three in total.
20m is not very noisy at my QTH, so I could use the QMX to help me decide the #MorseCode. I responded to the other person's CQ with a simple "BK RR UR 599 599 BK" in both cases.
In the second contact I used the PoLo #POTA spots tab to find the operator. It's very convenient to have the spots in the logger, because PoLo allows you to just tap the spot to fill in the callsign, band, mode, frequncy and POTA reference into the new log entry automatically!
This time I used the Morserino "CW practice gadget" as my (touch) CW keyer. I've gotten used to the touch keyer and I quite like it!
#AmateurRadio #HamRadio #morse
https://media.tilde.zone/mastomedia/media_attachments/files/113/232/064/590/874/790/original/9b6ccba5d9ac66b3.png

2024-09-23 13:27:12 UTC

Dear amateur radio fediverse,
I have just started to read about Winlink. It seems like there are multiple RF protocols in use. I have a QRP Labs low bands QMX and want to know if it's possible to work Winlink using it, preferably from Linux? (It only supports modes that do not send multiple tones simultaneously.)
Do any of the "RF access" protocols used by Winlink (AX.25? PACTOR? VARA?) have this single-tone property?
I also saw that some of the protocols are proprietary. That doesn't sound too good for portability...
Is there any combo of mode and software this FLOSS-loving amateur should check out?
#AmateurRadio #HamRadio #Winlink #QMX