This perfboard was designed to fit into an Altoids tin.

Sunday, at the museum, Jim, K8ELR, brought down all of the soldering irons he’d ever purchased to try them out in building the little QRP transceiver kit he just bought. The . . . → Read More: I Finally Have a Mini Solder Pot]]> Two years ago—almost to the day—I wrote about making a min-solder pot to tin toroid leads. Well, now I finally have one.

Sunday, at the museum, Jim, K8ELR, brought down all of the soldering irons he’d ever purchased to try them out in building the little QRP transceiver kit he just bought. The results of that may be the topic of another blog post, but one of the irons he had was a 25 W Weller pencil iron.

“Aha,” I thought, “this would be perfect for the mini-solder pot.” I convinced Jim to let me take the iron home with me and convert it by noting that his kit had several toroids whose leads were going to need stripping and tinning.

I  did that tonight. I carefully hacked off the end of the soldering iron tip and filed it down. Then, I carefully drilled a 5/64-in. hole about 3/16-in. deep. I then widened the hole to 3/16-in. The hole in the tip wasn’t exactly centered, but I didn’t break through the sidewall of the tip.

I plugged in the iron, heated up the tip, and filled it with solder. I dipped a short piece of enameled wire, and a couple of minutes later, I had a perfectly tinned lead! It had worked like a charm. In about 15 minutes, I had eliminated one of the most odious tasks associated with kit building. This is going to be well worth the effort.

Uh-oh! You dutifully cleaned off all of your vacuum tubes to make them shiny and the numbers came off with the dirt! Pat AA6EG saves the day – “Put the tube in the refrigerator, cool it down, then bring it into a warm room temperature environment. . . . → Read More: Tube Tip]]> Here’s a great tip from the 6/23/10 ARRL Contest Update:

Uh-oh! You dutifully cleaned off all of your vacuum tubes to make them shiny and the numbers came off with the dirt! Pat AA6EG saves the day – “Put the tube in the refrigerator, cool it down, then bring it into a warm room temperature environment. There will be moisture condensing on the glass envelope, sometimes leav[ing] a readable outline of the tube numbers.”

If you have any tubes at all in your junkbox (mine’s more like a junk closet), you’ll undoubtedly have some that you can’t identify.

One cool thing that someone pointed out is the Processing language. This looks like a very cool thing that I’ll have to . . . → Read More: More on Microcontrollers]]> Despite the low price of the TI Launchpad, most of the AMRAD folks thought that this was hardly an Arduino killer. They pointed to all the users and support that the Arduino has.

One cool thing that someone pointed out is the Processing language. This looks like a very cool thing that I’ll have to play around with. According to their website:

Processing is an open source programming language and environment for people who want to create images, animations, and interactions. Initially developed to serve as a software sketchbook and to teach fundamentals of computer programming within a visual context, Processing also has evolved into a tool for generating finished professional work. Today, tens of thousands of students, artists, designers, researchers, and hobbyists who use Processing for learning, prototyping, and production.

One of the projects they pointed to is the “Poorman’s Oscilloscope.” This project uses an Arduino as the analog front end and Processing as the display back end. I think that with a little thought and programming you could also create a simple spectrum analyzer and make your own waterfall display. (I’m thinking that I could perhaps write a Mac version of Argo with Processing.)

According to the Hack a Day blog post:

Each Launchpad device comes . . . → Read More: TI Makes a Run At Arduino]]> On the AMRAD Tacos mailing list, Andre, N4ICK writes, “Who couldn’t use one of these?” One of these happens to be the Texas Instruments’ Launchpad, a development platform for their low-cost line of microcontrollers. The kicker is that they’re selling this puppy for only $4.30.

According to the Hack a Day blog post:

Each Launchpad device comes with a whole lot of goodness. In addition to the board itself you get a 0.5 meter USB cable, two pin headers and two pin sockets for the pin breakout pads, two different MSP430 microprocessors (MSP430G2211 and MSP430G2231), and two free IDEs; Code Composer Studio 4 and IAR Embedded Workbench Kickstart (note that the latter has a 4K or 8K code limitation depending on the processor used).

Sounds pretty cool to me.

I started out in the TAPR forum, but only spent a couple of minutes there. I quickly switched over . . . → Read More: Friday at Dayton Was Forum Day]]> Friday at Dayton was “forum day.” By that I mean that I attended a slew of forums and could have attended several more. That left little time to actually scour the flea market or visit vendor booths.

I started out in the TAPR forum, but only spent a couple of minutes there. I quickly switched over to the ARRL Public Relations forum. There I got to meet Diana Eng (see previous post). I also:

En route to the Teacher’s Forum, I passed by the Antenna Forum, which looked to be very popular. There were guys standing out in the hallway trying to hear the presentation.

The Teacher’s Forum has been moderated by Carole Perry, WB2MGP, for as long as I can remember. She always has good speakers. This year, the lineup included Gordon West and Bob Heil.

One idea that I picked up is to use a flashing light or LED to demonstrate the idea of duty cycle. By hooking it up to a variable duty cycle oscillator, you could vary the amount of on time versus the amount of off time, and this would make a very good visual demonstration.

This year’s presenters mostly talked about teaching kids. This fall, I plan to teach a class for seniors. If it goes well, I’m thinking that I could talk about that class at next year’s teacher forum.

In the afternoon, I attended the Software-Defined Radio Forum. This forum was also packed. We first heard about the new FlexRadio 1500, which is a $650 SDR. Its output is only 5W, but this looks like a real bargain.

Next up was Lyle, KK7P, from Elecraft. He gave us the Elecraft perspective on what an SDR is and what it’s not. It was interesting, but not very technical.

After Lyle, the TAPR VP (whose name and call I forget) talked about developments with the SDR projects at TAPR. My initial impression is that while all of these developments are well-done, it’s still much less expensive to simply buy a Flex 1500. I haven’t checked the specs, though, to see if they are comparable.

Finally, there was a talk on MacHPSDR, a native Mac implementation of a receiver for OpenHPSDR hardware. I wish that I’d been able to stay, as I am a Mac person, but I had to leave. Despite the availability of this software, you really do need to have a PC to run a software-defined radio. I don’t expect this to change in the near future.

Well, that was certainly enough for one day. On Saturday, there were some equally interesting forums, including forums on RTTY, SSTV, antenna-modeling software, and the AMSAT forum. Despite this, I decided to not attend a single one and walk the fleamarket and visit vendor booths. More about that in the next post.

I know this should be a simple answer, but I’m having a hard time finding it. I am interested in building a EFHW coupler similar to the one on AA5TB’s site. He uses #22 AWG magnet wire.

I’m interested in using something less stout which I have on hand (e.g., . . . → Read More: Good Advice on Toroids]]> On the QRP-L mailing list, a ham asks:

I know this should be a simple answer, but I’m having a hard time finding it. I am interested in building a EFHW coupler similar to the one on AA5TB’s site. He uses #22 AWG magnet wire.

I’m interested in using something less stout which I have on hand (e.g., #27 AWG magnet wire). Is there a calculator to determine how this would affect the number of turns on the transformer, or am I incorrect in thinking that it would make a difference?

Diz, W8DIZ, replied:

No calculator that I know of.

1. Smaller wires have less current capacity before heating – bad thing.
2. Smaller wires have less capacitance between windings (if same # of turns) – good thing.
3. Wire size (for all practical purposes) does not determine inductance.