ftg

azonenberg, 1 month ago to random

New thread on my big ongoing embedded project since the other one was getting too big.

To recap, this is a pilot project for a bunch of my future open hardware T&M and networking projects, validating a common platform that a lot of the future stuff is going to run on.

The primary problem it's trying to address is that I have a lot of instrumentation with trigger in/out ports, sometimes at different voltage levels, and I don't always have the same instrument sourcing the trigger every time.

So rather than moving around cables all the time and adding splitters, attenuators, amplifiers, etc. to the trigger signals I decided to make a dedicated device using an old XC7K70T-2FBG484 I had lying around.

Of course, as with any project, there was feature creep.

I'm standardizing on +48V DC for powering all of my future projects as it's high enough to move a lot of power but low enough to be mostly safe to work around live. So I needed to design and validate an intermediate bus converter to bring the 48 down to something like 12 for the rest of the system to use.

The FPGA has four 10G transceiver pairs on it. I used one for 10GbE (not that I need the bandwidth, but I was low on RJ45 ports on this bench and had some free SFP drops) and the rest are hooked up to front panel SMA ports (awaiting cables to go from PCB to panel) to generate PRBSes for instrument deskew.

Since I'm pinning out the transceivers and am planning to build a BERT eventually, I added BERT functionality to the firmware as well (still need to finish a few things but it's mostly usable now).

And since I have transceivers and access to all of the scope triggers, it would be dumb not to build a CDR trigger mode as well. That's in progress.

DJDarren, 1 month ago to random

It’s just been pointed out to me that the reason Apple runs a trade-in programme for older devices is so they can reduce the size of the used market, and has fuck all to do with recycling.

That’s blown my tiny mind.

DM_Ronin, 1 month ago to embedded

some hardware chips memes

#Embedded #Hardware

ftg, 11 months ago to random

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.

azonenberg, 16 days ago to random

New toy just showed up in the mail... It's my beta ThunderScope!

Will start playing with it after work but here's some quick unboxing pics.

Black Pelican case labeled "ThunderScope" with "made in Canada" "OSHW", and "EEVengers" logos on it
Black instrument case in foam cutout with four BNCs on one side and two on the other, labeled "ThunderScope Beta 2"

karotte, 1 month ago to random

It's more or less widely known that especially high-capacitance ceramic capacitors have significantly less capacitance at their rated voltage than at 0V. While this effect is detrimental for bypass applications, has anyone ever turned that effect into something useful?

I was thinking of using this effect to make a variable capacitor for a VCO or maybe getting some use out of the non-exponential RC charge characteristic.

ftg, 10 months ago to random

My 2.4GHz downconverter runs UNIX.

#surplus #13cm #soekris #hax #2400MHz

ftg, 2 months ago to random

What uses would there be for 7638MHz and 7554MHz DRO oscillators?
Not phase locked, so not super stable, don't multiply immediately to any interesting bands either, so not that usable as a marker either.
And these have a negative supply voltage.

#hamr #surplus #GHz #Xband

ftg, 8 months ago to random

Unhappy spectrum analyzer.

ftg, 7 months ago to random

Is the output port supposed to be bent like that?

ftg, 11 months ago to random

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, 6 months ago to random

Heh, somebody did not look where they pointed the hot air at.

ftg, 11 months ago to random

Who would be some interesting technical folks to add to my follows?
Interested in ham radio homebrew, microwaves, RF, high speed digital, electronics in general and stuff like folks building their own linux SBC's.

ftg, 4 months ago to random

Inside a modern day cheap Ku-band LNB.
Not much where to reduce costs in these at this point.
Absolute bare minimum of parts.

gsuberland, 1 month ago to random

revision schedule 2h behind, gonna need some better living through chemistry to get through this last block

ftg, 6 months ago to random

The only properly re-usable thing on this robot vacuum mother board.

An STM32F103VET6 in TQFP.

ftg, 8 months ago to random

Old telecom stuff sure has a special look.

ftg, 4 months ago to hamradio

Got myself some "new" testgear.
A classic Palomar #noisebridge

#testequipment #surplus #hamradio

ftg, 10 months ago to random

The controller PCB from an Amazfit model A1702 smart watch.
Did this #teardown 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, 5 months ago to repair

Hello lazy web, a friend of mine fudged the NVRAM battery replacement in his Tektronix TDS644B.
One of those Dallas jobbies where you get to really tear into them to pry out the existing batteries.

So now the calibration is gone and the instrument is unhappy.
So what next? Finding some random calibration file and use that and hope for the best?
Maybe some of you know more.

#Tektronix #repair #calibration #TDS644 #TDS644B

ftg, 2 months ago to random

The current POCSAG revival with all the projects and #DAPNET is very nice.

ftg, 10 months ago to random

Just about the only thing a #XML handbook is good for.

ftg, 1 month ago to random

At least, the rack is accessible and more in order.

To be done:

• Power
• Antennas
• Internet for linking the 70cm analog repeater.

The Sepura in the box is an SRG3900 #TETRA radio programmed to our 70cm TMO base station, which is connected to the #tetrapack network.
The idea is to offer better indoor coverage with the TMO-DMO gateway.

The Nokia RD58 based analog 70cm repeater is planed to return to service as an experimental internet linked club repeater on R.Net2.

ftg, 1 month ago to hamradio

Completely reverse engineered datapacket for Quansheng UV-K5 radio.

Not just schematics, but a complete kicad project, so that one can properly document modifications and make derivates.

https://github.com/mentalDetector/Quansheng_UV-K5_PCB_R51-V1.4_PCB_Reversing_Rev._0.9

#hamradio #reverseengineering #quansheng #uvk5 #homebrew