Why Did I choose Engineering?

Because of things like this:

There’s a serious personal reward to projects like that.  I do love how there’s even a trigger mode.

My wife just sat staring in astonishment.  Her dad has a prosthetic from an industrial accident.  While he doesn’t have smart limb, he does have a quite high tech limb that flexes and moves naturally.  Most people don’t even realize he has one unless he’s wearing shorts. 

10 years ago, this type of stuff was still fantasy for the most part.  The amount of processing and input gathering required limited the ability to create something usable.  Moore’s law is a freaking awesome thing.

We Need More Power!

So, we had a unique power source for field day.  A hydrogen fuel cell.


There’s a bank of lead acid deep cycle batteries under the fuel cell.  The cell basically acts as a battery tender charging the batteries and supporting the load while it is on and then turning back off when the batteries are full.


We ran a 48V DC bus (see the extension cord coming out on the left) ran that back into the communications trailer.  This decreased the I2R losses (see also here for info) from the longer cable run.  Within the trailer was a DC to DC converter that put out 13.8V for all of our communications equipment and we also had adapters to run our laptops and other equipment.


It actually was quite effective and we started with an “empty” tank and still ran for over 8 hours on it.  The calculations are we could run for over 48 hours on a single tank of hydrogen.  The cell its self has a rating of 1KW and we actually did get it up that high, however I didn’t get a picture of it.  The fuel cell was running like mad because we left it off after out thunderstorm to let things dry out.

In the mean time we kicked back into operational mode meaning 2 radios fired back up plus their associated computers and associated equipment for digital operation.  All just running off the batteries without the Fuel Cell maintaining them when necessary.

Our clue to go turn the cell back on was when the low battery alarm went off in the trailer indicating the 48V supply was starting to drop.  We did also have a 12V batter on the other side of the 48V to 12V converter in the trailer.  This was to add extra isolation for surging loads (radios).


The fuel cell worked great and was always fun when someone would brag about running off of solar.  Yeah, well we’ve harnessed the power of molecular bonds!

For those who don’t know how fuel cells work, the basic premise is that the electron from hydrogen is forced through the circuit as the proton mates with the oxygen to form water.

Now some would call this a wonderfully green technology, however that hydrogen has to come from somewhere, and most often than not it’s through electrolysis.


*Also as an aside since the wife and I were just talking about it.  If you’re a ham, do not use the term kilo-watt for phonetics.  The word you’re looking for is kilo.  Kilo-watt is very confusing because it is a compound word.  Are you saying K or KW?  Other’s do use the term watt for W, which while incorrect can further add to confusion.  Seriously, the IACO/NATO/ITU phonetic alphabet was developed specifically to limit confusion.  If your word choices were so great, why haven’t they adopted them?

You may think it’s neat and cute, but at least in the case of the wife and I, we slow way down to deal with your choice of phonetics.  I am reasonably sure that I am not the only one who has been confused by this usage.  It’s hard enough to dig phone messages out of the weeds, why add a bit of extra confusion to the conversation.  But that’s just my two cents, take it for what its worth.

Buwahahaha!!! Awesome!

I just discovered this in Jetpack while waiting for my code to compile.

e^{\j \theta}=\cos{\theta}+\j \sin{\theta}

But wait, there’s more!

[\vec{\nabla} \cdot \vec{\mathbf{E}} = \frac{1}{\epsilon_0}\,\rho ]

Man, that is freaking awesome.  I can write formulas on the fly now and not have to resort to weird things to get the images to post.  Now I just need to get back to doing those posts on the power system.