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makeRF: Ten Minute Transmitter

Last weekend I was browsing the internet for radio circuits and came across an interesting design I've never seen before, nicknamed the Ten Minute Transmitter.  The design apparently originated in 1996 in an amateur radio club QRP publication.  The name originates since the original author claimed he built this transmitter and make a QSO with it in just 10 minutes time.  Impressive!

I didn't set a stopwatch to time myself, but I can tell you that I was able to slap this rig together on a breadboard and tune it up very quickly.  There are no coils to wind (unless you want to); it tunes a wide range of crystal frequencies, and it outputs an easy 500mW AM signal.  I had three crystals on hand, and was able to load up frequencies 6925 kHz, 14322 kHz and 28266 kHz without problem.

Here's the schematic:

ten minute transmitter schematic


Posted: Feb 25, 2016

Keyword tags: shortwavetransmitterqrpschematicAM transmitterelectronics500mW

makeRF: ARRL Field Day 2015

It's already been a month since the 2015 ARRL Field Day, so I better get this post up soon or else it will be old news!  The the last few years I've tried to get on the air for some portion of Field Day.  You can read about my 2013 and 2014 experiences on this site.  Each year I try to do things a little different, and this year was no exception.

ARRL Field Day 2015

For those not in the know, Field Day is an annual amateur radio event sponsored by the ARRL to encourage operators to get on the air, and make contact with as many other radio operators as possible.  People participate for many different reasons.  Some treat it like a contest, trying to bag the highest score possible.  Others, use it to test portable or emergency operations.  And, probably most people who participate just do it for casual fun.  I'm usually in that last boat even though I have in the past operated on emergency power, for fun.


Posted: Jul 29, 2015

Keyword tags: arrlfield daycwradio operating

makeRF: Dayton Hamvention 2015 Roundup

This past weekend was the 2015 Dayton Hamvention, the biggest convention dedicated to amateur radio.  I had the pleasure of attending for the first time last year and was happy to return this year.

My goals were: to pick up some components for new projects, enhance my station with some new equipment, shake hands with some of the folks I met last year, and enjoy a day trip with my father.

dayton hamvention 2015 tickets


Posted: May 20, 2015

Keyword tags: dayton hamventionham radio

Build a Raspberry Pi Powered Arcade Machine!

A few months ago I came across the project on Adafuit Retro Gaming with Raspberry Pi, and thought it would make the perfect gift for my brother-in-law.  I finally got around to building it with a few tweaks of my own.

raspberry pi arcade machine

  • 1x Raspbery Pi
  • 1x Arcade Joystick
  • 2x Arcade Buttons
  • 1x HDMI to VGA adapter (assuming you don't have an HDMI monitor)
  • 1x USB A / Micro B adapter (for Raspberry Pi power)
  • 1x USB wall wart (for Raspberry Pi power)
Other needs:
  • Monitor or Screen (HDMI or VGA)
  • USB Keyboard (for additional game buttons)
  • Speaker
  • A box/enclosure to mount the controls

Click to read more

Posted: Feb 13, 2014

Keyword tags: raspberry piarcademakeelectronics

Build an Arduino Word Clock

A few months ago I came across an interesting project, an Arduino Word Clock.  If you aren't familiar with the term, it's basically a clock that tells you the time as a sentence instead of with digits.  So instead of 10:30pm, it would say, it is half past ten.  The reported time accuracy is within 5 minutes, which is good enough for a general clock / interesting piece of art.  I decided to build one as a Christmas present for my dad.

arduino word clock

Although I read a few different designs on the web, I decided to take my own path and design my own.  I encourage you to do the same; sometimes it's easier to do things the way you want to do them and look to others for inspiration, than follow instructions to the last detail.

The general steps are: 1) Create the clock face, 2) Wire the lights, 3) Build the driver for the lights, 4) Add the clock, and 5) Final assembly.

Click to read more

Posted: Dec 24, 2013

Keyword tags: arduinoelectronicsclockRTCshift registers

Check Out My New Site:

If you are interested in radio and hobby electronics be sure to check out my new website!

makeRF logo

Amateur radio and hobby electronics are two of my favorite hobbies, and am always looking to interest others in the art.  I launched makeRF as a platform for my own self-directed learning, and to share my builds and experiments for others to try out.  I aim to present topics in an accessible format so beginners can take a stab at the projects, but also include interesting detail for those with more expertise.

Click to read more

Posted: Jun 17, 2013

Keyword tags: amateur radioelectronicsmakeDIYmakeRF

Hacking My House #1.5: When Lightning Rings

If you read my last post, you saw my schematic on how to build a musical Arduino doorbell.

After the doorbell was installed, I noticed that it rang by itself sometimes. Not often enough to be too annoying, but enough to think about correcting the issue at some point. I noticed it rang sometimes when a large appliance clicked on, like the dishwasher or central air, and even sometimes when getting a static shock on a light switch.

My annoyance level went through the roof when a large thunderstorm rolled though one afternoon. During the fifteen minutes of thunder crashing, the doorbell rang by itself six times!

So, what was happening, and how did I fix it?

Click to read more

Posted: May 22, 2013

Keyword tags: arduinocircuitselectronicsdoorbellschematicfilter

Hacking My House #1: Building a Musical Arduino Doorbell

Earlier this year my family and I had the good fortune to move to our first home.  The home had everything we wanted, except a working doorbell.

The original doorbell button was there, complete with decades of corrosion and wires that were cut between the button and what looked to be some sort of buzzer. Initially, I planned to buy a new chime and button at Home Depot, hook up the wires, and be done with it. The chime selection, however, was sub-par.

Apparently the doorbell market is dominated by ding-dong and Westminster. Growing up, my father built a doorbell that played the first two measures of Pictures at an Exhibition. Maybe I was spoiled listening to this during my formative years, but if I wanted a doorbell that played music, I needed to build it myself.

Click to read more

Posted: Mar 27, 2013

Keyword tags: arduinocircuitselectronicsdoorbellschematiclm386

Moving Your Landline To Google Voice

For the last year and a half I have been paying Verizon anywhere between $100 - $160 a month for a phone line and static DSL line into an office that I no longer occupy.  I'm sure this sounds incredibly stupid, but the main reason I've kept paying is because the static IP hosted the main Kiddix development server and remote support server.  I finally decided that this was too much money to be paying each month just to host these servers, so they got a new home.  But, what to do with the phone number?  Even though I use my cell phone as my primary business line, it's always been nice to have a second more public line, so I decided to try and keep the number.

Click to read more

Posted: Jun 13, 2012

Keyword tags: google voiceland linenumber porting

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