Archive for month: September, 2009

How to use Python to predict satellite locations…

September 27, 2009 | Amateur Radio, Amateur Satellite | By: Mark VandeWettering

Occasionally I get to talk to hams who are just getting into using amateur satellites, and many of them ask the quite reasonable question “How do I figure out when the next pass occurs?”. For most of them, I suggest that they simply use a program like predict, which is probably what most people expect […]

Gutenberg Gems: Encyclopædia Britannica, Volume VIII slice III – Destructor to Diameter

September 26, 2009 | Gutenberg Gems | By: Mark VandeWettering

It’s been a while since I posted a link to a Gutenberg Gem. I am subscribed to the Project Gutenberg feed, and scan it from time to time. Today’s Gem is volume 8 from the Encyclopædia Britannica: which includes topics from Destructor to Diameter. Interestingly, it includes an entry for “Dialing”, which is also known […]

Today’s weather, courtesy of NOAA 19…

September 26, 2009 | Amateur Radio, Amateur Satellite | By: Mark VandeWettering

Nothing more to say…

WSPR back online, but performance is marginal…

September 26, 2009 | Amateur Radio | By: Mark VandeWettering

My WSPR setup is back online, but my receive performance is marginal. I am not sure, but my wire dipole may have developed a fault or something, I’ll be out there today doing a visual scan, and then maybe hook up my antenna analyzer and see what is the deal.

The Mathemagician and Pied Puzzler, and others | MetaFilter

September 25, 2009 | Math, Puzzles | By: Mark VandeWettering

This metafilter post has a link to several interesting recreational and math puzzle books available as downloads. Very cool. The Mathemagician and Pied Puzzler, and others | MetaFilter.

Recently Launched Cubesat Frequencies

September 24, 2009 | Amateur Satellite | By: Mark VandeWettering

Andrew, VK4TEC posted this list of frequencies for four recently launched cubesats. Archiving for future reference. I’ve added links to some relevent info for each. ITUpsAT1 is on 437.325 MHz CW ITUpSAT1 is a student-built Turkish satellite. UWE-2 is on 437.385 MHz, 1200 bps Ax.25 packet Universität Würzburg Experimental-Satellit2 BEESAT is on 436.000 MHz CW […]

Bouncing APRS packets off the ISS…

September 22, 2009 | Amateur Radio, Amateur Satellite | By: Mark VandeWettering

My wife mentioned to me that there was a visual pass of the ISS this evening. Wow, is she awesome or what? She found out about it by subscribing to the twitter feed “twisst”, which is apparently automated, and will send you messages when a ISS pass is about to occur. This pass had a […]

Is mobile operation of a ham radio really safe?

September 21, 2009 | Amateur Radio, Rants and Raves | By: Mark VandeWettering

The federal government is currently considering the possibility of legislation banning the use of cell phones and texting. I’m mostly okay with that, because, quite frankly, it’s obvious that people aren’t very good at operating a cell phone or texting while driving, a fact which has been reinforced by study after study. But while many […]

High altitude balloons – Hack a Day

September 19, 2009 | Amateur Radio | By: Mark VandeWettering

Courtesy of hackaday, here’s a link to a list of nifty high altitude balloon projects: High altitude balloons – Hack a Day.

Why work for a game any company like this?

September 16, 2009 | General, Rants and Raves | By: Mark VandeWettering

This link is making the rounds of a couple of different mailing lists I’m on. Activision games to bypass consoles – News at GameSpot When he wasn’t promoting the company’s games or technology, Kotick was celebrating its laserlike focus on the bottom line. He pointed to changes he implemented in the past as being particularly […]

Codec2 – Open Source Low Bit Rate Speech Codec

September 16, 2009 | Amateur Radio | By: Mark VandeWettering

David Rowe is working on a very cool project that should be of interest to hams with an interest in digital communications. He’s creating an open source, low bit rate speech codec. His target is a usable 2400 bps codec that is free from patent issues, and that can be used in situations similar to […]

Upcoming launch of SumbandilaSat

September 14, 2009 | Amateur Radio, Amateur Satellite | By: Mark VandeWettering

It looks like the launch of the South African amateur satellite is on track! The launch of SumbandilaSat is on track for 15 September 2009. In an interview with SA AMSAT, Johan Erasmus, SunSpace systems engineer speaking from Baikonur, said that the satellite travelled well and that all system performed to specification during the testing […]

Project Icarus

September 13, 2009 | General | By: Mark VandeWettering

A group of MIT students did a high altitude balloon launch. That’s really not all that unusual: radio amateurs do similar launches several times per year. What is unusual is the price tag: $150 total. They used an inexpensive Canon camera running the CHDK firmware to snap images, and a cheap no-contract Motorola phone to […]


September 8, 2009 | General | By: Mark VandeWettering

HAKMEM is a legendary technical memo from MIT that’s packed full of interesting bits. On this occasion, I ran across item #175, which you can find here: HAKMEM 175 This is a little chunk of code which given an integer, computes the next highest integer with the same number of one bits. This code is […]

Parrondo’s Paradox

September 7, 2009 | Math | By: Mark VandeWettering

I was reading Nahin’s Digital Dice, which I bought a while ago but which I didn’t really dive into deeply, and he had a nice exposition of Parrondo’s Paradox, which is very neat. Here’s the idea: We are going to play two different coin tossing games. In each case, if we win, we gain one […]