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Author Topic: Portable AM Crystal Radio  (Read 4746 times)
VU2NAN
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« on: January 21, 2017, 05:10:55 AM »

May be viewed at

https://nandustips.blogspot.in/2017/01/portable-am-crystal-radio.html

73,

Nandu.
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ONAIR
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« Reply #1 on: January 21, 2017, 01:25:06 PM »

   Nice!  I used to use something similar to that to monitor my AM transmitted audio.
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VU2NAN
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« Reply #2 on: January 21, 2017, 05:51:29 PM »

Thanks, OM!

73,

Nandu.
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AC6AN
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« Reply #3 on: January 22, 2017, 09:52:23 AM »

Nandu, the circuit makes no sense.
Try a counterpoise and couple in the middle with a transformer.
The secondary will have a tuning capacitor in parallel and one Ge diode and headphones in series.
Since the antenna is so short, you might want to look into using a zero-threshold mosfet instead of the Ge diode.
A good reference is this article: http://www.arrl.org/files/file/Technology/tis/info/pdf/culter.pdf.
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VU2NAN
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« Reply #4 on: January 22, 2017, 06:38:26 PM »

Hi OM Ori,

I suppose stray capacitance, between headphone leads, body and ground and that between telescopic and nearby overhead cables, does the trick!

73,

Nandu.
« Last Edit: January 22, 2017, 06:55:57 PM by VU2NAN » Logged

VK4FFAB
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« Reply #5 on: January 22, 2017, 07:54:31 PM »

Thanks for sharing Nandu, I always enjoy seeing your projects.

Rob.
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VU2NAN
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« Reply #6 on: January 22, 2017, 09:02:15 PM »

Thanks, OM Rob.

Your blog / projects carry the marks of a true professional!

73,

Nandu.
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VU2NAN
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« Reply #7 on: January 22, 2017, 09:31:57 PM »

Thanks, OM Rob.

Your blog / projects bear the mark of a true professional!

73,

Nandu.
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VU2NAN
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« Reply #8 on: January 25, 2017, 09:00:07 PM »

There's been an update.

https://nandustips.blogspot.in/2017/01/portable-am-crystal-radio.html

73,

Nandu.
« Last Edit: January 25, 2017, 09:10:03 PM by VU2NAN » Logged

VU2NAN
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« Reply #9 on: March 07, 2019, 09:01:25 AM »

Here's another update.



https://nandustips.blogspot.in/2017/01/portable-am-crystal-radio.html

73,

Nandu.



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