My weekend project: Ultra-simple W1AW Receiver

February 6, 2011 | Amateur Radio, My Projects | By: Mark VandeWettering

Okay, I’ve been wanting to actually do a little radio project for a while. So, instead of cleaning and organizing my home office some more, I decided to go ahead and tack something together. So, the project I settled on was N1TEV’s “Ultra Simple W1AW Reciever” from the May 1997 QST. I had most of the parts lying around, so I got a piece of copper clad and went to work.

Along the way I learned a few lessons:

  • When I first assembled it, the LM386 did what comes naturally: sounded like a motorboat. In discussing it with the the people on the freenode #hamradio channel (thanks especially to Aegis) I moved the power supply cap directly to pin six on the LM386 and the motorboating ceased.
  • I then hooked it an antenna, and was treated to a local FM broadcast station (106.7 FM). More discussions suggested that I could add a lowpass filter, but then I realized that I had forgotten to install the 1K emitter resistor for Q1. When I installed that, I stopped hearing the FM station.
  • I can hear the oscillator running. As I adjust the regeneration, the background noise starts low, and gets louder like I’d expect. I can also hear the signal from my FT-817 with just a short antenna hooked up.
  • As yet, I haven’t heard any live signals. Then again, I haven’t heard much on my FT-817 either, so maybe it’s just because there has been nothing to hear. W1AW broadcasts on 3.5815 Mhz, so I’ll hopefully get a chance to check it out tomorrow.

Using my RFSpace SDR-IQ receiver also shows the oscillator working:

This shows the oscillator at 3.5795, and as I adjusted the regeneration, it the frequency of the oscillator does shift. Interesting.

I’ll be testing it and playing with it some more over the next few days.


Comment from Robert AK6L
Time 2/7/2011 at 9:42 am

Very nice work, too bad W1AW wasn’t transmitting. Looking forward to reception reports and recordings!

Comment from mbbozo333
Time 2/24/2011 at 6:25 am

I want to listen space sound.Whatt your receiver to frequency.Pleace send me receiver circuits.Thanks.