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Finished and installed antenna!

It didn’t take long after my first successful attempt at receiving weather satellite broadcasts for me to realize that I would need a much better antenna.  I had been using a 1/4 wave whip with a 4-wire ground plane.  There performance out of this antenna was poor.  I read up on QFH (Quadrifiliar Helix antennas) from many of the high quality posts from around the world.  I took what I could from these implementations, and did my best with the supplies I had available.

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Counting bubbles during secondary fermentation

For a while now, my friends and I have been brewing beer at my house.  I was inspired by an old Sparkfun tutorial about a bubble logger for Nate’s terrible wine.  I figured that while logging bubbles is interesting and all, wouldn’t it be more useful to have real-time information on the fermentation process?  I basically copied the optical gate method of counting bubbles, added a sensitive pressure sensor, and an AVR development board (Yes, Arwen, that’s your old TekBots board! ).  Read more…

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One of my first NOAA APT satellite images! (click to learn more)

The National Oceanic and Atmospheric Administration (NOAA) manages a few satellites in low earth orbit.  There are three actively transmitting APT signals at the moment, NOAA15, 17, and 18.  Each of these satellites passes overhead a few times a day.  I’ve been interested in learning how to receive their signals for a while now, and I’ve finally succeeded!

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Amplifier breakout board

I’ve finally gotten around to assembling a breakout board for the Skyworks SKY65116 UHF amplifier.  It’s really amazing how the state of the art in RF ICs has advanced.  They can still be on the expensive side ($6 at digikey), but still relatively cheap when you consider the cost of all the support parts that it takes to build an amplifier from a RF transistor.  This particular amplifier has a 50 ohm input and output, and 35dB of gain.  It works from 390Mhz to 500Mhz, which means its perfect for the 70cm ham band.  The breakout board is stupid simple, copied directly from the evaluation board schematic in the datasheet,  but I’ll include schematic and design files anyway. Read more…

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My, my... Than's TINY

I decided to try my hand at QFN soldering yesterday.  I was really nervous about it, it just seemed like the kind of thing only a robot or an expert can really pull-off.  I’ve seen it done many places online and everyone said that it was doable.  Well, here’s another voice in the chorus: It is possible with hobby-grade equipment. Read more…

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Transciever enclosure

It has been a while since I finished the transceiver modules, and I how now used them in an actual application.  But, before I talk about that, I’d like to show some pictures of the process I used to put them into enclosures.  I had some of these cast aluminum enclosures lying around, so I thought I’d use them.  They’re a little on the heavy side, as the completed weight is around half a pound, but it’s well within the carrying capacity of my Kadet. Read more…

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Finished puzzle box

This project was inspired by the “Reverse Geocache Puzzle Box“, an idea that has been duplicated a few times.  For Christmas this year, I drew my brother-in-law, Scott.  I know that he appreciates hand-made gifts, and my idea of hand make is almost always electronics related.  I thought for a while about a gift I could give that was hand-made, but appropriate to his interests.  While I wouldn’t say he’s interested in Geocaching, per se, but I know he will appreciate the destination.   Read more…

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Transceiver breakout boards

I’m just finishing up my last class ever!!!  (for credit, anyway.)  It was a really fun, mostly because I decided to have fun with my last class, and make it a 4/5 (undergrad/graduate).  This meant that it was much easier and less theory-heavy than those that I’m used to.  Anyway, as a grad student, I was expected to do something extra, and I decided to make a RF transceiver module.  I looked around for a little while, and I settled on the Microchip MRF49XA.  In general, it’s a nice chip.  It has about the same capability as the Micrel MICRF6xx modules that I’ve used in the past.  The Micrel modules cost $20/ea. and the Microchip IC is around $3.  I was able to make the whole breakout board for the MRF49XA for less than the Micrel module alone.  One of these days, I should dig out my notes from the Micrel project and post them, but I digress.  I noticed a distinct lack of programming information using the MRF49XA, so I’m posting not only my schematic and PCB, but the software library I wrote for the Atmel AVRmega. Read more…

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I’ve decided to move spectrum analyzer posts onto their own page.  I’ve been getting complaints from approx. 25% of my readership (hi, Katie) that I’m crossing the line to “too nerdy”.  So, I’ll let you opt-in to hearing about it.  The page is available under the title banner, near the “about” and “thesis” page.  I’ll write sub pages for each module.  Unfortunately, I don’t think there’s a way to make an RSS feed of changes to this page, so if you’re interested you’ll just have to check in occasionally.  I’ll also post when it’s all done, so there is that to look forward to.  Anyway, that’s all.  :)

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IF Amplifier cooling down

I’ve decided to hold off posting spectrum analyzer modules until they’re complete.  I’ve been collecting tons of pictures along the way, so hopefully the post for each module will be interesting and visually appealing.  With that in mind, I can’t post about any of the modules with the exception of this one.   Read more…

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