[Prev][Next][Index][Thread]

RF CHOKE LOCATION

 * Original msg to: Esondrmn-at-aol-dot-com

 > From: Esondrmn-at-aol-dot-com
 > Subject: RF choke location

 ES> Richard,

 ES> Last week you said that my RF chokes should be located 4 to  
 ES> 5 feet minum from the coil primary.  Can you elaborate on    
 ES> this?  

Yep. Move the chokes back away from the primary/secondary.

 ES> Is the idea to keep them completely out of the field         
 ES> generated by the primary?  

Yes, and not only the primary, but all parts of the oscillating
Tank circuit (HV Pulse Cap, Spark Gap(s), Primary Coil, and the
cables/straps connecting these components). Inductance, other
than the secondary coil, placed too close to the tank circuit has
some detrimental effects. By placing the inductance off-axis by
90 degrees (which you did) you reduce, but do not eliminate,
these effects.

 ES> You can see by the pictures that I mailed they are only a    
 ES> couple of feet away.  What happens if they are too close?  

You get "mushy" tune mostly.

 ES> Do I get RF coupling back into the transformers? 

I could see where you might get some, but nothing a good RF
filter in the supply mains would not clear up. 

The problem is generally that you do not get a nice narrow band
output from the tank circuit with coils, chokes, or concrete
floors too close to the tank circuit. I lift the primary up off
the floor at least a foot, and move chokes, transformers, etc.
back a few feet from the tank circuit. This also reduces the
number of "incidents" that are normal while coiling.

Richard Quick
... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12