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mattofak

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UA 1093 9 months ago

The uAvionix EchoESX [1] claims 4W continuous and with antenna probably adds 400g (0.8lb.)

WindBorne claims "12+ days typical flight, with demonstrated capability for 75+ day missions." So 1150Wh minimum (80Ah at 4S, which is probably like 16lb.) But you're up in the atmosphere and probably need to heat that battery so... more. But we're already at 18lb additional weight... Maybe you could offset with solar panels...

But, given that the entire balloon and payload weighs 2.5lb we're already way off the edge of feasibility for an active ads-b out.

Maybe there's something that would only listen and then respond when it heard something and that would reduce the power draw. But we're needing something 2 orders of magnitude less massive.

[1] https://uavionix.com/general-aviation/echoesx/

It's possible it never made it into production; but when I was helping to commission a 4 rack "supercomputer" circa 2010 we used APC's in-row cooling (which did glycol exchange to the outside but still maintains the hot/cold aisle) and I distinctly remember reading a whitepaper about racks with built in water cooling and the problems with pressure loss, dripless connectors, and corrosion. I no longer recall if the direct cooling loop exited the building or just cycled in the rack to an adjacent secondary heat exchanger. (And I don't remember if it was an APC whitepaper or some other integrator.)

There's also all the fun experiments with dunking the whole server into oil, but I'll give you that again I've only seen setups described with secondary cooling loops - probably because of corrosion and wanting to avoid contaminants.

This sounds fun to play with and get feet wet in HDL, but it's only a lattice ice40, I have no idea what you'd seriously do with this. Usually ice40 are used as glue logic, or multiplexing/buffering a bunch of ADC/DAC chips so the processor can do large data transfers instead of a bunch of tiny ones.

The website claims hardware acceleration and... I doubt they got timing closure on the soft CPU at anything greater than 100MHz and you still have to get data to/from it at likely 30~40 MB/s via an SDMMC bus.

Could be struck by a micrometeorite, or if they were doing a station keeping maneuver something could have gone wrong with a thruster. (Apparently the first in it's class Intelsat-29e was lost due to a fuel leak, so maybe there is something systemically wrong in the spacecraft bus.)

I've had to get a medallion before to move a small retirement account and there were two things I very much did not like about the process:

(1) Most institutions require you to have been a member for 6 months before they will grant a medallion. I was transferring money between Fidelity and Schwab. Neither of which have branch offices within an hour of where I live. And I only have a virtual bank. There was no one willing to give me a medallion because I have no local banking relationships. I had to pull a favour with work to get our controller to vouch for me at our business bank.

(2) I've done domestic and international wires for much more money without needing anything like a medallion. Why can't I do something like log in to Fidelity and wire the funds across directly?

(Also, have fun finding the forms required to transfer your retirement account. Fidelity at least made the process exceptionally difficult, and their customer service agents acted like they didn't know what a Simple IRA was or why one would want to transfer out. Sure there's a page about transferring, but it likes to loop you into the "transfer funds into" flow.)

allocortech | Software or Electrical Engineer | Waynesboro, VA | Prefer Local | https://www.allocor.tech/about/work-with-us/

allocortech is a small company (14 people) building control electronics for, typically, unmanned electric aircraft and watercraft. Think motor controllers, battery management systems, and communication hubs. We do both commercial off the shelf sales and custom designs on request; which ultimately means that there is a lot of variety in the month to month projects.

Our vision is to have qualified hardware devices that our customers are free to build their software and vehicles on top of. We provide the initial know-how for robust, redundant, safety critical, and certified software development and have a framework they can leverage if they choose to do so. Ideally this means less re-inventing the wheel for them and more chance of their success.

We're searching for

* A software engineer competent in C and/or C++ with big bonus points for experience in writing device drivers and other low level hardware abstraction layers.

* An electrical engineer to help us do schematic capture and board layout. Bonus points if you've worked with or better: 6+ layer boards, 4/4mil rules, moderate pitch BGA (0.65mm), and have done signal integrity (less than 1GHz) or power domain analysis work.

We're hardware focused and haven't figured out a way to allow 100% remote; but if you come with ideas on how to make it work, we can figure something out. Otherwise we're happy to pay relocation costs and allow 50/50 time splits.

$80~150k full time + options based on experience. We deal with ITAR, so unfortunately US residents, green card holders, asylee or refugees only.

careers@allocor.tech

A small counterpoint; structures made of a weathering steel, like COR-TEN, don't need to be painted. The trade offs include ensuring the welds weather at the same rate as the structure and needing a salt alternative for de-icing in the winter.

The most prominent example I know of is the New River Gorge Bridge in West Virginia.