[Aavso-sid-list] Gyrator II receiver

[ChrisAtUpw at aol.com]

In a message dated 27/03/2008, mthompson14 at yahoo.com writes:  
 
I  just recently got my Gyrator II receiver up and running. I've been running 
 some tests, and all seems to be working as to be expected with the receiver  
and amplifier portion. However when I hook a meter up to the  
rectifier-integrator with the gain turned all the way up I am only seeing a  difference of 
about 10 millivolts (19mV - 32mV) between sun up and sun  down.

Is this to be expected or should I be reading higher values?  Could it be 
that my loop antenna just isn't pulling in enough  signal?



Hi Mike,
 
    The Gyrator II is designed for use with a long  wire aerial and it has a 
small aerial coupling capacitor ! !
 
     You need to tune it to a radio station which  is well over 500 miles 
away, or you will only pick up a fairly constant ground  wave. The level should 
change quite a lot as you tune through a  station.
 
    If you try to use it with an inductive loop, you  need the same small or 
a smaller coupling capacitor, but you also need to tune  both the loop and the 
gyrator at the same time. This is not impossible to do,  but certainly more 
difficult. An untuned coil of wire does not pick up a RF  signal very strongly. 
The Q of a tuned coil may be over 30, so it gives that  much more output at 
it's resonant frequency.
 
    Try it with 100 ft of aerial wire?
 
    Regards,
 
    Chris Chapman




   
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