ftg

DJDarren, 15 days 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.

azonenberg, 21 days 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.

ftg, 22 days 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

ftg, 22 days 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.

DM_Ronin, 29 days ago to embedded

some hardware chips memes

#Embedded #Hardware

karotte, 29 days 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.

gsuberland, 1 month ago to random

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

ftg, 1 month 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, 2 months ago to random

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

astrid, 2 months ago to random

L + standing wave ratio + f + C + V + P + Z

azonenberg, 2 months ago to random

Is there such a thing as a cost optimized "discharge-only" RF terminator?

Basically, something that you use for discharging ESD from cables and is built to tight mechanical tolerances on the mating interface so as to not risk damage to expensive connectors, but need not be optimized for good return loss out to mm-wave frequencies etc.

@g4dbn @ftg @dlharmon

ftg, 3 months ago to random

Old cellphones were more fun.

I have converted a bunch of these to 70cm .

Btw, Nokia used to sell these things with their Actionet branded MTP1327 network.
IIRC Altai2 is one user of it's derivates, with Nokia RD72 terminals. I guess the units meant for the Chinese market could be used on the old Altai frequencies as well.

astrid, 3 months ago to random

THESIS: computers are a liberatory force, a means for individuals to create art, improve their lives, and communicate

ANTITHESIS: computers are the tool of the authoritarian, and create alienation and systematic oppression

SYNTHESIS: you use da good computer to blow up da bad computer >:3

hacks4pancakes, 3 months ago to random

IDK y’all but my ten year old Honda batteries seem to be rocking it right now in Chicago. Seems like a them problem.

ftg, 4 months ago to hamradio

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

#testequipment #surplus #hamradio

gsuberland, 4 months ago to random

lusting after the Hakko FX-972 but by the time I add the handles and tips it's like £1300 >_<

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.