Simple radio transceiver circuit walkthrough

[vk3yedotcom]

Occasionally people ask about low power transmitters etc.  FM bugs are great fun but most only go several hundred metres.  What I love about this stuff is you don't need to go too much more complex to make transmitters (in an HF amateur band) that easily go several hundred kilometres. 

Plus if you go direct conversion making it a transceiver is as easy as adding an LM386, with the other parts shared with the transmitter. I wouldn't say the thing's finished - there's a few minor refinements that would make it more pleasant to use but the results are still good.

Part 1:

Part 2:

Feel free to draw along as I sketch out the schematic!

[poptones]

How do you mount an IC on such a circuit? Glue it dead bug style?

[vk3yedotcom]

How do you mount an IC on such a circuit? Glue it dead bug style?

You could, although you don't necessarily need to glue.

If you know you don't want to use the chip again (and if you're game!) bend pins 2 & 4 90 degrees to be flush with the board with the chip mounted up side down.

However I just built the amplifier and surrounding parts on a small bit of blank matrix board (approx 3 x 3 cm). Must have been feeling rich that day as I used an IC socket!

[Prizmatic]

Great work Peter. Enjoyed the pen & paper walkthrough a lot.

[vk3yedotcom]

Great work Peter. Enjoyed the pen & paper walkthrough a lot.

Thanks Prizmatic glad you liked it.  Another circuit walkthrough has been added - this time a crystal oscillator that pulls 2 x 7 MHz crystals over a huge >50kHz range. It's been added to the transceiver and is listed as Part 3.