brainwagon

I was pondering my laser transmitter the other day, and began to think of how I might transmit digital information from the Arduino to the remote receiver. Since I am old, I remember the old days where programs used to be stored on an obsolete audio storage medium called cassette tape. Indeed, the first storage […]

This morning I realized that somehow I had failed to listen to the latest SolderSmoke episode (#135), so during my somewhat longer than usual commute (traffic) I set it going and had a listen. And wow, some really great stuff, especially the report by Bob Crane, W8SX on the Four Days in May (FDIM) QRP […]

I was bored, and feeling stupid. So, I was scanning around looking for numbers stations. And, if you look, you shall find. Here’s one transmitting Morse code using AM, on 5.898Mhz. Not sure what this one is, but it’s not uncommon to find numbers stations on that frequency. Numbers Station on 5.898 Mhz, Morse Code […]

Over at the tymkrs blog, they’ve been learning a bit about RTTY as a digital mode, but I found their description a bit theoretical. I’d describe radio teletype (RTTY) as a popular digital mode, particularly among contesters. It encodes text as a stream of five bit code words using a system known as Baudot, and […]

I was digging around trying to find some software to help me design a magnetic loop antenna for use on VLF frequencies. I stumbled across this page, which provided a lot of interesting insights, as well as a Spice model to help you understand how they work. Magnetic Loop Antenna Theory The article clarified something […]

It’s been quite some time since I’ve hunted for any beacons, and I’ve never really payed much attention to HF pirate beacons. Typically these are solar powered beacons which are deployed somewhere in the deserts of the American Southwest, and charge during the day and transmit simple sequences of Morse characters once the sun goes […]

I spent most of the week in New York, so Field Day snuck up on me without me making any serious plans. But since Jeri has been homebrewing her own SDR I’ve been thinking more about that, and thought that I would dust off my SDR-IQ receiver and at least make some recordings of the […]

While watching TV (not very closely) I went ahead and entered the “gyrator” part of the Gyrator VLF circuit. It does indeed seem to work. No real analysis, just the circuit as I built it.

Back on June 7, there was a spectacular coronal mass ejection on the sun: Yes, I did mention this event and gave some links to VLF receivers at the time, but I’ve been thinking about this some more. As an astronomy/telescope buff, I have built simple telescopes for looking at the sun, but I haven’t […]

I own an SDR-IQ software defined radio, a Funcube Dongle (more on that later) and have built a marginally operable Softrock Lite receiver, so you might say I’m interested in Software Defined Radios. But Jeri’s tinkering with her own software defined radio has rekindled my interest in homebrewing one. I was looking for Gerald Youngblood’s […]

I was away all weekend, so I didn’t get a chance to check out my LEDs that I got from Deal Extreme last week. Tonight, I just soldered a couple of clip leads and tried it out when hooked to the linear current modulator that I built (and blogged about) before. The transmitter in this […]

I received a cute gadget in the mail the other day: a Gameduino. It’s a small Xilinx FPGA on an Arduino shield that can create VGA and sound output. It acts like a simple coprocessor, connected via the SPI bus of the Arduino. In an effort to get people started on thinking about the Gameduino, […]

This morning’s massive coronal mass ejection from the Sun got me scrambling around trying to remember details of how amateurs can monitor solar flare activity during the current solar cycle. Mark Spencer, WA8SME, had some articles on building a small monitoring station that detected SIDs, or “sudden ionospheric disturbances”. The basic idea is to create […]

KB6NU drew my attention to this article on using operational amplifiers in audio design. It’s apparently drawn from material in Douglas Self’s book Small Signal Audio Design. As someone whose really just become involved in the ins and outs of analog electronics, I find his pragmatic approach and explanations to be really helpful. Check it […]

Ever on the lookout for software defined radio designs, I was pleased to see G0NQE’s simple receiver design this morning. He offers a kit, but also offers the bare PCB board, and puts the schematic and parts list on his website. Very cool. It’s pretty much a textbook Tayloe-style switching detector, which is implemented entirely […]