Our first of the Luna Lazzzor Talk Series, Jon Santiago will tell us about his experiences with Sustainable South Bronx, and their mobile FabLab.

When: Monday, July 12th at 8:00PM
Where: NYC Resistor
Admission is free.

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QRSS is a term used in ham radio to mean “very slow speed morse code”. QRPp means “using a very low power radio transmitter”. What happens when you combine these concepts? Small, simple, radios that can communicate over thousands of miles using about the same amount of power as a TV remote control.

The radio shown above is based on a kit by Hans Summers, G0UPL, that I picked up at the Four Days in May QRP convention. It uses a single-sided circuit board, with three transistors, one crystal, five toroids, a basic microcontroller, and a handful of resistors and capacitors. I added a 5v regulator, an LED to show the keying activity, and put it in an Altoids tin. The whole thing probably cost about $25 in parts, and took one evening to assemble.

After building it and tweaking it to get it on exactly the right frequency, I hooked it up to the dipole on the roof of NYC Resistor, and flipped on the power switch. My 100 milliwatt signal went up into the sky, bounced around between the ionosphere and the ocean a bit, and was picked up by a radio operated by Johan, ON5EX, in Belgium. He runs what is known as a “grabber” — a radio and computer combination that monitors the QRSS portion of the 30m band, converts the signals into digital spectrographic images, and publishes them on the internet.

Here is a screen capture from Johan’s website shortly after I powered on my transmitter. It shows about 100Hz of spectrum (frequency is on the vertical axis) over 11 minutes (horizontal axis). My signal is in the center of the graph. It’s my call sign, W2VV, sent repeatedly in morse code (·–– ··––– ···– ···–) at about 10.140015 MHz. If you listened to this signal as audio, you would mostly hear static. The horizontal lines you see in the graph would come out as tones. The higher the line, the higher the pitch of the tone. My signal would sound like a tone that changes pitch ever so slightly up and down as the dots and dashes are sent. However my signal would probably be so weak as to be inaudible through the static. It is only discernible when converted to visual form and then compressed over a long period of time.

Belgium is about 3600 miles away from New York, which means this transmission achieved an amazing power efficiency of 36,000 miles per watt. Also, it occupied just a tiny sliver of bandwidth — only 5Hz, meaning many other people could share the same range of frequencies without interfering with each other. However you don’t get something for nothing in life, and the tradeoff in this situation is that very little information was sent. It took six minutes just to send my four-character callsign. Still, that’s not a bad deal for a $25 radio that fits in your pocket.

Visit my Flickr page for more photos of the build. Better yet, come to our Ham Party on Saturday and see it for yourself! And if you can’t make it to our place, visit one of the hundreds of other ham radio clubs across the country hosting public events this weekend in honor of ARRL Field Day.

72/73, Dave W2VV

This past Sunday, DJ Eric Beug took the ham radio for a test drive. As Dave Clausen, W2VV made Morse code contacts on the air, Eric remixed the ham radio’s audio into dance music. Eric will be DJing from 11pm until 1am at our Field Day party, Hackers and Hams Unite! on June 26th.

In addition to the awesome prizes from Adafruit and Makerbot we will also be giving away 3 copies of Make: Electronics, 3 copies of Getting Started With Arduino, 3 copies of the current issue of Make, and… drum roll… 1 Make: Components Pack 1.

Here is a video of our 10pm demo: Using a low power amateur radio transmitter and a simple light bulb receiver circuit, we see how radio waves and electromagnetic induction transmit energy and signals wirelessly through the air. We also see how dipole and Yagi antennas radiate their energy in different patterns.

Want to learn to create 3D models, but find the user interface for most 3D modeling programs too infuriating? OpenSCAD may be for you! And we're teaching a class on how to use it on Sunday, June 27!

OpenSCAD is "The Programmers Solid 3D CAD Modeler." Rather than learn tricky user interfaces and navigate seemingly endless obscure menus, OpenSCAD uses a simple scripting language to generate 3D models from either existing or new 2D drawings. We'll start in 2D (great for creating designs for the laser cutter) and move into 3D modeling (perfect for MakerBot!).

A basic understanding of computer programming is helpful but not required. Sign up at EventBrite today!

Inspired by the upcoming 2010 ARRL Field Day event, we finally got off our duffs and set up a real amateur radio station at the resistor clubhouse. We now have a 60 foot long dipole on the roof, an antenna tuner, a couple of transcievers (one 100W and one QRP), a CW key, and a TNC for using digital modes with a laptop. With a few hours of operating under our belt, our logbook shows contacts with stations in the US, Canada, Europe, and South America, using phone (voice), CW (morse code), and PSK31 (digital).

The best part of our station is how little QRM (man-made noise) our antenna picks up. When we first put the station on the air, I thought something wasn’t hooked up right. Being in the middle of a densely-populated area, I expected to hear horrendous noise from power lines, AC motors, etc., but heard almost none. This makes tuning the bands a real pleasure.

Our club callsign is N2YCR. If you hear us calling CQ, give us a call back. We’d love to talk to you!