Hey all,

I'm building a MW transmitter from this book, for a school project.

I'm confused about the directions regarding L2 (high frequency coil). For building my own coil, it calls for winding the AWG "ON" a resistor. What do they mean by "on" a resistor? Because it doesn't show a resistor, at the coil, in the schematic. The coil in the schematic just has a dotted line which would mean ferrite core correct?

What's the purpose of this resistor they call for?

The section about L2 is at the bottom of picture 2. I attached all the photos as well.

Thanks for the help

 

Take it completely literally. You wind the coil using the resistor as the coil former. Connect the ends of the winding to the resistor leads next to the body.
it isn't shown on the circuit diagram because 100k will have virtually no effect in parallel with the coil. (At 1MHz the coil will have a reactance of no more than 3k)

 

The resistor is used as a "coil form" to allow you to make the turns with a uniform diameter and spacing. You may or may not need to remove the "coil form" after you finish winding it. You can actually use any solid material for a "coil form". It does not have to be a resistor. PVC pipe can be a handy alternative.

 

The circuit does not look like the "Hartley" oscillators I am familiar with. And the comment about nothing being critical is not at all what I am familiar with in radio frequency circuits.
Have you built the circuit, or are you stopped because of the randomness of the instructions??
For the coil I suggest a diameter of about 1/4 to 3/8 inch, (at least half a CM but not more than one CM.)

What publication is that circuit in??

 

I believe it is this book: available on amazon for a princely sum.

Pirate Radio and Video: Experimental Transmitter Projects (Electronic Circuit Investigator), Braga, Newton C., eBook - Amazon.com

It does not have very high ratings. Less than 50% are 5-star. Gee, I wonder why.