Maybe I'm wrong, but my guess is that most engineers and technicians under 35 years old cannot readily interpret numerical color codes. With the advent and subsequent ubiquity of laser-marked numerical codes on both surface mount and low-watt leaded resistors, capacitors, and inductors, the old mnemonic I learned in my high school electrical vocational classes back in the 1970s (which is way too politically incorrect to print here) is passé. In an attempt to encourage a color code renaissance, I have added RF Cafe's color-coded, 10-digit phone number in the footer of these pages. A lot of people use a graphic image of their phone number and/or e-mail on web pages to thwart web bots that are data mining contact information when it is in text form. E-mail your mnemonics and/or suggestions for new usage and I will create a page for them.Surface Mount Technology for PC Boards,
by Hollomon & Blackwell

The July/August edition of Discover magazine has a story about the SETI Institute's history of placing calls to and hoping to answer calls from extrasolar inhabitants. This is SETI's 50-year anniversary. In April 1960, astronomer Frank Drake first began listening for intelligent radio signals from the star Tau Ceti, in the constellation of Cetus, the whale. Drake and Carl Sagan famously sent a message from Arecibo in 1974, pointed at the Messier 13 globular cluster. The above photo is a shot of a control room patchboard at SETI for selecting Butterworth or Gaussian filters of various center frequencies and bandwidths. It appears from the amount of wear on the Gaussian channels that they get the most use. Seeing as how no discernable message has been received to date, maybe it's time to install a panel of Chebyshev or raised cosine filters.

The proprietor of the Excel Hero website contacted me because of a recent addition to his large collection of unbelievably clever Excel spreadsheets. If you appreciate the power of VBA (Visual Basic for Application - I use it in the RF Cascade Workbook series), then you have to spend some time on the site. This particular spreadsheet is for a Smith Chart that is created dynamically from textbook equations. There is a very nice tutorial included. It does not have the built-in ability to plot actual impedance or admittance points, but if you want to do so, you can take a look at the equations I created in my Smith Chart for Excel file (free) and integrate them into this one.Each month, the winner can choose from a list of engineering books. Art J. was the July winner. Click on icon for details.
** 42 winners to date **"'Photo' wants it thick, but 'voltaic' wants it thin." – Michael J. Naughton re efficiency of photo cellsIEEE TV has a video reporting on a 270 MW geothermal power generation facility on the grounds of the Naval Air Weapons Station in China Lake, CA. The underground heat generated by the friction of tectonic plates in relative motion manifests itself on the surface with hot springs and bubbling mud pits. It is the perfect opportunity for tapping energy. Per the narrator, enough electricity is generated to not only power the facility, but also to sell power back to the grid. It is one of the largest of such facilities in the U.S. Unlike wind turbines and massive solar cell arrays, geothermal and hydro generation are are very efficient, low maintenance, are and non-polluting.

If you are kind enough to consider providing a reciprocal link from your website to RF Cafe, then here are a few pre-prepared formats that you might consider.