One of the best things about having your amateur radio license is that it allows you to legally build and operate transmitters. If you want to build a full-featured single-sideband rig with digital modes, have at it. But there’s a lot of fun to be had and a lot to learn from minimalist builds like this Michigan Mighty-Mite one-transistor 80-meter band transmitter.
If the MMM moniker sounds familiar, it may be because of this recent post. And in fact, [W2AEW]’s build was inspired by the same SolderSmoke blog posts that started [Paul Hodges] on the road to his breadboard and beer can build. [W2AEW]’s build is a bit sleeker, to be sure, but where the video really shines is in the exploration and improvement of the signal quality. The basic Mighty-Mite outputs a pretty dirty signal – [W2AEW]’s scope revealed 5 major harmonic spikes, and what was supposed to be a nice sine wave was full of divots and potholes. There’s only so much one transistor, a colorburst crystal and a couple of capacitors can do, so the video treats us to an explanation of the design of the low-pass filter needed to get rid of the harmonics and clean up the output into a nice solid sine wave.
If your Morse skills aren’t where they should be to take advantage of the Might-Mite’s CW-only mode, then you’ll need to look at other modulations. Maybe a tiny FM transmitter would suit your needs better?
Thanks for the post of my video!
Thanks for your videos Alan, excellent as always.
I’d like to second what [Darren] said.
You’re welcome! And keep the vids coming – I always learn something.
I’m actually trying to find more info on AA1TJ’s 150uW QRP beacon that was recently heard at 125km. If you’ve got any connections to Mike, let me know – I need schematics, pix, anything.
73
For those interested in minimalist transmitters consider this old example:
http://www.rfcafe.com/references/popular-electronics/tunnel-diode-september-1960-popular-electronics.htm
Nice! I did a video on the Tunnel Diode too:
http://www.youtube.com/watch?v=PuG8CCUbg58
Clear, concise and informative. Really a great tah-dah moment. Thanks, 73 Tom NY2RF
Congratulations on the new position at the League, Tom!
If you like simple transcievers, you should also check out the Pixie and the SMT vesion, the KnightSMiTe.
http://www.qsl.net/kl7aqc/frAL7FS2.html is a good intro. The Knight SMiTe page: http://www.knightlites.org/projects/knightsmite/index.htm
There are a nearly infinite amount of Pixie pages out there, I found close to a hundred and never hit bottom… Somebody should do a Pixie link list!
Im not much into radio but this was a good into video and was really well done. Thanks.
I am totally into this. I really want to build this but my brain cant figure it out. is there a tutorial out there?
Here is another QRP rig that might interest some people. http://bit.ly/KeychainQRP