I’ll be taking two classes again this fall in the continuing pursuit of my PhD in Computer Science at Ole Miss. I’ll also be teaching CSci259/390 (C++) on Monday and Wednesday nights.

Sometime in late September or early October I’ll be taking my comprehensive exams, the first of three major milestones in the PhD process. There are four exams, covering Systems, Algorithms, Programming Languages, and Software Engineering. I’m not worried about them, but I’ll be glad when they’re over. Right now I feel guilty if I do anything other than study for “comps.”

I’ve recently finished my Small Wonder Labs SW-40+, a small Morse code radio for the 40m ham band. I’ll be posting about it soon. There are also several other ham radio and electronics projects I need to post about. Back in the spring I presented a tutorial on microcontrollers at the ACM Southeast conference.

James and I have another backpacking trip tentatively planned for September, which I’m really looking forward to. We had intended to go in the spring but got busy and never planned anything.

Of course, I need to post an update about Luke and Liam, which I will try to do soon.

Obviously, I plan on posting to my blog a little more frequently. I’ll continue to post shorter stuff over on Twitter.

I’m now up to Experiment #16 in Make: Electronics; about half way through. I’ve learned a good bit, even though the book is definitely aimed at newbies. I have skipped a couple of experiments that didn’t seem like they offered enough new experience for the amount of effort they would require.

I would recommend the book to anyone with one disclaimer: be prepared to spend a lot on tools and supplies. I’m also not terribly fond of the author’s recurring intruder alarm example. I feel like he could have come up with a better project. On the other hand, I don’t know of a better hands-on, beginner’s guide to electronics.

For now, I’m suspending my efforts on the book to finish up my DDS-60 card. More on that soon.

I got a Circuit Specialists Soldering Station for $45. It’s a 40 watt temperature-controlled station. I have the one with the digital temperature display, but they have an analog version for $5 less. The analog one is more than accurate enough, but I like the digital look. It comes recommended by others, and I have no complaints. The grip on the iron gets a little hot, but not to the point of being uncomfortable. I’ll probably upgrade eventually, but I expect it’ll be several years. You could probably get by with a non-temperature-controlled iron, but I think this one is definitely the best bang for buck.

For through hole work I use a 1.2mm chisel tip. Most people would probably use the next size up, but I enjoy the extra control the smaller tip gives you. For surface mount work I use a 0.8mm conical tip.

I decided on 63/37 Kester 285 solder, in 0.031″ diameter for through hole and 0.015″ diameter for surface mount. The 63/37 refers to the percentages of tin and lead in the solder. The 285 refers to the type of flux. Flux helps the solder stick to the objects you’re trying to solder. While solder sticks to metals like copper very well, it doesn’t stick to oxides very well. Unfortunately, the high temperatures involved in soldering cause accelerated oxidation. Flux helps prevent oxidation and also serves as a wetting agent, causing the solder to flow. Some fluxes must be cleaned off the board after soldering. I don’t have time for that, so I settled on Kester’s 285, the most active flux I feel comfortable leaving on a board. There are also “no clean” fluxes, but they tend to not perform as well. Especially while you’re learning to solder, stick with something like Kester 285. You can also get lead-free solder, but it’s not beginner friendly either.

I bought my solder from Digikey in 1lb. spools. It runs $20-30 per spool.  It’s hard to find good solder in small amounts. Radio Shack has small quantities of solder, but I have no idea if it’s any good. If you’re just getting started in this hobby I’d be glad to give you some solder. There’s no way I can use it all before it goes bad. (This type of solder has a shelf life of three years or so.)

I also have a flux pen, but I’ve only used it a couple of times when hand soldering surface mount ICs.

You need a way to clean your soldering iron’s tip. Most irons come with a cheap sponge that you wet. I use a Hakko 599B tip cleaner. It looks like a pot scrubber, but it has flux on it that cleans your tip. It also doesn’t drop the temperature of your tip like a wet sponge.

Sometimes you need to remove solder. There are two basic ways to do this: a desoldering pump or desoldering wick. The pump seems to be the old standby, but I’ve had way more luck with wick. I never use the pump these days. I use TechSpray wick and it does a good job. I use size #3 for through hole components and size #2 for surface mount.

I use Xcelite 378M pliers and 170M shear cutters. Amazon has them for $14 as a pair. You can make do with a small pair of regular pliers, but cutters like this are virtually essential. Home Depot carries an identical set under the Cresent brand.

Good lighting is essential for this sort of thing. While not ideal, I use a Petzl headlamp when soldering. Magnification is also important. I have a 10x jeweler’s loupe that I use for checking joints after the fact. I’d love to have a lamp/magnifier combo that clamps to my desk, but they’re expensive, and I’m sure my kids would find a way to break it. One of those magnifier visors would be nice too.

So, yes, getting setup to solder is a little on the expensive side, but it’s not bad compared to a lot of hobbies, you don’t have to buy it all at once, and it’s a good skill to acquire. Let me know if you have any questions.

Dummy load in vise, on desktop.

So, what the heck is a dummy load? When you’re testing a transmitter, you can’t just transmit without anything connected to the output. You could fry your final amplifier. So you need a dummy load that presents the correct impedance, 50 ohms in most cases. As it just so happens, I’m getting ready to build a transceiver, and will need a dummy load for testing. Also, this particular dummy load involves several surface mount (SMT) parts, and I wanted a little practice with those before beginning my next project, the Softrock Lite II 30m software-defined receiver.

This kit was designed and sold by NorCal QRP, a low-power (QRP) ham radio club based in Northern California. They have put together several kits over the years. They actually retired this kit a couple of years ago, but I inquired on the qrp-l list and someone had one they weren’t planning on building.

Some hams are intimidated by surface mount (SMT) components, and rightly so; they’re pretty small. Have a look below. The small black thing to the right of the penny is a 2.2 kOhm SMT resistor. SMT components come in different sizes. This size is referred to as 1206, which means it’s 0.126″ × 0.063″. It’s one of the larger sizes of SMT components.

As it turns out, soldering SMT components isn’t too bad. I used a small tip on my soldering iron and small solder (0.015″ diameter) and had no problems. There were no SMT integrated circuits on this project, but there would be on my next project.

Tonight I started on another SMT project, but using solder paste, a griddle, and an embossing gun instead of solder and a soldering iron. More on that later.

After checking out the reviews on Amazon I settled on Getting Started in Electronics by Forrest Mims. It has glowing reviews, many reviewers crediting Mims for jumpstarting their career in electronics. It’s also very short, at 128 pages.

I’ll be honest, I was disappointed. I’m probably a little more experienced than the target audience for this book, but not by much. While I did learn a few things, I found it to be way too high-level and not at all hands-on.

My next attempt at gaining an intuitive understanding of some electronic concepts will be via Make: Electronics. It’s a relatively new book by the guys at Make Magazine, of which I’m a subscriber. I read an interview with the author and editor a few days ago, and they actually mentioned that their intent was for it to be a modern day replacement for Getting Started in Electronics. (GSiE was originally published in 1983.) From reading about the book, it is decidedly more hands-on. While I’m sure some of it will be repetitive for me, I expect to learn quite a bit as well.

While I’m waiting on that to arrive, I’m going to read a couple of Sherlock Holmes short stories. I hope to see the new movie in the not too distant future, and I don’t want my image of Holmes’ world to be tainted by Hollywood.

While I’m very excited about the ATS-3B, I’m going to force myself to leave it alone until I finish my Softrock Lite II 30m software defined receiver and my Small Wonder Labs SW-40+ 40m CW transceiver.

I’m not sure I’ve even mentioned my Softrock Lite II on the blog before. I’ll have to do a proper post on it soon. I have mentioned it over on Twitter. It is done, as in all the parts are installed. However, I’m not able to receive any signals. The helpful guys on the mailing list tell me it needs a proper 50-ohm antenna. I was trying to use a small piece of wire as an antenna for testing purposes.

I have ordered and received everything I need to build a 30m dipole antenna that will be installed in my attic, at least for now. I’ve even cut the wire to length. I just need to solder everything and put it in the attic. I’ll probably borrow an SWR meter from one of the local hams to ensure it’s resonant on the 30m band. Hopefully the Softrock Lite will just work once it has a proper antenna. If not, I’m confident I can troubleshoot it with the help of the guys on the mailing list.

The SW-40+ is mostly done. All the components are installed on the board. However, I still need to align it, integrate the K12 keyer, and put it in the enclosure. I’ll also need to learn Morse Code before I can get much use out of it. I’ve been practicing occasionally, but I’ll have to put a lot more time into learning it before I’m good enough to try an on-air contact.

I’ve also been tinkering with AVR microcontrollers, but that’s a long-term project, so I’m content to let that sit while I build the ATS-3B.

I hope to get up a post about the backpacking trip soon. Two things are holding it up. Mostly, I’ve been insanely busy since I got back. Secondly, the memory card that has the pictures from the trip on it seems to be corrupted. I’ve ordered a card reader so I can attempt to recover them.

Last month NIST updated WWVB Radio Controlled Clocks: Recommended Practices for Manufacturers and Consumers (PDF), its guide to making and using WWVB-controlled clocks. WWVB operates at 60kHz, way down in the low frequency band. A half-wavelength antenna for WWVB would be a little over a mile and a half long. NIST also operates WWV, which broadcasts at 2.5, 5, 10, 20, and 25MHz.

Building a WWVB-controlled clock is on my list of electronics projects, but it’s not one I intend to get to anytime real soon.

The ATS-3B was designed by Steve to be the ideal radio for backpacking. He lives in New Hampshire and backpacks the Appalachian Trail often.  (ATS stands for Appalachian Trail Sprint.) I haven’t done much backpacking lately, but I’m looking to get back into it soon.

Most ham kits use through hole parts, which are easier for some people to handle. The ATS-3B uses lots of surface mount parts, allowing it to be very small. I’ve used surface mount parts on a couple of projects and actually prefer them. I’ve always soldered them by hand. Steve seems to prefer the solder paste/warming plate/embossing gun method. I’m not sure if I’d give that a try or stick with soldering by hand. Here’s a YouTube video of Steve doing it both ways.

Steve only offers ATS-3B kits periodically. I believe he’s offered them about three different times now. He’ll be offering them again sometime in late fall, and I’ll be ready. This will also be the last time Steve will offer this kit, as some of the parts he uses are being phased out. He’s already working on the ATS-4, which looks to be a very nice (though somewhat larger) radio.

The 40m ham band is a good all-purpose band. It’s open to somewhere pretty much any time, day or night, even at this point in the solar cycle. QRP means it’s low-power. In this case, around 2.5 watts. Most commerical radios put out around 100W. CW means it only does Morse code, no voice, which means I’ll finally have to learn Morse code.

The SW+ series is well-regarded in the QRP community. There are models available for the 20m, 30m, 40m, and 80m bands. The kits are put together by a guy in New Hampshire. There’s a waiting list of around two months to get a SW+ kit.

The SW-40+ board with 8 of the 16 sections installed. I've added a couple of sections since this photo was taken.

A few weeks ago I finally got a chance to start putting mine together. The instructions that come with it basically say to build the whole thing, then test it. I’ve built some smaller kits before, but this is definitely my largest undertaking thus far, so I wanted some assurance things were going right as I built it. So, I’ve been using Chuck Adams’s, K7QO, guide to building the SW-40+. By following his guide, you build a section, then test it. He has it broken down into 16 sections, more or less. Some of the previous kits that I’ve built are used for testing.

You can see all the pictures from the construction process here. I’ll continue to add photos as I go along. I’ll post an update here occasionally too. So far I’ve installed the power supply, audio amplifier, keying, muting, audio preamplifier, receiver mixer/detector, IF crystal filter, receiver mixer, VFO, and transmitter mixer sections. That’s 10 of the 16 sections.

Testing the transmitter mixer section by feeding the output of the transmitter mixer into the receiver.

A few months ago I bought a VE3DNL Marker Generator kit, but had never put it together. Chuck suggested using it to test the receiver mixer/detector section. It was a quick build, and the receiver mixer/detector section passed the test.

VE3DNL Marker Generator board is on left of SW-40+ board. The VE3DNL transmits tones every 5kHz that can be picked up in the SW-40+ receiver.

After building the VFO section I wanted to have a look at the waveform. Chuck’s guide shows a nice sine wave. A friend had loaned me an oscilloscope for another project a few months ago, so I drug it out and set it up. To make a long story short, I was never able to view the VFO’s waveform on the oscilloscope. Something is wrong with either the probe or the oscilloscope itself. However, I was able to confirm that the VFO is running at around the correct frequency with the FCC-1 frequency counter I built a while back.

I have also built a K1EL K12 keyer to put in the SW-40+. As designed, the SW-40+ can only use a straight key. I wanted to be able to use iambic paddles, so I found the K12 keyer. It handles the input from the key and outputs perfectly spaced Morse Code. It sounds beautiful. It’s a pretty cool little device in its own right. I may do a post on it at some point.

The K1EL K12 keyer assembled.

More on the SW-40+ when I get a chance to work on it.

I used my “antenna launcher” to put up about seven antennas Saturday morning. I don’t think I’ve ever done a post on my launcher. I’ll have to do that soon. It’s pretty neat.

I’ve determined that I enjoy setting up the Field Day site just as much or more than actually operating. I’m not sure why that is. I’ve already got several ideas for improvements next year.

I’ve been trying to learn Morse Code (CW) for several months now. I haven’t been spending enough time on it to actually learn anything, but watching the guys at Field Day got me excited about it again. Plus, I’ve got to learn it if I want to get much use out of the radio I’m building right now. More on that soon.

The University of Mississippi Amateur Radio Club (UMARC) will be setup in the Circle on campus from approximately 1pm on Saturday to 1pm on Sunday. We’ll have three HF stations setup, two on voice and one on CW (Morse code).

The purpose of Field Day is to practice setting up stations “in the field” and showing off our capabilities to the public. Mainly it’s just fun. For those of us without radios of our own, it gives us a chance to get in lots of quality operating time.

If you’re curious about ham radio, stop by and give it a try. If you’re not in Oxford, have a look at the Field Day Station Locator and find a club setup near you.

The standard mode of propagation for the VHF bands is “line-of-sight.” That is, in general, if you want to talk to someone via VHF, you need to be able to “see” them. Things like trees and buildings aren’t a problem with enough power, but you can forget going over the horizon without some sort of propagation enhancement such as “Sporadic E” or tropospheric ducting.

As meteors fly through our atmosphere and burn up, they produce ionization. As it turns out, you can bounce a VHF signal off of meteor ionization trails. These trails typically only last for a few seconds at best, but it’s long enough for stations communicating at high speeds to have a short conversation. Fortunately there are enough small meteors entering the atmosphere that there’s no need to track them or anything. You just aim a directional antenna at the guy you want to talk to and transmit and listen on a set schedule.

Some hams use voice or morse code for these sorts of communications, but a more surefire way is to use a high speed digital mode, such as FSK441, a digital mode written specifically for meteor scatter communications by Joe Taylor, K1JT, a ham and a Nobel laureate in Physics. The most popular ham band for meteor scatter communications is the 6m band, though it’s possible on several others.

Another, similar, mode I’d like to try is EME. It’s a little further down the list though, as it requires a much more impression station, both in terms of antennas and amplifiers.

I used plans from here. The center part is a SO-239 connector I bought at Radio Shack, and the radiating element and radials are made out of uncoated brazing rods that I procured at a farm supply store. The vertical (radiating) element is 19.3 inches long, or a quarter wavelength electrically for the 2m band (144-148 MHz). The radials are slightly longer.

It works quite well. When I tune my radio to the local National Weather Service station I get a few S units of improvement over the rubber ducky antenna. Each S-unit is 6dB, so that’s quite an improvement. Using this antenna I can get into the local repeater when I didn’t have a prayer with the rubber ducky. Of course, now I use my Diamond antenna mounted on the house.

I intended to borrow an antenna analyzer from a local ham to see how close to 50 ohms I had managed to get. I never did, but I’ll be sure to do it when I borrow the analyzer for another project. Given the way it performs, it has to be relatively close.

A few more pictures here.

Most of my “interesting stuff” is ham and/or electronics related. I got a soldering iron for Christmas, and I’ve put together a few kits and I’m in the process of putting together a few more, including an SDR receiver and a Morse code transceiver. I’ve also started tinkering with AVR microcontrollers.

During the holidays Luke got in the habit of going to sleep really late. After the holidays, he kept it up. I’d guess than during January, his average bedtime was 10:30pm. That doesn’t leave much time for dad to play with his toys. Luckily, he’s been going to sleep around 9pm the last week or so. He slipped a little tonight, but I’m not too worried about him regressing.

In other sleep-related news, we had been letting Liam sleep in his swing for the past few months. We knew it was a bad habit to form, but he slept so well in it. He went from getting up 2-3 times a night to 0-1 times a night. This week we finally decided it was time to break the habit. The first few nights were rough, but last night he only got up once. Luke got up once until he was about 15 months old (Liam is only 6 months old), so I don’t guess we can ask for much more.

So, if the boys keep up their good sleeping routines, you should be seeing a lot more posted here.

The antenna he had come to help me put up was a Diamond X50NA. It’s a 2m/70cm antenna. 2 meters is a popular VHF ham band, and the local club has a 2m repeater. The club also has a 70cm repeater less than a mile from my house. I don’t currently have a radio that supports 70cm, but when I get one, I don’t have to worry about an antenna.

The X50NA is not a small antenna. It’s over five and a half feet tall. I needed a substantial support to install it on. Also, at VHF frequencies and above, propagation is essentially line of sight, meaning that height is very important.

Luckily, when my grandmother moved a few years ago, she didn’t need all of the tower her TV antenna was on. My dad had taken the parts she didn’t need and stored them for a “rainy day.” (God bless pack rats.) So the base of my antenna support would be two sections of what appear to be Rohn 25G. On top of that we mounted a 10′ section of 2″ pipe using muffler clamps. Inside that, we placed a 10′ section of 1 1/2″ pipe restrained using a hose clamp. And on top of all that went the antenna. I estimate the base of the antenna is up about 25 to 30 feet.

I feed it with around 60 ft. of LMR-400 (PDF), a low-loss coax. Coax tends to be pretty lossy at VHF frequencies, so I wanted to go with the good stuff. At 147.33 MHz, the frequency of the local repeater, LMR-400 has a loss of 1.52dB (29%) per 100ft. The next best stuff, RG-213, has a loss of 2.50dB (44%) per 100 ft.

As you may recall, the only radio I have at the moment (that’s put together anyway) is a Yaesu VX-170, a handheld 2m transceiver. To reliably talk on the local repeater I had to walk up on the hill behind my house. When the repeater was having a bad day, as it sometimes does, I would even have to hook it up to my quarter wave ground plane antenna that I built to get into the repeater.

Now I can reliably talk on the repeater, even with my radio turned down to low power (500mW). I can also talk on the Pontotoc and New Albany repeaters, though I’m told I’m a little scratchy on the New Albany one. I had hoped to be able to hit the Batesville, Mooreville, and maybe even the Grenada repeaters. I still feel like I ought to be able to hit the Batesville repeater, I but I don’t even receive it well here for some reason. The Mooreville repeater was always a little optimistic, as Mooreville is all the way on the other side of Tupelo, but it’s on a tall tower, and I can hit it from inside my car halfway between Pontotoc and Oxford.

I have two theories as to why my antenna isn’t working as well as I expected it to:

1. My coax connectors weren’t installed correctly and I’m experiencing loss. I’m using N connectors, which are better than the standard UHF connectors, but I have no experience installing them. (Not that I have any more experience installing UHF connectors.) A couple of guys around here have equipment I could have borrowed to measure the loss through my coax, but I didn’t make those arrangements in time, and now I’d have to get up on my roof and lower the antenna. I’ll definitely do it when I move one of these days.
2. Power makes a lot more difference at VHF frequencies than I gave it credit for. At high power, my radio only puts out 5 watts. Your average mobile VHF radio can do 50W, a 10dB difference. One of these days I’ll remedy this “problem,” but its not near the top of my list.

So, did I spend entirely too much time and money to get an antenna up for 2m? Probably. I could have done it a lot cheaper and with a lot less fuss. However, this setup should be all I need for a while.

Our antenna project was interrupted early on to take Cassie to the emergency room. She was sterilizing some pacifiers with boiling water, and when she took the pot off the stove the handle broke. She now has decent sized second degree burns on her stomach and left leg. They gave her a tetanus shot to prevent infection, some high-powered pain medicine, and some cream to put on the burn. She’s handling it very well. I would definitely take advantage of the situation more than she has. Lucky for me, she isn’t.

On any normal day Luke would have been right beside Cassie. Thankfully, yesterday wasn’t a normal day, and he was in the other room with my mom. Interestingly, one of my high school classmates was Cassie’s nurse in the ER. There were only 56 of us, and Belmont is over 100 miles from Oxford. I’d say the odds are low.

Yesterday afternoon Cassie was feeling well enough to go to the Southern Living Idea House in Taylor. My mom has been reading Southern Living for as long as I can remember, and she and my dad are planning to renovate their house next year. It was pretty interesting.

When we arrived they had a nice pileup going on 20 meters. I called Randy and told him what frequency we were on. He could hear all the stations calling us, but couldn’t hear us. That most likely meant he was in our skip zone. Later, after the 20m band died, we moved to the 40m band. I called Randy again, but he still couldn’t hear us. We never got a chance to try the 80 meter band, but I expect it would have worked, as the size of the skip zone decreases with frequency. While I was there they made contact with a station on Martha’s Vineyard, and a station near Aspen, Colorado, operating with less than five watts, among others.

Today I operated the special event station during the late afternoon. When I arrived things were slow, so I switched over to 80m and Randy and I made contact without a problem. Things remained slow the remainder of my shift. My signal was getting out just fine, as the station I talked to in Manitoba, Canada, could hear me well. Maybe most everyone was still at work?

The new repeater will supplement our existing 2m repeater on 147.33 MHz. The club also recently installed an APRS digipeater on top of Bishop Hall on campus.

Unfortunately, I don’t have any 70cm capable transceivers currently. I can listen on my scanner, but that’s it. Hopefully I can remedy that by the end of the year.

Anderson Communications' "tower jocks" carry the antenna to the top of the tower.

Continue reading for more photos of the antenna install and a propogation map.

Repeater antenna being installed on top of the hospital's tower.

The view to the south from the top of the hospital. (The view back toward town is blocked by pine trees.)

A propogation map showing the expected coverage area of the new repeater. (Image courtesy Rick, N5RB)

I operated some this morning, and will operate again Friday afternoon from 3-5pm. This morning I made contacts with stations in California, Arizona, New Mexico, Colorado, Pennsylvania, New Jersey, New York, Rhode Island, and Cuba, among others, primarily on the 20m band.

Unfortunately I don’t have an HF radio yet, so I can’t make contact with them myself.

Yesterday I got a call from a fellow amateur radio guy here in Oxford. The St. Helena Parrish Emergency Operations Center in Greensburg, LA was looking for some hams to deploy down there for the storm and its aftermath. Unfortunately I had to decline because of Liam. It would have been fun.