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Concept radio for amateur satellite communication

This Listed platform might also be useful to serve as an idea and project log. In a way, I can pretty much just set some of my personal notes to publish on Listed, with only some minor additional context provided for the reader. So here goes...


You may or may not know that there are satellites orbiting the earth carrying amateur radio equipment, allowing people to make contacts across much larger distances than they normally would be able to. Working these satellites is fun because it is a little challenging, but it can be done with inexpensive and even home-made equipment.

Here's a picture of one being assembled:
The D-Star One amateur radio satellite being assembled by a worker on a lab bench.

Look how small these guys are. And this is, comparatively, a big one.

There are two main types of amateur radio satellites, simple FM repeaters and linear transponders. The FM repeaters are very easy to use and the regular Joe with his inexpensive handheld can make acceptable contacts without much special equipment. The linear transponders require a lot more fiddling and more specialized equipment. This is mostly because the equipment is not available in a handheld form factor.

So I thought, why not? If I can build a radio to make working the linear transponder satellites almost as easy as the FM satellites, well there might be a market there. And it at least seems like it would be an interesting project.

So, I have the education to design an analog circuit to do the job, but it would certainly be a lot of work (likely much of it trial-and-error). But in this day and age where there is a breakout board available for almost everything, it seems like I should be able to string together a pile of circuit boards to do this task. That doesn't seem to be the case for analog. But SDR is the cool thing now, and that's where we might be able to make this work.

Fast forward to a couple days ago after snooping around the internet off and on for a few weeks and I think I've settled on a concept. I've set aside some better but more complicated ideas for the moment and have what I believe to be, essentially, the makings of a minimum viable prototype. (Not yet a minimum viable product.)

As my English teacher used to say, let me amplify.

To receive the signals, the RTL-SDR dongle should be fine, especially with some filtering and preamplification. We can feed that into a Raspberry Pi running some SDR software, with the audio going out to the user via the built-in pins, some sort of "hat," or even a USB sound card. For transmitting, there is a software package called Rpitx that toggles a pin on the Raspberry Pi fast enough to make it a radio transmitter. Run that through some filters and amplifiers and you've got yourself a full-duplex radio ready for satellite operations. I'd want to add a few more bits and pieces like a screen and some buttons and encoders, but we're pretty much good to go with just the handful of components I describe above. (Well, an astute reader might have noticed that I didn't explicitly mention audio in, but you get my drift.)

I suppose my next step is to make a list of the parts to see if this thing can really go together like I want. I see a few issues on the RF input and output side, particularly how I want to multiplex the filtering and amplification since we will be working with two frequencies on two different bands which can either be used as transmit or receive frequencies depending on the satellite.

My email signature is bigger than your email signature

I don't believe I'm the first one to notice this, but the longer the email signature the lower on the totem pole the employee.

To wit: My employer's CEO signs most emails with a single letter.

First Post

So, this is clearly not my actual first post, but I'm starting a new project where I keep the internet informed about my progress toward financial independence and freedom to do with my time what I will. I hope that this project will keep me on track, if at least to not embarrass myself before the entirety of the internet.

Entirety is probably a bit of a stretch. I'm not even sure if more than one person will read this.

None the less, I hope to explore both the whys and the hows of becoming a hashtag vanlife digital nomad or whatever the kids are calling it these days. I'm not actually planning to live the #vanlife, and I have a family that probably doesn't want to live nomadically. Rather, I simply want to spend a little more time with my family and with myself. And I believe a lot of the techniques you see online for digital nomadism can be applied to a more staid life that even a boring nerd like me would want to live.

So if things get rolling, I hope to be able to show others that it can be done and, more importantly, that they can do it themselves.

At Least What You do Means Something

At least what you do means something.

I had someone tell me that, partly to compare themselves to me (in a purposefully unflattering manner for themselves) and partly to make me feel better -- to make me feel more fulfilled and less stressed, trapped, and stagnant.

But it got me thinking.

So, what I do does mean something. I design a significant part of major infrastructure projects that will last for many years. People will be driving over them, safely, on their way to vacations or work or delivering goods for half a century or more. That is objectively cool.

But it's also true that what I actually do every day doesn't matter in the same way. As we gain experience and get more adept at the engineering, learning how to complete our tasks more quickly, the balance of our time gets filled with new tasks. Notably, most of these new tasks do not seem to be centered on our goal of designing a safe, efficient bridge, but rather they facilitate some sort of administrative or leagalistic CYA process.

Now, I don't want to be just another guy complaining about the bureaucracy. That's old and lame and not particularly productive. I get the value of the administrative aspect of our projects because that's how they actually get done without too much graft. That's how they get bid fairly and how we ensure that they get built with the quality materials we designed for. But it just feels like it is getting out of hand (especially when I interview my predecessors who worked, successfully, in a very different world).

I wonder if this administration inflation is actually a thing, almost like a fact of nature. It's as though we make sure to keep each man-hour as complicated as it ever was: Even as we simplify or automate processes, we make sure to add new things to do. And those new things are invariably boring. They are things like generating paperwork, reviewing checklists, reformatting margins, sizing type, and so on.

Is it some failing of our human minds that we can't just enjoy the benefits of progress without burying them in new, extraneous filler? According to Keynes, we were supposed to be working four days a week by now. But as we got more productive, we just did more stuff in the same time (more stuff of, I suspect, marginal utility toward the end goal). I think these are related. And, perhaps optimistically, I think it is a matter of psychology and not nature per se.

Hopefully some day, as a species, we can escape the rat race we built for ourselves. And, in the meantime, perhaps I can free myself and my family while I wait for the rest of us to catch up.

FIGlet Test

I thought it would be cute to use FIGlet for some of my notes. So this is just a test. Let's see how it looks exported to Listed...

      ___                     ___                         ___                 
     /  /\      ___          /  /\                       /  /\          ___   
    /  /:/_    /  /\        /  /:/_                     /  /:/_        /  /\  
   /  /:/ /\  /  /:/       /  /:/ /\    ___     ___    /  /:/ /\      /  /:/  
  /  /:/ /:/ /__/::\      /  /:/_/::\  /__/\   /  /\  /  /:/ /:/_    /  /:/   
 /__/:/ /:/  \__\/\:\__  /__/:/__\/\:\ \  \:\ /  /:/ /__/:/ /:/ /\  /  /::\   
 \  \:\/:/      \  \:\/\ \  \:\ /~~/:/  \  \:\  /:/  \  \:\/:/ /:/ /__/:/\:\  
  \  \::/        \__\::/  \  \:\  /:/    \  \:\/:/    \  \::/ /:/  \__\/  \:\ 
   \  \:\        /__/:/    \  \:\/:/      \  \::/      \  \:\/:/        \  \:\
    \  \:\       \__\/      \  \::/        \__\/        \  \::/          \__\/
     \__\/                   \__\/                       \__\/                
                  ___           ___                 
      ___        /  /\         /  /\          ___   
     /  /\      /  /:/_       /  /:/_        /  /\  
    /  /:/     /  /:/ /\     /  /:/ /\      /  /:/  
   /  /:/     /  /:/ /:/_   /  /:/ /::\    /  /:/   
  /  /::\    /__/:/ /:/ /\ /__/:/ /:/\:\  /  /::\   
 /__/:/\:\   \  \:\/:/ /:/ \  \:\/:/~/:/ /__/:/\:\  
 \__\/  \:\   \  \::/ /:/   \  \::/ /:/  \__\/  \:\ 
      \  \:\   \  \:\/:/     \__\/ /:/        \  \:\
       \__\/    \  \::/        /__/:/          \__\/
                 \__\/         \__\/                

It seems to me to be ideal for a note-taking app that is meant to be text-based.