Well, it turns out that yesterday was a GREAT day for a new receiver. When I got home from work 30 meters was open. I fired up the new receiver and the FLDIGI program. Immediately I started to see and decode PSK-31 signals. I quickly switched over to the WSPR program and right away I could see the little two minute WSPR sigs. Here is what my screen looked like:
The program also began to automatically upload reports to WSPR HQ. Here is the report I found on the WSPR web site this morning:
I know all this WSPR and digi stuff often seems to be very computer-centric, and very "appliance radio," but I think this little project shows how we can have the best of both worlds: This rig combines a laptop computer and some pretty sophisticated software with a VERY simple, discrete component, homebrew direct-conversion receiver.
OK. So you see that I left a lot of space on the PC board. That's where the DSB transmitter (for WSPR and possibly PSK-31) will go.
BTW: You can keep an eye on my reception reports by going to the Database section of the
WSPRnet site and plugging my call (I0/N2CQR) into the "reporting station" block. I'll leave the receiver on today.
The Maker blog has a really great 20 minute podcast interview with Forrest Mims. He talks about his recently deceased friend Ed Roberts, founder of MITS and creator of the Altair 8800. The interview is really great. You guys will like it. Look for the little audio bar just underneath the article on this page:
Well, it turns out that yesterday was a GREAT day for a new receiver. When I got home from work 30 meters was open. I fired up the new receiver and the FLDIGI program. Immediately I started to see and decode PSK-31 signals. I quickly switched over to the WSPR program and right away I could see the little two minute WSPR sigs. Here is what my screen looked like:
The program also began to automatically upload reports to WSPR HQ. Here is the report I found on the WSPR web site this morning:
I know all this WSPR and digi stuff often seems to be very computer-centric, and very "appliance radio," but I think this little project shows how we can have the best of both worlds: This rig combines a laptop computer and some pretty sophisticated software with a VERY simple, discrete component, homebrew direct-conversion receiver.
Here is the latest picture of my version of the W3PM WSPR receiver. You can see the Ugly Weekender AF amp in the upper left. No front end of any kind yet -- the sig goes right from the antenna jack into the RF pin on the SBL-3 diode ring mixer.
Just look at that circuit! That's a complete QRSS beacon transmitter, including a multivibrator (the two transistors on the left) to generate a recognizable pattern on the grabber screens. This diagram appears in SPRAT 134. Hans Summers ran this rig with just a couple of volts from his homebrew bleach-based battery system back in 2008. I plan on putting a version of this rig into the solar powered lawn lamp I showed you two posts ago (scroll down). 
I'm really into Colpitts oscillators lately. I blame Gene, W3PM. He reminded me of the fact that these little one transistor stages can pump out the 7 dbm needed to drive a diode ring mixer. Gene sent me a note warning that I'd have to take special precautions to ensure stability, but I found that this circuit never strayed more than 20 hertz in the course of a full day of oscillating. 
