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From: semi
Date: 5/12/02
Time: 12:37:19 PM
Remote Name: 203.106.108.38
Does any one where i can get this super heterodyne receiver for gsm1800 receiver circuit??? Please...
From: Harvey Harbicht
Date: 3/30/99
Time: 10:48:02 AM
Remote Name: 169.207.90.54
To put it simply, a xtal radio works off of power that is already present. That's why the Military loved xtal sets during the war(s). You could listen and the enemy couldn't trace any spurious emissions coming from the radio*. Being 100% passive and having NO active powered circuits whatsoever** a xtal set can't generate ANYHTHING.
To transmit you need to create new power. A LOT of power compared to the signal being generated. -------------------- *That's how they find guys that are stealing cable. You can park outside a house and pick up the leakage from his TV. IE: Watch what he's watching.
** Except maybe a battery to bias a poor detector. It still doesn't generate any signal though.