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Want to modify Phils AM radio project for WWVB OCXO, dont understand propellers input Z — Parallax Forums

Want to modify Phils AM radio project for WWVB OCXO, dont understand propellers input Z

So this is old 2008, but neat


http://forums.parallax.com/discussion/105674/hook-an-antenna-to-your-propeller-and-listen-to-the-radio-new-shortwave-prog/p1


I recently stripped down a spare Ovenaire 5Mhz OCXO I would like to use the oven on an Si5351. Then use the probeller to demodulate the new BPSK signal along with receive it. This way I can beat against WWVB to set the SI5351's calibration.

As far as Phils front end I am kind of confused and would like to do it a more standard way. the 10meg ohm resistor is fine, but I do not understand the matching network for the antenna what so ever, is there a name for it? I want to use a 60Khz LC Tank as a bandpass, and then a 50 or 75 ohm matching transformer. My problem is I dont know what I am actually matching too! I read chip saying that on input a propeller pin has nearly infinite resistance and about 6pf or capacitance.... Is there a solid Z value for a propellers input?

Comments

  • Actually to add to this should I wrap my transformer on fair-right #43 it is resonant at 100khz to 1Mhz and has a wide band of 1Mhz through 50Mhz for filtering.... other than this all I have is powedered iron ripped out of switchers. Im not sure what kind of losses I would be looking at using #43 @ 60Khz?
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