Fasteners, Vibration, and Locknuts

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Compressor Smashing

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How to Mash the Compressor

VLC contains a built-in audio compressor. This can be taken advantage of for spoken word material and for movies, in the case where you need to reduce the dynamic range of the material due to a loud environment, or compress the peaks above a certain point to prevent excessive loudness.

Audio Effects -> Compressor
 - Check Enable
 - RMS / Peak: 0.0
 - Attack: 1.5 ms or as fast as it will go
 - Release: 2 ms or user option as to release time
 - Threshold: -24 dB
 - Ratio: maximum (20:1)
 - Knee: maximum (10:1)
 - Makeup gain: 24 dB

Note that adjusting threshold will put the compressor into action earlier and limit the output amplitude of the compressor; the makeup gain is directly related to this number to flatten out the overall amplitude of the compressor output.

Adjusting the attack and release introduces various effects and depending on time constant, can make aspects of the audio stream "pump". This is not a desired effect. Multiband dynamics processing in radio stations avoids pumping effects in the bass region if at all possible.


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Birdwatcher is a word which has mostly avoided the internet generation entirely. Birdwatcher is an automated telemetry system with two pilot inputs, an A button and and a B button, and the rest of the inputs were specific telemetry inputs on the aircraft. The A-12 had a Birdwatcher system, as well as the CIA version of the U-2. Both of these aircraft or similar variants (U-2S, SR-71) were transferred to the 9th SRW, 4080th, and other related divisions.

Birdwatcher also involved a time-division aspect to the received signal. A physical measuring apparatus is used to determine the source module of the telemetry burst from a strip-chart recorder.

For more information, look to the dead trees.

pdftops filter failed

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If you're reading this, you probably have a problem with Cups and pdftops failing. Install xpdf and some version of libpoppler. This is an unresolved dependency.

Terminal Gibberish

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When your terminal is liberally filled with terminal gibberish, there are a few solutions suggested on stackexchange:

I suggest this:

echo ^V^[c

Alternatively (noobish):

echo <CTRL-V><CTRL-[>c

The actual character being echoed is ^[ followed by the letter c, but to pass control-[. one must type CTRL-V before other CTRL- sequences. Clear as mud, eh?

Thermodynamics or Thermonuclear War

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Law I: You can't win, you can only lose.
Law II: The only way to win is not to play.

In thermodynamics and energy conversion systems, the rules of thermodynamics are immutable. The only variables to implementation are 1) cost of design, 2) labor cost of design implementation, and 3) materials cost of design implementation. These variables all support one equation to calculate a single value: return on investment (ROI), less maintenance cost.

In converting from AC to DC or DC to DC, the fewer the steps, the greater the efficiency. The more transistors act like switches and less like variable resistors, the higher the efficiency. The lower the loss in the transformer or inductor stages, the greater the efficiency. A 90% (0.9) efficient inverter connected in series with another 90% (0.9) efficient inverter results in an overall efficiency of (0.9 x 0.9 = 0.81) 81%. Thus it is most important to make sure that any conversation stage is as efficient as possible to eliminate losses which will invariably appear as heat. This is true of electrical distribution systems, backup power supplies, line-shaft power systems, and belt-powered systems as well.

In a belt-based transmission system, losses can be as high as 5% per stage. Similarly, gear-based transmission systems and hydraulic systems also suffer from losses due to realistic implementation concerns. Multiple stages, lubricants or lack thereof, and turbulence further lower overall efficiency. Thus, while it may be possible to store energy from a solar collector by raising a rail car full of concrete to twice it's height, much energy may be wasted in mechanical gear trains unless a mechanically large gear is used and a small pinion. Even then, one would need a considerable motor/generator to convert from electrical to mechanical.

AT&T Tower Resources

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Free Rigging Guides

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AM Tower Heights by Frequency

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This is a document apparently originating from ERI, Inc, being circulated around the internet on various blogs and sites. AM tower heights listed by frequency for 1/4-wave and 1/2-wave lengths, in feet and meters.

The All-Pass Audio Filter

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The All-Pass Audio Filter is useful for a few reasons:

1) Symmetry of the audio. The human voice is often not symmetrical, and depending on the signaling circuits or transmitter design, it is desirable to limit any sort of inherent DC bias in the transmitted signal. This is an issue for AM and FM transmitters, as well as twisted-pair loops carrying voice communications.

2) Phase correction. The allpass network permits a correction of frequency-dependent phase rotation caused by preceding or following signal processing stages.

In digital signalling networks, these problems are addressed by line coding. The methods of AMI and B8ZS are used in telephony signalling to eliminate a DC bias which would compromise the wire loops and contribute to additional cross-talk coupling, as well as permit the signal to be AC coupled onto a line carrying DC power at -48 VDC or -130 VDC.

Similarly, AX.25 uses Non-return-to-zero inverted (NRZI) to mitigate a similar protocol-based DC bias which would otherwise result from the nature of the data packets. Ethernet relies on 8b/10b encoding in slower forms, and 64b/66b encoding in faster forms to neutralize DC bias as well.