@ftg@mastodon.radio
@ftg@mastodon.radio avatar

ftg

@ftg@mastodon.radio

Radio/Electronics/Telecom Geek.
He/him.
youtube.com/oh2ftg
prkele.prk.tky.fi/~ftg/
twitter.com/2ftg1

This profile is from a federated server and may be incomplete. Browse more on the original instance.

gsuberland, to random
@gsuberland@chaos.social avatar

Bored and a bit too tired to carry on playing Dyson Sphere Program, so ask me anything. Electronics, lighting, lasers, colourimetry, Windows internals, security, whatever.

ftg,
@ftg@mastodon.radio avatar

@gsuberland
Ah.
RF root category.
Sort by price, cheapest first.
And then it's time to do discoveries across the first thirty pages.

ftg,
@ftg@mastodon.radio avatar

@gsuberland
Any idea how hard to softcore and hardcore PCIe IP cores are to use on Lattice LIFCL-40 from the CrossLink-NX series?

Arya Voronovas m.2 and PCIe article series have made some old project ideas resurface.

ftg, to hamradio
@ftg@mastodon.radio avatar

Huh, did you know that you can still get new manufacture Bell-202 compatible modem chips?

Product page: https://www.mouser.fi/ProductDetail/CML-Micro/CMX867AE2?qs=unwgFEO1A6tjwRkWjln%2F6g%3D%3D
Cheaper than FX614 on ebay.

Datasheet: https://www.mouser.fi/datasheet/2/976/CMX867A_ds-1627032.pdf

azonenberg, to random
@azonenberg@ioc.exchange avatar

Reworked all the bridges on the ESD diodes that I found during initial visual inspection, and tidied up a few bulk caps.

Did continuity tests to sanity check on each power rail and nothing is shorted.

Gonna start populating the front side after the little one goes to sleep. Should go faster than the back since it's mostly large ICs not hundreds of 0402s.

ftg,
@ftg@mastodon.radio avatar

@azonenberg
This whole thread was a delight to read.
Very interesting to see the bring up on a rather complex homebrew project.
The well structured approach does make it look far less daunting than I previously considered.

flexghost, to random
@flexghost@mastodon.social avatar

Twitter is now paying people to spread hate

Reminder: if you’re still on Twitter—your presence and your interactions generate revenue. You’re literally funding the alt right.

🏳️‍⚧️🏳️‍🌈🇺🇸

ftg,
@ftg@mastodon.radio avatar

@flexghost
Yeah I think it is over for me on twitter.
With this shit one cannot even passively take part.
Even with adblockers and tweak new twitter or whatever.
It all contributes to this.

I wonder if is possible to link specific advertisers to specific accounts getting paid.

ftg, to hamradio
@ftg@mastodon.radio avatar

Haha! The receive local oscillator locks.

ftg, to random
@ftg@mastodon.radio avatar

The controller PCB from an Amazfit model A1702 smart watch.
Did this to see what the screen in it was and if it could be re-used with a decent amount of effort.
The shiny WLCSP chip seems to be a STM32L476JE and that's the one running the show in it.
The chip next to it is a 25LQ64CW 64Mbit SPI flash.

ftg,
@ftg@mastodon.radio avatar

Here is the other side with all the connectors.
The shiny thing is a 16.00MHz oscillator for the Dialog made BLE radio, that has it's own Cortex-M0 core as well.
The tiny spring pin at the top seems to connect the 2.4GHz BLE radio to the case, to use the whole top of it as an antenna.

ftg, to random
@ftg@mastodon.radio avatar

My 2.4GHz downconverter runs UNIX.

ftg,
@ftg@mastodon.radio avatar

@HopelessDemigod UHF.

The chip in this 802.11b card has nominal 200 - 600 MHz IF bandwidth.
I'm converting the balanced output to unbalanced with some random balun I pulled from a scrap Nokia 2110.

Original IF was around 374 MHz.

ftg,
@ftg@mastodon.radio avatar

@recursive @HopelessDemigod
Hehe.
I did the usual and popped the can in it.
And to my delight discovered that it was was a nice old school superhet based on chipset, so a nice 374 MHz IF.
So I removed the saw and tapped the IF port via a balun.

ftg, to random
@ftg@mastodon.radio avatar

Just about the only thing a handbook is good for.

JennyList, to random
@JennyList@mastodon.social avatar

I'm not going to this year, even though I could easily get a ticket even now.

Yes, the tickets are expensive, but it's really their idea of what makes a hacker camp differs from mine.

Also, mixed toilets and showers are not some activist freedom shite, they're creepy. Even the ladies showers in the shower wonderland had an open changing area. No thanks.

Find the smaller camps folks, they're way more rewarding.

ftg,
@ftg@mastodon.radio avatar

@JennyList
That and the fact that they do continue inviting people like jacob appelbaum.

EposVox, to twitter
@EposVox@glitch.lgbt avatar

Can’t view tweets without being logged in and now can’t read too many when logged in. It’s crumbling.

Reddit and Twitter were very centralized locations for information sharing. I hope people invest more in info sites and blogs again.

ftg,
@ftg@mastodon.radio avatar

@EposVox
Tbh can't post or like while logged in for me either.
So there's that.

ftg, to random
@ftg@mastodon.radio avatar

So let's go thru the whole TX chain in this thing.

The upper left corner here as the 1st LO and 1st IF (140MHz) enter that module with teflon PCB holding a Mini-Circuits SRA-1 mixer, those are still made.
But so decadent, low loss PTFE substrate, for a 500MHz mixer!

The microstrip between it and the IF amplifier is a ~360MHz microstrip filter.
Once again decadently on PTFE.
Might be worth it to go to town with a boxcutter on it and see if it pushes up to 70cm or 405MHz weather balloon band.

ftg,
@ftg@mastodon.radio avatar

Here we can se the first four amplifier stages in this transmit converter.
First two white mystery GaAsfets, then "501" feeding a "HP 502".
This then goes to the first isolator.
If you zoom in, you get to see that the amplfiers are actually separate modules with ptfe on aluminum.
And hand tuned with "snowflakes". Hell, the "HP 502" one has handwritten marking in normal pencil.

ftg,
@ftg@mastodon.radio avatar

@f4grx
Yep!
And it gets EVEN better.
Because they can be individually tuned.
There are THREADED HOLES at the edges for mounting SMA connectors.
No drilling required.
Just two screws per SMA.

ftg,
@ftg@mastodon.radio avatar

@recursive
Yep.

ftg,
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@recursive @f4grx
Eighties, so almost 40 at this point.

ftg, to random
@ftg@mastodon.radio avatar

Here's the overall top view of this opened transmit converter module.
It's double conversion.
First IF is 140MHz (suspiciously convenient)
Second IF is 360MHz.
And then it is mixed to Somewhere above 2GHz.

ftg,
@ftg@mastodon.radio avatar

@yuki2501
Copper balance, so that the board etches well.
Not really a concern with modern (eg. not +40years old) PCB processes we have today.

gsuberland, to random
@gsuberland@chaos.social avatar

I seem to remember that there's a 74xx or 4xxx series IC that's like a counter but it just turns one output pin on at a time, like it's counting 1, 2, 4, 8, 16, ... so all you need is a clock line (and optionally a reset) to drive it.

Anyone know the part number?

ftg,
@ftg@mastodon.radio avatar

@gsuberland
Like 4017 or something else?
I don't get the binary sequence, how could that be represented by a single pin?
Or one pin per 1, 2, 4, 8, 16, and in between counting up to the next pin none or the previous one are pulled high?

These days it might be a job for some 17cent SOIC14 or SSOP20 MCU like PY32F002.

ftg,
@ftg@mastodon.radio avatar

@gsuberland
Like 4017, except the pins toggle as as a square of the amount of counts.
I do wonder if some suitable shift register chip could be abused to do that.
I wonder if Rue would know. He seems to specialize in weird stuff and teaching old things new tricks.

ftg,
@ftg@mastodon.radio avatar

@gsuberland
Ah. Nice that my vague memory of those helped!

In junior high some of the shop class electronics projects used 4017+555 to make an electronic "roulette" machine.
Or the one with 7-segment output for a "digital" dice.

Tried to use 3x of those 7-segment one's in cascade to make a counter, but had not yet learned what debouncing was so the salvaged switch made it increment too much per button press and I thought the concept did not work. :DDD

niconiconi, to random

Q: What do electronics engineers do when they are asked to reproduce a software bug that crashes the system only after 100 days?

A: Placing it in an oven, heating it up to 125 degrees, and extrapolate the results according to the Arrhenius equation.

ftg,
@ftg@mastodon.radio avatar

@niconiconi
What is the point where junction temperature does not really matter?
95°C?

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