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The 20.1 MHz radio receiver kit we ordered from Radio Jove arrived last week.  Lots of tiny components to solder onto the PC board.  I seem to have forgotten the color code for resistors. 

The kit comes with conductors and fittings for a dual dipole antenna. I’ll have to go to Home Depot and buy parts for the support structure.  The antenna is going to take a bit of real estate to set up.  Given that Jupiter is low in the sky for a few years, it is desirable to contrive a means for narrowing the antenna beam to help with some noise rejection.  A properly configured dual dipole 15 or 20 ft off the ground helps a bit. 

A powerful station already broadcasts at 20 MHz (WWV), out of Ft. Collins, CO, so the receiver is offset at 20.1 MHz.  Jupiters cyclotron radio emissions are strongest between 18 and 24 MHz.  For locations distant from Ft. Collins, the broadcast at 20 MHz may be irrelevent. The ionosphere is mostly transparent to 20 MHz radiation on the night side of the earth, so transmissions from interfering sources in this band tend to propagate into space at night rather than reflect off the ionosphere and go beyond the horizon.

Th’ Gaussling has been busy studying the basics of antenna theory.  It’s quite interesting, really.  An antenna is basically a transducer, converting energy from one form into another.  The knowledge of antennae is something of a dark art.  I have had to scrounge to find resources that explain without too much forgotten calculus. 

Once you have antennae on your brain, you begin to notice them everywhere. All sorts of them. Yagi’s, dipoles, dishes, mast antennas, and folded dipoles jutting off of every imaginable high spot. I have one bolted to my house. 

The side benefit for yours truly is that it has forced me to have a hard rethink about electromagnetic radiation and the mechanism for its generation. We organikkers generally don’t spend a lot of time thinking about radiation emission and propagation. 

There could be some pedagogical advantages to introducing students to electromagnetic radiation in the radio spectrum rather than the visible range. The acceleration of charges in an antenna element and the subsequent perturbation in the charge field around the charged particle seems to be conceptually easier to reach than the usual abstractions showing the 3-D rendering of a sinusoidal wave in most textbooks. In fact, I have never seen a good representation of visible photon emission beyond arrow pushing on an energy diagram.   Who knows, maybe a student would learn something about electricity as well?

Hey. Check out the Quantum Slacks by Haggar.  The first of their Non-Newtonian line.


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