Technical Topics > The RF Workbench
which type of crystal
ff:
--- Quote from: Antennae on March 09, 2014, 2233 UTC ---should the 7 turns section go toward the top of the diagram or the bottom?
--- End quote ---
Definitely towards the bottom. Another thing - the entire 21 turns resonates on freq and your 4 turn secondary should be wound over nearly the entire length for best results. You might already be building your Mighty Mike from Make RF's website but if not, check it out:
http://makerf.com/posts/mighty_simple_shortwave_transmitter
He has an excellent site for newbie transmitter builders - lots of good stuff! Once you get your unit working his Altoids can Low Pass Filter is a highly recommended add-on.
ff:
One more thing Antennae - your xtal might still be good BUT your transistor is possibly blown. Energizing it without the antenna ground connected might have zorched the transistor, however mebbe not. It's hard to tell considering the low power level of the Mighty Mike. I mention it only to alert you to the possibility. Ain't transmitter building FUNNNNN? Now you know why its a "Black Art"...
Antennae:
Its a fun experiment for the 40meter ham band. I can't wait to make some contacts with it.
-Yup, its from makerf.com. He's a great resource!
-Whew, thats how my coil ended up with the 7 on the bottom. And thanks for specifying to spread the secondary over the whole thing. That was another question. I did that because I was able to see it like that on makerf's pictures.
-It even worked on the breadboard with a coil made from enamel wire from an old RC motor. It was all lumpy so I got some new wire for my purdy version.
-Zorched transistor eh? I hope not, I tried it with another one I had and it still wouldn't work. If I had an extra variable capacitor I could do a test on the crystal and make certain what the problem is.
I can't help it, take a look at my baby!
Antennae:
Oh yeah, I had the antenna and antenna's ground connected with a 50ohm load...mostly. BUT I had the antenna ground connected to the ground of the Mighty Mite circuit when it shouldn't be.
Antennae:
It was the crystal that was busted. I installed a big honkin' FT 243 crystal and it works again, yay.
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