cybergibbons

@cybergibbons@infosec.exchange

That fucking cyclist from Twitter.

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cybergibbons, to random

Built a tiny valve pre-amp with the Bean today.

Works surprisingly well. Seems to have a gain of around 5.3 and works from 40Hz up to 300kHz - way beyond audio.

image/png

cybergibbons, to random

Someone going full AM in the middle of the amateur band.

Carrier keeps on showing up now but with no audio.

cybergibbons, to random

In the audio world, is there a secret code or way of telling if a 1/4" TRS socket is balanced mono or unbalanced stereo?

Is there a standardised way to convert between them?

cybergibbons,

@gsuberland it's super strange how there's not a clear icon or form.

cybergibbons,

@gsuberland I kind of get it in professional settings. But on domestic/home stuff - an icon showing which it is would make a lot of sense.

cybergibbons, to random

Just had a look into some EV charging issues someone is having.

EVSE was installed just before Christmas.

Had a quick look but it was raining heavily. It's a good distance - at least 30m as the crow flies - from the house.

It's on 2.5mm^2 T&E. It seems to allow 32A charging. Already alarm bells.

The owner also complained about lights dimming in the house...

So I measured the voltage under base load in the house. 205V.

Turn the hobs and oven on, and we're <200V.

Plugged in a light 50W ish load into the EVSE (janky EVSE simulator), and it's down at 195V. I can see that getting into the 180V region.

Super dodgy.

cybergibbons, to random

I thought I'd take a look at what my headphone DAC did when you turned "Bass" on and off.

It's actually quite a jump - around 6db!

cybergibbons,

The THD is actually quite high on the headphone DAC. Noise floor is a little higher but not bad.

Green is measuring equipment in loopback and blue is the headphone DAC.

image/png

cybergibbons,

@gsuberland so the DAC is USB powered - so I reckon there is a boost converter switching at 18kHz?

cybergibbons,

@gsuberland the guts...

cybergibbons,

@gsuberland I'll open it another time and probe about.

cybergibbons, to random

Well that's me not buying cheap wire anymore

cybergibbons, to random

I remember the days when measuring the noise of every device around me wasn't a thing...

cybergibbons,

This is really quite impressive - the noise floor is less than 1uV. Really around 500nV.

THD of -102dB on this 1kHz source is good.

cybergibbons, to random

Question in a school text book:

"A 10 volt battery loses 1% of its capacity every time it is recharged. How many times can it be recharged before its capacity falls to below 1 volt?"

U wot m8?

Do you even battery, bro?

cybergibbons,

@simonzerafa even then, it's terrible.

Loses 1% of which capacity each recharge? The full discharge capacity, or the degraded one?

gsuberland, to random
@gsuberland@chaos.social avatar

one of the best decisions I ever made in life, as someone who is a security professional who also tinkers in many other fields, was the conscious choice that every web app side project must be fully unauthenticated or single user with the authentication delegated entirely to the httpd.

none of the data these apps handle is particularly important and the design complexity skyrockets as soon as you start to think about authentication and user privileges.

cybergibbons,

@gsuberland I have seen a lot of decent projects and products just curl up and die because they've had to add too much stuff.

A good example are some ICS devices - they have telnet and an enable password.

Someone adds a web interface. Now we have permissions. And user levels. And sessions. Some little shit like me tests it and finds loads of issues in the web interface.

cybergibbons, to random

It's crazy how China Radio International broadcasts on shortwave 24/7/365 in about 44 languages.

And that many of these are loud and clear in the UK.

cybergibbons,

@gsuberland I was just about to look into that!

cybergibbons, to random

It's interesting how distinct some audio is when transmitter by FM radio.

These are stringed instruments.

cybergibbons, to random

I've done electronics since I was 8. I've got a masters in electronic engineering. My day job is 20% electronics. Many of my hobbies are electronics.

Can I remember the resistor colour code?

No.

cybergibbons,

I mean, maybe more to the point, do I need to?

Most of my work, the only resistances I care about are "short", "probably a current shunt", "probably for an LED" and "pull-up/down"

hacks4pancakes, to random

Everyone keeps sending me that news article about the German railway trying to hire a DOS and Windows 3.1 expert. You don’t understand- that is my whole job. That’s literally my normal day to day cybersecurity career.

cybergibbons,

@JessTheUnstill @hacks4pancakes one of the ICMS systems for mid-sized ships has ended up with the situation that the vendor reconditions and stockpiles old machines rather than just update the software!

It's utter madness. They've even made some janky adapter so they can use SSDs with some 1980s era inteface like MFM.

cybergibbons,

@JessTheUnstill @hacks4pancakes I think there are a few people who do stuff in this space, though oddly it's mostly for retrocomputing rather than industrial/scientific.

Never underestimate the power of someone wanting to relive their childhood!

cybergibbons,

@jernej__s @Polypompholyx @hacks4pancakes I think you can still pay for some degree of assistance as well, say if you are trying to migrate onto something newer.

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