Brass Straight Key

Posted on July 26, 2014 at 11:36 am

IMG_20140726_112847 I just finished working on my first straight key. This is my first time working with brass, and it went fairly well. The brass polished up nicely, and according to my multimeter, it works properly too! The mortises aren’t as clean as I would like since the walnut burl has funky grain, and based on the angle of the axle, I apparently don’t have as square a drill press as I thought. Overall it looks great though, and I’m happy with the results. Now I just need to finish building a radio so I can actually use it!


ADS-B Antenna

Posted on May 18, 2014 at 7:53 am

adsb-mapNathan & I built a slim-jim style antenna tuned for 1090 MHz a few weekends ago for ADS-B reception. What is ADS-B you ask? It’s a signal transmitted by a growing number of airplanes containing a variety of information, including the gps position and altitude.
Continue reading ADS-B Antenna…

First two antennas are up!

Posted on April 13, 2014 at 6:43 pm

IMG_20140413_164534The first two antennas are on the workshop roof with the help of my little helper Nathan and my big helper Sam. Sam got on the roof yesterday and mounted the antennas for me; I got most of the way up the ladder when my knee told me that going further was a terrible idea. The cables were just sort of dangling afterwards, so Nathan & I got to work today. After some knee stretching last night, I was able to get up and down the ladder reasonably alright today to attach the coax to the wall; it at least wasn’t shaky like it was yesterday. Continue reading First two antennas are up!…

Dual band (2m/70cm) yagi with duplexer

Posted on April 5, 2014 at 7:35 pm

IMG_20140405_191752The second project of the day was a dual band antenna to try to hit amateur satellites with. This particular one is 2 m & 70 cm. The construction is 1/8″ brass rod with a small duplexer. There are no results to report so far, other than we were able to hit a local 2 m repeater with it. There was one pass of the satellite SO-50 this evening, but we didn’t get anything. We were also in the house and without a good compass, so it doesn’t count. The construction was fairly simple, and some reference sites are listed below. It should have a reasonable amount of gain, and the duplexer should be effective at splitting the signal between the bands, and it should be tuned correctly, but I don’t have the proper tools on hand to test any of that. One of these days I’ll get an oscilloscope, a signal generator, and an SWR meter, and I’ll be much better able to test a lot of these things at that point.

IMG_20140405_191818For today though, it was a fun project, and my first attempt at surface mount soldering. Future plans are to do some more testing in the 2 m and 70 cm bands with other ground based radios at both 1 and 5 watts to try and verify the duplexer is functioning, and an outdoor test to try to hit SO-50 once we’re sure the antenna is working.


Quatrefoil Helical Antenna Project

Posted on April 5, 2014 at 6:49 pm

qfhSay what? A quatrefoil helical antenna is a type of mostly omni-directional antenna that, in this instance has about 3.6 dB gain to the horizon at 137 MHz. Why would you want one? As it turns out, there are 3 NOAA satellites that transmit images in an analog mode called APT as they orbit the Earth. NOAA-15 on 137.620 MHz, NOAA-18 on 137.9125 MHz, and NOAA-19 on 137.100 MHz. Continue reading Quatrefoil Helical Antenna Project…