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ULF/ELF/VLF receiver and antenna (2007.10.09:2 tech_notes2#20 maxwell_notes#9)



receiving ELF waves in a frequency range between zero and approximately 25 Hz

various VLF receivers/EM sniffers:

Installing Rohan Drape's rsc3 Scheme Supercollider: (tech_notes2#19)

1] Installation:

apt-get install mzscheme

darcs get http://www.slavepianos.org/rd/sw/rsc3/

cd rsc3; setup-plt; make; cd ..

cp -R rsc3 /usr/lib/plt/collects

2] in .emacs:

(add-to-list 'load-path "/root/rsc3/emacs")
(require 'rsc3)
3] in .rsc3.scm

(require (lib "rsc3.ss" "rsc3")
         (only (lib "process.ss") system))

(define s (open-udp* "" 57110))

(define (boot*)
    (putenv "SC_PLUGIN_PATH"
      (putenv "SC_SYNTHDEF_PATH"
        (system "scsynth -u 57110 &")
          (sleep 0.5)
            (reset s))

(define (draw* g)
    (draw g "/tmp" "dotty"))

4] M-x rsc3-boot-scsynth

5] Testing:

;; (DiskIn numChannels rate bufnum)

;; Continously play a soundfile from disk. This requires a buffer to
;; be preloaded with one buffer size of sound.  The buffer size must
;; be a multiple of twice the synth block size. The default block size
;; is 64.

;; Note that DiskIn reads the number of outputs to create from what
;; looks like an input, but it is not an input, and cannot be set
;; using a control.

(let ((f "/root/testantenna.wav")
      (n 1))
  (->< s (/b_alloc 0 8192 n))
  (->< s (/b_read 0 f 0 -1 0 1))
  (play s (DiskIn n ar 0)))

(reset s)

(begin (->< s (/b_close 0))
       (->< s (/b_free 0)))

 (define analog-bubbles
      (let* ((a (MulAdd (LFSaw kr (Mce 8 7.23) 0) 3 80))
                       (b (MulAdd (LFSaw kr 0.4 0) 24 a)))
             (CombN (Mul (SinOsc ar (MIDICPS b) 0) 0.1) 0.2
                    0.2 4)))

 (play s analog-bubbles)
after: http://www.cs.brown.edu/pipermail/plt-scheme/2007-January/015947.html