Jamming jagged lines

June 17, 2009

Picture 4

Over at True/Slant Marc Herman breaks down some of the techniques involved in large-scale signal-blocking, as is the case all over Iran right now. “Jamming” is just one of them; the number of communications channels available today ensures that any entity attempting to abort unsanctioned communications has to throw the kitchen sink at the variegated sources. This piece is a good primer to often overlooked nuts + bolts comm basics for our amped age. It also makes me wonder to what extent these transmittal/reception disruptions are spilling over national borders, as Marc mentions.

As a brief and unrelated aside, how long have electronic signals been depictedfranklin_experiment2 as jagged lines, as in the illo in the T/S post (from a training manual resource)? Did the very first broadcasting proposals employ this imaging of the invisible? Did the graphic serration derive from invisible but measurable waves, such as sound? Or could they have tapped an older graphic convention: the visualization of lightning. From late 17th-century meteorological tracts (bottom image in the link) to depictions of Ben Franklin’s electricity experiments, the jagged line has long been the trope. And of course older yet (petroglyphs don’t count, everything is up for interpretive grabs), but how far back?



  1. Wild guess: in old schematics, didn’t a straight line indicate a fixed connection, and a crosscut line a signal? Or am I remembering that wrong? Here’s a diagram of straight lines:

  2. I had to refresh my memory on this (from childhood electronics kits) but in wiring schema I thought a straight line was a hard connection and a jagged one a resistor: http://en.wikipedia.org/wiki/Circuit_diagram#Symbols
    But it bears further research into early telegprahy patents and more…

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