Project TouCans Antenna Feed Redesign

Halibut Electronics is working on a new satellite antenna kit!

This is kinda cool for two reasons, first because we've recently started attending the high altitude balloon meetups at Noisebridge. Satellite antennas came up during one of the meetings.

More tactically importanly though, the EggNogs docs inspired what be a better tuna can feedtrough for Projct TouCan's antenna! For notes, here's my original EggNogs documentation review reply:

The documentation looks great so far! I've made it to page 17/22. One thing:

For those of us with partners heavily into fountain pens, those of us who like to print out manuals on JIS B5 paper and then store them in Kokuyo Campus binders, page numbers in the table of contents would be very cool. (I know, I know, such a niche group :) )

Mostly though, I wanted to thank you for jogging my memory into a, (I hope), better solution for Project TouCans antenna ports. At present, they're inverted bananna plug posts. Banana plug screw terminals are tiny, and therefore somewhat problematic in outdoor environments. Here's an idea of how tiny

Suspending a two pound rig 6 meters up, eventually the screw threads begin to strip. We stuck with banana plugs though because the insulator around the conductor makes them perfect for mounting in a tuna fish can. Yes, I've read about how Yagis and dipoles are balanced and therefore have 0 volts across the antenna center, so theoretically you don't need insulators, but TouCans frequently hangs at angles to the ground and/or very close to the ground, so, insulators.

Anyhow! The last figure on page 17, the one with the cool weather-proof washer, reminded me that gromets exist! With the correct sized gromet, we can put any size bolt pointing upward as an antenna connector.

And, even better still, we can source them from our local hardware store at the bottom of the hill!

Thanks Mark!
72 de KD0FNR Hamilton

Comments

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...

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 ...

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:...

Copasetic Flow

Search This Blog