TIL: Atlatl Antenna Launch

I learned about atlatls and their application to ham radio today.

First, they're not to be confused with Axolotl, one of the Characters from catscafe:

An atlatl is a spear thrower according to Wikipedia. I vaguely remembered them from third through fifth grade social studies classes in Hobbs, NM, and Anthropology 101 at Ohio State. The reason I rememberd them is becuase of the degree of difficulty in stringing a half-wave diople on Mt. Davidson, W6/NC-423. There's a pair of trees that look awesomre for just such an installation on 10 meters, but the branch of one of them is tantilizingly just out of reach when throwing a spool of butchers twine by hand.

The tree in question:

So, it usually takes upward of half an hour just to get the antenna and radio launched. But! Today, I figured out the answer, and it's—get ready for it—an atlatl.

Placing the spool of twine on the end of a stick, and then throwing it resulted in the antenna line being ready to go on the first throw... two branches higher up than ever before!!!

It's important to mount the spool with the string facing the direction it will leave the end of the stick. If the string trails the spool, there's a pretty high chance it will wrap itselff aroudn the stick.

There's a ton more to say about all this after readhing the atlatl article I referenced above, at least physics-wise, but anyway...

Comments

More Cowbell! Record Production using Google Forms and Charts

First, the what : This article shows how to embed a new Google Form into any web page. To demonstrate ths, a chart and form that allow blog readers to control the recording levels of each instrument in Blue Oyster Cult's "(Don't Fear) The Reaper" is used. HTML code from the Google version of the form included on this page is shown and the parts that need to be modified are highlighted. Next, the why : Google recently released an e-mail form feature that allows users of Google Documents to create an e-mail a form that automatically places each user's input into an associated spreadsheet. As it turns out, with a little bit of work, the forms that are created by Google Docs can be embedded into any web page. Now, The Goods: Click on the instrument you want turned up, click the submit button and then refresh the page. Through the magic of Google Forms as soon as you click on submit and refresh this web page, the data chart will update immediately. Turn up the:

Cool Math Tricks: Deriving the Divergence, (Del or Nabla) into New (Cylindrical) Coordinate Systems

Now available as a Kindle ebook for 99 cents ! Get a spiffy ebook, and fund more physics The following is a pretty lengthy procedure, but converting the divergence, (nabla, del) operator between coordinate systems comes up pretty often. While there are tables for converting between common coordinate systems , there seem to be fewer explanations of the procedure for deriving the conversion, so here goes! What do we actually want? To convert the Cartesian nabla to the nabla for another coordinate system, say… cylindrical coordinates. What we’ll need: 1. The Cartesian Nabla: 2. A set of equations relating the Cartesian coordinates to cylindrical coordinates: 3. A set of equations relating the Cartesian basis vectors to the basis vectors of the new coordinate system: How to do it: Use the chain rule for differentiation to convert the derivatives with respect to the Cartesian variables to derivatives with respect to the cylindrical variables. The chain

The Valentine's Day Magnetic Monopole

There's an assymetry to the form of the two Maxwell's equations shown in picture 1. While the divergence of the electric field is proportional to the electric charge density at a given point, the divergence of the magnetic field is equal to zero. This is typically explained in the following way. While we know that electrons, the fundamental electric charge carriers exist, evidence seems to indicate that magnetic monopoles, the particles that would carry magnetic 'charge', either don't exist, or, the energies required to create them are so high that they are exceedingly rare. That doesn't stop us from looking for them though! Keeping with the theme of Fairbank[1] and his academic progeny over the semester break, today's post is about the discovery of a magnetic monopole candidate event by one of the Fairbank's graduate students, Blas Cabrera[2]. Cabrera was utilizing a loop type of magnetic monopole detector. Its operation is in concept very sim

Copasetic Flow

Search This Blog