I'm a huge fan of the base16 color schemes - not for their appearance (though most look great), but for their ease of integration within the shell and vim. Just clone the repos below, drop a few lines in your shellrc/vimrc, then use a single bash command to change the scheme in both. No more mucking with Xresources.
Thanks for this! I knew about 256-color and truecolor modes, but I didn't know about the palette-changing escape sequences. I prefer to use the standard 16 colours for portability, but tweak them where possible for comfort. Now I can do that in a shell script instead of messing with the terminal palette on every computer!
Not gonna use those clunky base16 scripts, though. TL;DR in GNU screen:
$ echo -e '\eP\e]4;0;rgb:01/3f/13\a\e\\'
You're absolutely correct about RF noise. In the US, the FCC limits the power of all spurious emissions to be at least 43dB below the power of the fundamental frequency. Typically transmitters use a low pass filter (e.g. Buttersworth or Chebyshev) to reduce harmonic content.
Some micro transmitters (at the very low mW level) omit the LPF entirely. Looking at the datasheet for the ATtiny85, the maximum output current is 40mA and maximum output voltage is 5.5v which means this transmitter could theoretically produce an output of 220mW. PWM will reduce this obviously. The harmonics should be below this value, but they should probably add a filter. I've transmitting across the Atlantic Ocean at those power levels using a sub-optimal antenna and WSPR (https://en.wikipedia.org/wiki/WSPR_(amateur_radio_software)) encoding.
If you cut back the antenna length so you can’t hear the fundamental 100 ft away, the harmonics shouldn’t be an issue. But, I’d have to build it to be sure. I might do that!
Here’s some info on suitable low pass filters for $5. You’d have to modify the 600 meter kit for 555 kHz, after reading up on the design at the linked technical pages.
Note that, for a given too-short antenna length, it will be better at emitting harmonics than the fundamental.
E.g. a 1m antenna is far below resonant for 1MHz AM, but may be pretty good at emitting any 37, 39, 41MHz ... content.
Of course, we expect that content to have less than 1/40th, of the fundamental, both because of Fourier series expansion of a square wave and because the frequency response of the system rolls off (edges off an ATmega aren't perfect, even before you get the reactance of the breadboard in the way.
A primary reason to add a filter, IMO, is to raise the voltage of the fundamental at the antenna, and therefore get a little more RF out on our desired frequencies.
The thing is, ... anyone who's playing with microcontrollers and longish wires is making similar RF noise.
Efficiency of, and coupling to, this antenna is going to be garbage, even for harmonics. And the breadboard itself provides a fair bit of attenuation of the already-small 10MHz-and-up content.
> the maximum output current is 40mA and maximum output voltage is 5.5v
Looking at the maximum power you're supposed to draw from a pin isn't useful. The output transistors can provide much more: it's just not good for the part.
It'd be better to consider the radiation resistance of the wire and the AC voltage driving it.
You can also use the Free Internet Chess Server (FICS) as a test bed for chess engines. The interface is telnet-based, so it's pretty easy to experiment with and learn. There's also "zippy" mode in xboard that allows you to connect your engine to FICS .
The commands below will login as a guest and display all of the computer accounts. Use the finger command to find info about an account.
telnet freechess.org
g <ENTER>
who C<ENTER>
finger ACCOUNT
Sadly, FICS has been dying a slow death for the past 10 years ... but there are plenty of idle CPU accounts waiting for an opponent.
Maybe it has to do with the start of solar cycle 25? Expect to see improving HF propagation over the next 3-5 years. It's an exciting time for radio nerds.
If you have one of the popular RTL-SDR's you may be able to pick up the HF bands by enabling the direct sampling mode (allows tuning between 500kHz - 28.8MHz).
I ran into two problems when trying to switch to a Raspberry Pi 4 8GB as a desktop replacement in mid-2020:
- A noticeably laggy screen update when running urxvt. Any action which caused large amounts of text to scroll on the screen (e.g. a file listing or paging through a man page) would cause a bit of a visual stutter. I was running with with XFT fonts enabled, so maybe that was a contributing factor. Web page scrolling also seemed to lag a bit too if I recall correctly.
- Lack of gamma support for blue light filters such as redshift or f.lux
I'm crossing my fingers there are improvements to these areas in the future.
hyperlinks-- programs can emit an escape code that would be interpreted as hyperlink. so you can do `ls --hyperlink=auto` (yes, it's so useful that a coreutils util has included it) and click on the hyperlink to open the file using xdg-open.
