AA9GB's Radio Waves

I finished phase 4 of the online 1-watter build-a-thon, the IF XTAL filter.

First, I made a modification to the capacitors in my XTAL checker, as not all my 6mhz crystals in this kit were oscillating using the default values.  The checker probably still isn’t perfect, and more modifications may be required.  For $7, I’m not going to complain.  It does the job and will be useful in the future.

This build phase was straight forward and fairly simple.  No toroid cores to wind, no odd components to find, and only one resistor to search for.  I took my time and the hardest part was making sure not to overheat and ruin the crystals in the filter when I grounded the cases.

The test for phase 4 seems to work.  Not a whole lot to test yet, but I do get a bit of fuzz out the audio out when I touch the mixers input pins.

Thankfully the 2khz tone I wrote about from my phase 3 testing went away.  My board is now giving a tone just under 1khz.  This is exactly where it’s supposed to be.  I suspect it may have something to do with modifying the XTAL checker, but I did build a whole extra section, so who knows?

One quick and easy way to check tone pitch is to use a free instrument tuner program on a smart phone.  I happened to already have one loaded, and it saves time and effort over plugging in a computer and running analysis of the audio.

I noticed that Richard, N4PBQ posted on his blog wondering how to solder surface mount components (SMD) like the capacitors included with the 1Watter.

For the online build-a-thon, I’m following Chuck’s lead of using the thru hole components, but I’ve had good luck soldering SMD devices by hand for other projects.

A good pair of tweezers and magnification are handy here.  You don’t have to spend a ton of money but a 10X Triplet Loupe or an Optivisor make life a lot easier.

Dave from the EEVblog did a nice video series on soldering.  It’s worth watching the whole series, but jump to about 6:50 in the video below for a quick tutorial on one way to deal with chip resistors and capacitors.

The latest phase of the online 1-watter build-a-thon was the audio detector mixer (BFO).

This is the first time I’ve run across a binocular toroid.  Winding toroids always takedats me longer than I think it should for something so simple.  In this case stripping and tinning the wire after the fact got me.

Everything went together well, and I think the tests were successful.  It’s picking up a 6mhz xtal in my crystal checker, so it seems to work.  The tone I’m getting is more along the lines of 2 khz vs 1khz, which is hopefully not a major issue.  Up until this point, I’ve been pretty spot on to what Chuck’s (K7QO) test results say I should get.

Based on the published build sections, it will be a couple weeks until I can really test this thing.  It’s been nice to be out in the workshop (garage) building things.  Hopefully the weather warms up, as my garage heater barely kept the bite out of the bitter cold we had in WI last week.

Part of the 1-Watter build-a-thon is to check the crystals and put a matched set in the IF XTAL Filter.  This $7.18 (shipped) from China XTAL checker is just the ticket to do that.

The downside of ordering cheap things from China is that it can take forever to receive your stuff.  Just in the nick of time, my checker finally showed up in the mail, so out to the workshop I went to put it together.

Chuck has some fantastic instructions if you’re a beginner.  It’s a fairly straight forward and easy kit though.

One caveat, there are a couple of capacitors that it’s recommended you substitute.  I missed this and don’t have anything close in my junk box.  Unfortunately for me, it meant that I couldn’t get 2 of my 6 xtals I was testing to oscillate.

Well, it’s off to order some capacitors, and hopefully I can get a slightly better match than what I already have when I can check the other two crystals in my 1 watter kit.

I’m participating in the 1 watter online build-a-thon hosted by Chuck Adams, K7QO.  We’re building the Universal 1 Watter QRPp 20m Transciever over a two month period.

These little radios are getting talked up quite a bit in QRP circles at the moment.  Chuck has some fantastic youtube videos up documenting a build, and there’s also a nice article in the latest issue of QRP Quarterly.

When Chuck announced his build-a-thon, I had to see what all the fuss is about!  The best part is that another local ham is also participating, so not only is this online, but there’s a local support network too!

Magnification is needed when building this radio.  I’m under 40, have good vision, and there’s no way I could build this little kit without my optivisor.  Chuck mentions a 10X loupe in some of his text, but I don’t think he’s emphasized it quite enough!

We just finished week 2 of the build.  That gives us power, and the audio section ready to go.  Next up is the BFO followed by the IF Filter.  I have a XTAL Checker on the way from China.  It’s supposed to show up in the mail this week, so I have a bit of extra work to get phase 3 completed!

This is a really interesting way of building a kit.  Rather than following the usual “stuff all the resistors” directions, we’re building it block by block via the schematic.  Each block is tested as we go.  It’s more along the lines of how someone might breadboard out a circuit, and I’m picking up all sorts of interesting tidbits from Chuck’s methods.

If you’re interested in CW (morse code), I highly recommend joining the SKCC.  Membership is free, and it’s a fantastic way to get your operating skills up to snuff.

This weekend was one of the monthly “Weekend Sprints.”  I found an hour here and an hour there to join in the fun.  47 QSOs later, and it’s a wrap.

The basic exchange is RST, Location, Name, and SKCC number.  It’s a bit more than 5nn tu, but it’s still very manageable for those new to CW.

Beginners and QRS (slower) operators are very welcome.