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Sunday, March 28, 2010

Building W3PM's Colpitts Oscillator


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

1 comment:

  1. Hi Bill,

    I 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/

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