inductive coupling


lrdheat
 

I notice that both my digital SANGEAN PR-D5 and my analog SONY ICF-S5W and EX5 all can be tuned to a given frequency, and then used to boost a signal significantly on an ultralight tuned to the same frequency. My question is, why do the analogs work as a booster even when off while the digital works as a booster only when turned on?


satya@...
 

Hi Richard:

On analog sets, the tuning capacitor is never disconected from the antenna
coil, so the L-C circuit that makes the antenna resonate is always
completed. With a PLL set, a variable capacitance diode (varicap) is used
to dial up the right frequency, but the diode is only "on" when the radio
itself is on, so powering the radio down means you've got a ferrite loop
with no capacitor to tune it.

Hope this helps - Kevin S
Bainbridge Island, WA

I notice that both my digital SANGEAN PR-D5 and my analog SONY ICF-S5W and
EX5 all can be tuned to a given frequency, and then used to boost a signal
significantly on an ultralight tuned to the same frequency. My question
is, why do the analogs work as a booster even when off while the digital
works as a booster only when turned on?