Can you design AM Radio with only "1" Active element?

Thread Starter

staryly

Joined May 8, 2016
1
Hi!
My goal is to build an AM radio for receiving in and around the 531kHz ~ 1602kHz frequency.
BUT there are some limitations.

1. Use only one Active Element (Diode, TR, IC...)
2. The free availability of passive element (R, C, L...)
3. Only one DC Power Supply.
4. AM Radio must be able to receive more than 3 channels.

so, I have designed basic AM Radio with envelope detector.
but I want to improve performance of radio in terms of QoS(Quality of Service).
How can I upgrade my radio?
 

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recklessrog

Joined May 23, 2013
985
Well, this is interesting, a little while ago, we were having discussions as to whether a diode is "active" and it depends on the application and your interpretation of "active" If you consider a diode as passive, then a crystal radio uses no active parts and vice versa.
There used to be a little metal cased 3 pin (I think) a.m radio chip that only needed a tuned circuit, a couple of resistors, battery and earpiece. Someone on here will remember it better than me.
Try googleing T.R.F a.m receiver.
Just remembered the chip was an Zn414
 
Last edited:

RichardO

Joined May 4, 2013
2,268
Maybe what you want is a reflex receiver.

Note the single active device!

Oh, drat it has a carborundum point contact diode. :D
 

KL7AJ

Joined Nov 4, 2008
2,224
Hi!
My goal is to build an AM radio for receiving in and around the 531kHz ~ 1602kHz frequency.
BUT there are some limitations.

1. Use only one Active Element (Diode, TR, IC...)
2. The free availability of passive element (R, C, L...)
3. Only one DC Power Supply.
4. AM Radio must be able to receive more than 3 channels.

so, I have designed basic AM Radio with envelope detector.
but I want to improve performance of radio in terms of QoS(Quality of Service).
How can I upgrade my radio?
Here ya go.
 

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Glenn Holland

Joined Dec 26, 2014
681
I've read about a phenomenon where some people can pick up AM radio through fillings in their teeth.

It's not a case of schizophrenia and there have been scientific tests that prove it actually happens. There are also cases where a metal fence was able to pick up AM signals that could be heard by persons nearby.
 

SamR

Joined Mar 19, 2019
1,469
At work, we were near an AM broadcast tower so it was readily available on the telephones any time you made a call.
 

MrAl

Joined Jun 17, 2014
6,770
I've read about a phenomenon where some people can pick up AM radio through fillings in their teeth.

It's not a case of schizophrenia and there have been scientific tests that prove it actually happens. There are also cases where a metal fence was able to pick up AM signals that could be heard by persons nearby.
So many things can make up a diode.
 
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