[AMRadio] AMPX article on mod reactor

Donald Chester k4kyv at hotmail.com
Mon Aug 15 23:00:55 EDT 2005

>>This would be the article concerning the value and design of the reactor 
>>and blocking cap value.
>>I will be building up a modulator using either a CVM4 or 5
>Depends on how low in frequency you want to pass through the modulation 
>transformer, Mark,
>and how much current you'll be running in the final section of the rig.
>Typically, 8HY per 1000 ohms of impedance load in the final is a pretty 
>good rule of thumb.

That's about the standard value used in AM broadcast transmitters.

>8~10uF of coupling should do nicely.  Depending on where you put the 
>coupling, will determine
>how much of a voltage rating the capacitor needs to be.

Actually, broadcast transmitters use much less than than, and still boast of 
flat response down to 30~ or lower.  RCA transmitters typically use 1 mfd.  
Gates uses 2 mfd.  I use 4 mfd in my homebrew rig @ 4000 ohms modulating 

73, Don k4kyv

More information about the AMRadio mailing list

This page last updated 22 Jan 2018.