Archive for September, 2008

links for 2008-09-24

September 25, 2008
  • "This switch and the Selectivity/Frequency controls
    adjust the response of the main filter (all but the Aux
    Notch). PEAK (band-pass) passes a narrow band of
    frequencies, and rejects others — just the opposite of
    NOTCH. LOWPASS passes low frequencies, while
    rejecting high frequencies (e.g. hiss). HIGHPASS is
    the opposite of LOWPASS: it passes high frequencies,
    while rejecting low frequencies. An exception occurs
    at high selectivity, where LOWPASS and HIGHPASS
    take on some of the characteristics of PEAK."
  • "An acoustic high-pass filter may be constructed simply by inserting a "T" junction, or a short side branch into the duct. If both the radius and the length of the side branch are smaller than a wavelengths of the plane waves in the duct then the acoustic impedance of the side branch opening becomes "

links for 2008-09-24

September 24, 2008
  • "For QRP Amateur Radio use. This passive CW filter (PCWF) goes between your HF receiver and an 8-ohm speaker or headphones. Features an 750 Hz center-frequency, 500 Hz LC band-pass design, utilizing three high-permeability cores. Parts assemble on PCB; no batteries are required; and assembly time is about 30 minutes. No battery Maw! Cat# XS-PCWFK $19.95"
  • "In a recent QST, a New Product announcement described a passive bandpass CW filter from the Xtal Set Society (don't be fooled by the name). What caught my eye was the fact the filter could be configured for SSB (as shown in the left photo). A quick look on their web site confirmed this, and that it was designed by Phil Anderson, WØXI, of Kantronics fame. It cost all of $19.95 plus shipping. It took two days to reach me via priority mail."

links for 2008-09-22

September 23, 2008
  • "Weekend Edition Saturday, September 13, 2008 · YouTube has spawned many sudden sensations. Take scraper bikes, for example. A music video about the tricked-out bicycles posted to the site by some teenagers in Oakland, Calif., has attracted a cult following, with nearly 3 million views.

    The video spawned what is becoming a worldwide movement, even as it changed the lives of the young men who customized the bikes and made the video.

    "Actually, scraper bikes saved my life," says Tyrone Stevenson Jr., who prefers the title "Scraper Bike King." "

links for 2008-09-21

September 22, 2008

links for 2008-09-19

September 20, 2008

links for 2008-09-18

September 19, 2008

links for 2008-09-14

September 15, 2008

links for 2008-09-13

September 14, 2008
  • "listen to and control a short-wave receiver located at the amateur radio club ETGD at the University of Twente. In contrast to other web-controlled receivers, this receiver can be tuned by multiple users simultaneously, thanks to the use of Software-Defined Radio. For more information, click here.

    Note that the setup is rather experimental, and neither continuous service nor good performance are guaranteed. "

    "reduced from 16 bits per sample to 8 bits per sample, using the so-called A-law compression, "

links for 2008-09-13

September 13, 2008

links for 2008-09-11

September 12, 2008