I took a break from all the computer stuff and decided to melt some solder this weekend.
W3PM has a neat WSPR rig on his site. I decided to build at least parts of it. Today I put together the Colpitts oscillator. I really like this circuit -- it produces enough power to drive a diode ring mixer directly. Mine went together very smoothly. Sure enough, mine produces about 10 mW.
It was good to get back to solder melting. I used circular pads sent to me by Jerry NR5A. And parts sent by Jim AL7RV, and by Mike AA1TJ. EMRFD provided very useful background info on the circuit. I powered the prototype up with my Kempton Park power supply with the current limiting chip provided by Tony G4WIF. So it was a like a team effort. Thanks to all!
I'll try to get the next podcast out mid-week.
73
Posts
Hi Bill,
ReplyDeleteI used that particular Colpitts circuit for simplicity and adequate output power to drive the SBL-1 mixer. The trade-off is stability. The oscillator should be housed in a small metal box surrounded by insulating material. There are many oscillator/buffer-amplifier circuits on the web that provide better stability that the experimenter may want to use to drive the SBL-1.
73,
Gene W3PM GM4YRE
http://www.knology.net/~gmarcus/